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					                  Warm up
• DNA is found in all living things. The
  shape of DNA is like a twisted ladder and
  is called a double helix. One molecule of
  DNA can contain millions of atoms. When
  unraveled, there are about 6 feet of DNA
  in each of your bodies cells.
• What does DNA stand for?
• What kind of information is stored on
  DNA?

August 11, 2011                               1
                  What is Heredity?
• Traits – traits are the characteristics of an
  organism.
• During fertilization, male and female sex
  cells join together.
• Each of these sex cells contains material
  that affects the development of the
  offspring.
• Traits that are passed from parent to
  offspring are called inherited traits.
• Eye color is an example of inherited traits.
August 11, 2011                                   2
                  Heredity
• The passing of traits from parents to
  offspring is called heredity.
• The field of biology that studies heredity is
  called genetics.




August 11, 2011                                   3
                  Gregor Mendel
• Gregor Mendel was an
  Australian monk. He was one
  of the first people to study
  heredity.
• Mendel showed how the traits
  in pea plants are passed from
  one generation to the next
• He is called the Father of
  Genetics
August 11, 2011                   4
• Mendel used seven different
  pairs of traits:
• 1) Seed form - round or
  wrinkled.
• 2) Color of seeds - yellow or
  green (contents).
• 3) Color of seed coat white or
  grey.
• 4) Color of unripe seedpods -
  green or yellow.
• 5) Shape of ripe seedpods -
  inflated or constricted between
  seeds.
• 6) Length of stem - short 9 - 18
  inches of long 6 - 7 feet.
• 7) Position of flowers - axial (on
  stem) or terminal (at tip of
  stem).
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                  Heredity of Twins
• Twins are siblings born at the same time.
• Two types of twins - fraternal and identical.




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                  Identical Twins
                  • Identical twins develop
                    from one egg,
                    fertilized by a single
                    sperm.
                  • Identical twins are
                    genetically identical.
                  • They inherit the exact
                    same traits.
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             Fraternal Twins
• Fraternal twins develop from
  two separate eggs that have
  been fertilized by two
  separate sperm cells.
• Fraternal twins are
  genetically different from
  each other. They can be
  different sexes.




August 11, 2011                  8
• Twin animation Video
• http://pennhealth.com/health_info/animatio
  nplayer/twins.html




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                  Genetic Traits Lab
• Choose a partner
• Complete the data table for you and your
  partner. Be neat. Use a ruler & complete
  headings!
• Collect the class data and complete the
  rate of frequency data table for the class
• Everyone must have a completed data
  tables
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Name ___________________-

Trait                               Yes        NO

Tongue Rolling
Widow‘s Peak
Dimples
Pierced Ears
Earlobe Attachment                  attached   free
Mid-Digital Finger Hair
Naturally Curly Hair
Cleft Chin
Hitchhiker's thumb
Can see the color‘s red and green
Allergies
Right-handed
Freckles 2011
August 11,                                            11
                  Assignment
• Complete worksheet 3-1
• Complete study worksheet 11-1




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                           Warm up
• Normal human body cells each contain 46 chromosomes. The cell
  division process that body cells undergo is called mitosis and
  produces daughter cells that are virtually identical to the parent cell.
  Answer the questions that follow.
• 1. How many chromosomes would a sperm or an egg contain if
  either one resulted from the process of mitosis?


• 2. If a sperm containing 46 chromosomes fused with an egg
  containing 46 chromosomes, how many chromosomes would the
  resulting fertilized egg contain? Do you think this would create any
  problems in the developing embryo?


• 3. In order to produce a fertilized egg with the appropriate number
  of chromosomes (46), how many chromosomes should each sperm
  and egg have?


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                  Gametes
                  • Every body cell of an
                    animal contains the same
                    number of chromosomes
                  • Sperm cells and egg cells
                    are reproductive cells
                  • Reproductive cells are
                    also called gametes


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• Gametes develop form
  special cells in the
  body.
• During the formation of
  gametes, the number of
  chromosomes is cut in
  half.
• Each gamete contains
  only 1/2 as many
  chromosomes as a
  body cell
• The process by which
  gametes form is called
  Meiosis
August 11, 2011             15
Number of Chromosomes in Various Organisms

Organism            Body Cells   Gametes

Fruit Fly           8            4

Bull Frog           26           13

Human               46           23



  August 11, 2011                            16
                  Meiosis

• The process of
  meiosis occurs in 2
  parts, meiosis I and
  Meiosis II.
• Meiosis includes 2
  cell divisions
  instead of 1


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                  Prophase part 1
• Chromosomes
  replicate and
  nuclear
  membrane
  disappears
• Crossing over
  causes genetic
  variations

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• In prophase I, doubled
  chromosomes condense
  again. . . BUT, UNLIKE
  mitotic prophase, the
  members of each
  chromosome pair attach
  to each other. These
  paired chromosomes
  actually exchange
  pieces of themselves
  with each other -- called
  crossing over.

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                  Metaphase part 1
• Chromosomes
  line up in pairs




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                  Anaphase Part 1
• Chromosome
  pairs separate




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                  Telophase Part 1
• Cells Pinch
  Apart




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                  Prophase part 2
• Chromosomes do not need to replicate




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                  Metaphase part 2
• Chromosome copies line up single file




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                  Anaphase Part 2
• Chromosome copies split and separate




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                  Telophase part 2
• Cells pinch apart and nuclear membrane
  forms




August 11, 2011                            26
                  • Four daughter
                    cells are formed
                    with half the
                    number of
                    chromosomes
                  • These new cells
                    are called
                    gametes

August 11, 2011                        27
• Meiosis 1 is similar to mitosis except
  that the chromosome copies do not
  split
• Instead, the chromosome pairs
  separate.
• So we get 2 daughter cells that are
  different from each other




August 11, 2011                            28
• After Meiosis II, the daughter cells formed
  only have ½ the chromosomes compared
  to the number of chromosomes in normal
  body cells
• Human gametes only contain 23
  chromosomes



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                  Nondisjunction
• During Meiosis, chromosome pairs
  separate to form gametes (sex cells)
• Sometimes the gametes do not separate
  correctly.
• This is called nondisjunction




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• In nondisjunction, both chromosome pairs
  go to the same gamete
• As a result one gamete has too many
  chromosomes and the other gamete has
  too few.
• If either of these gametes unites with a
  normal gamete during fertilization, the
  organism does not develop properly.



August 11, 2011                          33
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• Down Syndrome is
  caused by
  nondisjunction
• The body cells of a
  person with Down
  Syndrome contain 47
  chromosomes instead
  of 46.

August 11, 2011         35
                  Assignment
• Complete worksheet 3-2
• Compete Study guide for section 11-4
• Complete DNA challenge. I want at least
  60 words!




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                  Warm Up
• Read the article ―DNA Structure‖
• Complete the blanks and answer the
  questions.
• Be prepared to share.




August 11, 2011                        37
What is DNA?
• Chromosomes
  are made of large
  molecules called
  DNA
• DNA stands for
  deoxyribonucleic
  acid


August 11, 2011       38
                  • DNA structure was
                    discovered in 1953 by
                    an American scientist,
                    James Watson , and a
                    British Scientist,
                    Frances Crick.
                  • They created the first
                    model of a DNA
                    molecule
August 11, 2011                              39
           Structure of DNA
• DNA looks like a twisted
   ladder.
• We call this structure a double
   helix.
• The sides of the ladder are
   made up of sugars and
   phosphates.
• The steps of the ladder are
   made of nitrogen bases.
• Each base pairs with another
   specific base to form the steps
   of the
August 11, 2011 ladder               40
       Base Names
• There are 4
  nucleotide bases
  that make up a
  DNA molecule.
• They are adenine,
  thymine, cytosine
  and guanine.


August 11, 2011       41
                  Base Pairing
                           • In a double
                             helix, Adenine
                             always pairs
                             with thymine
                             and cytosine
                             always pairs
                             with guanine.



August 11, 2011                               42
                  Replication
• During mitosis, cellular DNA copies itself.
  This is called replication.
• The DNA ladder unzips itself and new
  nitrogen bases pair up with the ladder.
• After replication, we have new DNA
  strands that are exact copies of the
  original DNA molecule.


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                  The Role of DNA
• A single DNA molecule, or ladder, can
  have thousands of steps, or base pairs.
• The number and arrangement of these
  steps forms a genetic code.




August 11, 2011                             45
• DNA does three critical things:
1. Genes carry information from one
   generation to another.
2. Genes determine the heritable (traits that
   are passed to offspring) characteristics of
   an organism.
3. Copy DNA every time cell division
   occurs.



August 11, 2011                             46
                  Assignment
• Complete worksheet 3-3
• Complete text study sheets 12-1 and 12-2




August 11, 2011                          47
                      Warm Up
• DNA contains the information that a cell needs to carry
   out all of its functions. In a way, DNA is like the cell‘s
   encyclopedia. Suppose that you go to the library to do
   research for a science project. You find the information
   in an encyclopedia. You go to the desk to sign out the
   book, but the librarian informs you that this book is for
   reference only and may not be taken out.
1. Why do you think the library holds some books for
   reference only?
2. If you can‘t borrow a book, how can you take home the
   information in it?
3. All of the parts of a cell are controlled by the information
   in DNA, yet DNA does not leave the nucleus. How do
   you think the information in DNA might get from the
   nucleus
August 11, 2011 to the rest of the cell?                       48
                     RNA


• DNA controls an organism‘s traits by
  producing certain proteins at certain times.
• This is called protein synthesis.
• Proteins are made of molecules called
  amino acids
• These amino acids are made by the
  ribosomes of cells


August 11, 2011                              49
• The DNA code is located inside the
  nucleus of a cell.
• A special molecule carries the code from
  the nucleus to the ribosome.
• This molecule is RNA, or ribonucleic acid.




August 11, 2011                                50
                  RNA Structure
• RNA has only
  one side of the
  ladder shape.
• RNA contains the
  nitrogen base
  uracil instead of
  thymine.



August 11, 2011                   51
                  How it works?
• RNA copies the code from the DNA strand
  and then carries it to the ribosome.
• RNA acts as a pattern on which proteins
  can be built.
• Ribosomes read the RNA strand and
  attach the correct amino acids.
• The amino acids link together and form a
  protein

August 11, 2011                          52
                  Types of RNA
1. Messenger RNA – Contain instructions
   for assembling amino acids and proteins.
2. Ribosomal RNA – Found inside
   ribosomes. Helps the ribosome make
   new proteins
3. Transfer RNA – transfers each amino
   acid to the ribosomes as it is specified by
   the codes on mRNA.
August 11, 2011                              53
        Transcription & Translation
                  • During transcription, the
                    DNA molecule is unzipped
                    and separated. An enzyme
                    uses one strand of DNA as
                    a template to make a strand
                    of mRNA.
                  • During translation, the cell
                    uses information from the
                    mRNA to produce proteins.


August 11, 2011                                54
                  Transcription
• http://www-
  class.unl.edu/biochem/gp2/m_biology/ani
  mation/gene/gene_a2.html
• http://www.stolaf.edu/people/giannini/flash
  animat/molgenetics/transcription.swf




August 11, 2011                             55
                  Translation
• http://www-
  class.unl.edu/biochem/gp2/m_biology
  /animation/gene/gene_a3.html
• Complete internet lab




August 11, 2011                     56
                  Assignment
• Complete study Guide 12-3
• Complete worksheet messenger rna




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                  Warm Up
• Describe three differences between RNA
  and DNA
• Be specific and use complete sentences




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          Chromosomes
• Fine, threadlike
  structures located in the
  nucleus of the cell are
  called chromosomes.
• Chromosomes control
  heredity



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 This is a real picture of a person's chromosomes –
 taken from a single cell, stained and spread on a microscope
 slide.
August 11, 2011                                                 60
                  Karyotypes
                        • A karyotype is a
                          display of an
                          organism‘s
                          chromosomes,
                          organized by size
                          and shape.
                        • Sometimes the
                          chromosomes in
                          a karyotype are
                          numbered.
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             Chromosome Structure
• Chromosomes are
  made of chromatin.
• Chromatin is a very
  long, thin strand of DNA
• The strands are
  wrapped around special
  proteins that help to
  keep the chromatin in
  an x-shape.

August 11, 2011                     63
• Each side of the x shaped chromosome is
  called a chromatid.
• Chromatids are exact copies of each
  other.
• They are held together by a centromere.
• Chromatin does not usually look like this. It
  only forms tight coils when it is about to
  divide.



August 11, 2011                              64
   Chromatin




                  Chromatid
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                  Chromosome Pairs
• In organisms that sexually reproduce,
  chromosomes exist in pairs.
• This is because each parent contributes to
  the same chromosome.
• Karyotypes show chromosomes arranged
  in pairs.




August 11, 2011                            66
• To "read" a set of human chromosomes,
   scientists first use three key features to identify
   their similarities and differences:
1. Size.
2. Banding pattern. The size and location of bands on
   chromosomes make each chromosome pair unique.
3. Centromere position. Centromeres are regions in
   chromosomes that appear squeezed together.
• Using these key features, scientists match up the
  23 pairs -- one set from the mother and one set
  from the father.




August 11, 2011                                          67
                  Alleles
• Alleles are different versions of the same
  gene.
• Alleles for a specific gene are always
  found in the same location on the same
  chromosome.
• Example – plants may have an allele for
  purple flowers or an allele for white
  flowers.


August 11, 2011                                68
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                  Assignment
• Complete Karyotype Lab
• Complete worksheet 3-4
• Read study sheet 14-2




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                  Bell Ringer
• Read the Chris Burke story
• Fill in the blanks
• Answer the questions.




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                   Warm Up
•      Answer the following questions using
       complete sentences.
1.     Where are chromosomes located?
2.     When does Chromatin form a
       Chromatid?
3.     Where are genes located?
4.     What are alleles?

August 11, 2011                               72
                  Mutations
• A Mutation occurs when a DNA gene is
  damaged or changed in such a way as to
  alter the genetic message carried by that
  gene.
• A Mutagen is an agent of substance that
  can bring about a permanent alteration to
  the physical composition of a DNA gene
  such that the genetic message is changed.

August 11, 2011                           73
           Chromosomal mutations
• Mutations may involve whole chunks of
  chromosome or just changes in single
  bases.
• A length of chromosome may be
  translocated to another place on the
  chromosome, or be inverted.
• Whole chromosomes may fuse.


August 11, 2011                           74
                   Mutagens
1.     Chemical Mutagens
2.     Radiation
3.     Sunlight (ultraviolet radiation)
4.     Spontaneous mutations




August 11, 2011                           75
     Genetic Disorders caused by
     Chromosomal Abnormalities




August 11, 2011                    76
                  Stumpy the duck
                      • Stumpy, an 8-day-old
                        duckling born in
                        Britain, has a rare
                        mutation: 4 legs
                      • A rare mutation has left
                        the eight-day-old
                        duckling with two nearly
                        full-sized legs behind the
                        two he runs on.

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                  And then there were two..Stumpy without his third
                  limb

August 11, 2011                                                       79
                  Lionhead Rabbit
•




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                  American Curl
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                  Cornish REx




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                  Sphinx




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                  Webbed Feet




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            Down Syndrome
• Down Syndrome is a genetic
   disorder caused by extra
   genetic material. It affects
   over 350,000 people in the
   United States alone and is the
   most common (1 in 800 live
   births) imbalance in the
   number of autosomes in
   people. The effects of Down
   Syndrome vary greatly from
   person to person but can
   include mental retardation,
   eyes that slant upward, and
   heart defects.
• People with Down Syndrome
   have 3 copies of chromosome
   21. For this reason, Down
   Syndrome is also called
   "Trisomy 21".
August 11, 2011                     90
                     Turner Syndrome
                  • Turner Syndrome affects 60,000
                    girls and women in the United
                    States.
                  • Symptoms include short stature
                    and lack of ovarian development.
                    Other features, such as webbed
                    neck, arms that turn out slightly at
                    the elbow, and a low hairline in
                    the back of the head are
                    sometimes seen.
                  • Women and girls with Turner
                    Syndrome have only one X
                    chromosome.
                  • the single X chromosome comes
                    from the mother's egg because the
                    father's sperm that fertilizes the
                    egg is missing a sex chromosome.
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              Klinefelter Syndrome
• Klinefelter Syndrome
  occurs in 1 in 500 to 1 in
  1000 live births.
• People with this disorder
  are often tall and usually
  do not develop secondary
  sex characteristics such as
  facial hair, or underarm
  and pubic hair.
• Men and boys with
  Klinefelter Syndrome have
  a Y chromosome and 2 X
  chromosomes.




August 11, 2011                      94
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              Cri du chat Syndrome
                        • Cri du chat is a rare syndrome
                          (1 in 50,000 live births)
                          caused by a deletion on the
                          short arm of chromosome 5.
                          The name of this syndrome is
                          French for "cry of the cat,"
                          referring to the distinctive cry
                          of children with this disorder.




August 11, 2011                                         96
                  Williams Syndrome




• Williams Syndrome is caused by a very small chromosomal
  deletion on the long arm of chromosome 7.
• Because they lack the elastin protein, people with Williams
  Syndrome have disorders of the circulatory system, also
  known as vascular disorders.
• The chromosomal deletion that causes Williams Syndrome
  is so small that it cannot be seen in a karyotype. However,
  the deletion can be observed using a special technique
  called fluorescent in situ hybridization, or FISH.
August 11, 2011                                             97
                  Patau Syndrome
• Trisomy 13 – extra chromosome #13




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Edward Syndrome – Trisomy 18
• It is caused by the presence of three —
  instead of two — chromosomes 18 in a
  fetus or baby's cells.




August 11, 2011                             100
                  XYY syndrome
• XYY syndrome is an trisomy of the sex
  chromosomes in which a human male receives
  an extra Y chromosome, producing a 47,XYY
  karyotype.
• Most often, this chromosomal change causes no
  unusual physical features or medical problems.
• 47,XYY boys have an increased risk of learning
  difficulties (in up to 50%) and delayed speech
  and language

August 11, 2011                               101
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                  • There are currently no treatments
      Progeria      for progeria, which is a genetic
                    disorder estimated to affect one
                    child in 4 million.
                  • When they are born, children with
                    progeria appear normal
                  • But, as they grow older, they
                    experience growth retardation and
                    show dramatically accelerated
                    symptoms of aging -- namely hair
                    loss, skin wrinkling and fat loss.
                  • Accelerated cardiovascular
                    disease also ensues, typically
                    causing death from heart attack or
                    stroke at about the age of 12.


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                  Anencephaly




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    Hydrocephalic - enencephalic




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                  Assignment

• Complete study guide 12-4




August 11, 2011                117
                  Bell ringer
• What are the four types of mutagens?




August 11, 2011                          118
                                   Warm up
     Parents                       First Generation   Second Generation
     Long stems  short stems      All long           787 long: 277 short
     Red flowers  white flowers   All red            705 red: 224 white
     Green pods  yellow pods      All green          428 green: 152 yellow
     Round seeds  wrinkled seeds All round           5474 round: 1850 wrinkled
     Yellow seeds  green seeds    All yellow         6022 yellow: 2001 green

• 1. In the first generation of each experiment, how do the
  characteristics of the offspring compare to the parents‘
  characteristics?
• 2. How do the characteristics of the second generation
  compare to the characteristics of the first generation?

  August 11, 2011                                                                 119
                  Genes and Traits
• Genes are inherited factors that produce
  certain traits.
• Each trait of an organism is determined by
  at least one gene from each parent.




August 11, 2011                           120
 Homozygous and heterozygous
• An organism is homozygous if it has 2 like
  genes for a given trait. (TT, tt)
• Organisms that have two unlike genes for
  a trait are heterozygous for that trait (Tt)




August 11, 2011                              121
                  Dominant Genes
• When a dominant gene is present the
  recessive genes are all hidden.
• But if there are no dominant genes
  around we can see recessive genes




August 11, 2011                         122
                  Gene Symbols
• Organisms have at least 2 genes for most
  traits.
• Symbols are used to represent the
  combination of genes.
• An uppercase letter represents a
  dominant trait.
• A lowercase letter represents a recessive
  trait.


August 11, 2011                          123
                  Predicting Traits
• Punnett squares are charts that show
  possible gene combinations and the
  probability of each combination occurring.




August 11, 2011                            124
          Steps for creating a Punnett
                     Square
1. Draw a box with 4 squares in it.
2. Write the genes for the father across the
   top.
3. Write the genes for the mother down the
   side.
4. Fill in each square with the gene from
   the father.
5. Fill in each square with the gene from the
   mother.
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        Phenotypes vs. Genotypes
• The genotype is the specific genetic
  makeup (BB,Bb,or bb) of an individual, in
  the form of DNA .
• The phenotype of an individual organism
  is either its total physical appearance or a
  specific manifestation of a trait, such as
  size, eye color, or behavior that varies
  between individuals.

August 11, 2011                              130
• In other words, genotype is the genetic
  combination and phenotype is what it
  looks like.




August 11, 2011                             131
                  Assignment
• Complete worksheets 3-5 & 3-6.
• Complete Study guide 11-2
• Bikini Bottom Genetics




August 11, 2011                    132
                  Warm Up
•      Show a Punnett square that would result
       from the cross TT x tt. What would the
       genotypes and phenotypes of the
       offspring be?




August 11, 2011                              133
          How Well does a Punnett
          Square Predict the Actual
                  Ratios?
• Work with a partner to complete the
  punnett square lab




August 11, 2011                         134
                  Assignment
• Complete bikini bottom genetics 2 sheet




August 11, 2011                             135
                  Warm Up
• In rabbits, the allele for black fur is
  dominant over the allele for brown fur.
• A heterozygous black rabbit is crossed
  with a homozygous brown rabbit.
• Predict the possible genotypes and
  phenotypes of their offspring.
• Use a Punnett square to show your
  results.

August 11, 2011                             136
    What are incomplete dominance
          and codominance?




August 11, 2011                     137
              Incomplete dominance
• Incomplete dominance – offspring show a
  blending of traits from parent to parent.
• Neither allele is completely dominant over
  the other.




August 11, 2011                            138
                  Codominance
• Codominance – both alleles of a certain
  trait appear in the offspring.
• Neither allele is dominant over the other.
• Codominance does not involve blending.




August 11, 2011                            139
• Codominant and incomplete dominant
  crosses are sometimes shown with all
  capital letters. This shows that no
  particular trait is dominant over the other.




August 11, 2011                                  140
              Heterozygous crosses
• Recessive genes do not disappear
• They show up when heterozygous
  organisms are mated




August 11, 2011                      141
• If 2 heterozygous black and white
  chickens are mated – there will be a 25%
  chance of an offspring being BB.
• There will be a 50% chance of an offspring
  being BW
• There will be a 25%chance of an offspring
  being WW.
August 11, 2011                           142
                  Assignment
• Complete bikini bottom incomplete
  dominance
• Complete practice: codominance and
  incomplete dominance
• Complete genetics with a smile lab
• Complete worksheet 3-7



August 11, 2011                        143
                  Warm up
• In some horses, the allele for white hair ,
  W, is codominant with the allele for red
  hair, R.
• What is the chance of offspring with only
  red hair resulting from a cross between
  two heterozygous parents?
• Draw a Punnett square to show your
  results.
August 11, 2011                                 144
     How is Gender Determined?
• All humans have 23 pairs of
  chromosomes.
• In males, the 23rd pair of chromosomes is
  not alike.
• Male cells have one x chromosome and
  one y chromosome.
• The y chromosome is smaller than the x
  chromosome
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• Female cells have two x chromosomes in
  the 23rd pair.
• The x and y chromosomes determine the
  gender of an organism.
• Gender is the sex of an organism.




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                  Gametes
                  • Male cells have an XY pair
                    of chromosomes.
                  • During Meiosis, each
                    sperm cell receives only
                    one chromosome from
                    each pair.
                  • Every sperm cell contains
                    either an x or a y
                    chromosome.
August 11, 2011                             149
                  • Female cells have an
                    XX Pair of
                    chromosomes.
                  • During meiosis, each
                    egg cell receives one
                    chromosome from each
                    pair.
                  • All egg cells contain
                    only X chromosomes.
August 11, 2011                         150
                  Gender of Offspring
• The gender of offspring is
  controlled by the
  chromosome in the sperm
  cell.
• All children inherit their
  gender from their fathers.



August 11, 2011                         151
                  • If the sperm is carrying an
                    x chromosome, the
                    fertilized egg will have two
                    x chromosomes (xx) and
                    the baby will be a girl.




August 11, 2011                               152
• If the sperm is carrying
  a y chromosome, the
  fertilized egg will have
  one x chromosome and
  one y chromosome (XY)
  and the baby will be a
  boy.




August 11, 2011              153
        What are sex-linked traits?
• Some traits are inherited along with
  gender
• These traits are controlled by the x and y
  chromosomes.
• Traits that are inherited along with gender
  are called sex-linked traits.



August 11, 2011                             154
                  Sex-linked disorders
• Sex-linked disorders are more common in
  men, this is because sex-linked disorders
  are often recessive.
• Women have two x chromosomes, while
  one x chromosome might have the allele
  for a disorder, the other chromosome
  usually has a normal allele.
• Because the gene for the disorder is
  recessive, a female with each type of
  gene, still appears normal.
August 11, 2011                           155
• Colorblindness is a disorder in which a
  person cannot see the difference between
  certain colors.




August 11, 2011                          156
August 11, 2011   157
• Hemophilia is a disorder in which the
  blood does not clot properly




August 11, 2011                           158
                  Hemophilia
• Hemophilia is a sex linked
  disorder.
• A person with hemophilia
  lacks a special protein that
  allows blood to clot.
• Because it is a recessive
  trait, males generally have
  the disease, but females can
  be carriers.
August 11, 2011                  159
  Duchenne muscular dystrophy
• Duchenne muscular
  dystrophy is a genetic
  disorder caused by an
  error in the dystrophin
  gene.
• The condition causes
  progressive muscle
  weakness as the muscle
  cells break down and die.

August 11, 2011               160
              Male Pattern Baldness




August 11, 2011                       161
                  Warm Up
•   Define the following terms:
•   Sex-linked
•   Gender
•   Gamete
•   Karyotype
•   Chromosomes
•   X-chromosome
•   Y-chromosome
August 11, 2011                   162
                  Carriers
• Women who have normal gene and one
  gene for a sex-linked disorder are said to
  be carriers.
• They can pass the gene along to their
  children.




August 11, 2011                                163
                  Pedigrees
• Scientists study the traits of past
  generations in order to predict the traits of
  the offspring.
• They do this by making a chart, called a
  pedigree, that is similar to a family tree.
• Pedigrees show how certain traits are
  passed down from generation to
  generation.
August 11, 2011                               164
• A pedigree
  chart is a
  chart which
  tells one all
  of the
  known
  phenotypes
  for an
  organism
  and its
  ancestors.




 August 11, 2011   165
• Inbreeding or reproducing with members
  of your bloodline increases the risk of
  genetic abnormalities.
• Inbreeding has caused many breeds of
  dogs to have harmful genetic traits.
  Dalmatians are often deaf, and other dog
  breeds have high frequencies of epilepsy,
  blindness, and hip displaysia.
• It is true, that mutts are often hardier and
  have less health problems.

August 11, 2011                              166
            The Story of Hemophilia
• Late in the summer of 1818, a human sperm
  and egg united to form a human zygote. One of
  those gametes, we don't know which, was
  carrying a newly mutated gene. A single point
  mutation in a nucleotide sequence coding for a
  particular amino acid in a protein essential for
  blood clotting. The zygote became Queen
  Victoria of England and the new mutation was
  for hemophilia, bleeder's disease, carried on the
  X chromosome.
August 11, 2011                                  167
August 11, 2011   168
• Animal Pedigrees




August 11, 2011      169
                  Assignment
• Complete worksheets 3-9.
• Complete Pedigree chart
• Complete ancestors pedigree chart – use
  the information to create a pedigree chart
  using symbols, showing you and your
  siblings , your parents, grand parent, etc.



August 11, 2011                             170
                           Warm Up

• . The bison herd on Konza Prairie has begun to
  show a genetic defect. Some of the males have
  a condition known as "rabbit hock" in which the
  knee of the back leg is malformed slightly. This
  trait is a sex-linked gene and that is recessive.
  Now, suppose that the herd bull (the dominant
  one which does most of the breeding) who is
  normal (XN) mates with a cow that is a carrier for
  rabbit hock. What are his chances of producing
  a normal son?
August 11, 2011                                   171
1. If he mates with this cow every year,
   what percentage of their daughters have
   normal knees?
2. What percentage of their daughters will
   be carriers of rabbit hock?




August 11, 2011                          172
•      A woman with red-green color-blindness has a mother
       with normal vision. Knowing that color-blindness is a
       sex-linked recessive gene, can you determine what
       her father's phenotype is?
1.
       The woman marries a man with normal vision. What is
       the probability they will have sons who are red-green
       color-blind?

2.     What is the probability they will have daughters who
       are red-green color-blind?




August 11, 2011                                               173
•  A rancher owns a bull with many desirable
   characteristics. Unfortunately, he also has a sex-linked
   trait that in the recessive form leads to no pigment
   formation in the iris of the eye. This makes the bull very
   sensitive to sunlight and could lead to blindness. The
   rancher wishes to breed him to a cow that will minimize
   the chances of any offspring showing this trait. She
   would especially like to produce another bull with most
   of his sire's desirable qualities but without the
   nonpigmented eye. Two cows with the dominant normal
   colored eyes (XN) are available that have been
   genetically typed for this particular trait. Cow 1 has a
   genotype of XN XN and cow 2 is XNXn. Which of these
   two cows should the rancher choose as a mate to her
   bull if she wishes to minimize the occurrence of the
   nonpigmented eye in his offspring?
1. What percentage of the male offspring from the
   preferred cross will have nonpigmented eyes?

August 11, 2011                                            174
                  Assignment
• Complete Genetic smiley face lab in class.
  Hand in by the end of the period.
• Review text sections 14-1 and 14-2.
• Complete section review worksheets 14-1
  and 14-2.




August 11, 2011                           175
                  Warm up
•  Answer the following questions using
   complete sentences.
1. How can a female have the sex linked
   disorder of hemophilia? Use a Punnett
   square to explain your answer.
2. What kind of gene pair is found in the
   female carrier of a sex-linked disorder?


August 11, 2011                               176
           What are some inherited
                 diseases?
• Abnormal genes are sometimes passed
  from the parents to their offspring,
• A disease caused by an abnormal gene is
  called an inherited disease.




August 11, 2011                         177
                  Sickle Cell Anemia
• Sickle cell anemia is an
  inherited disease that
  mainly affects people of
  African descent.
• The red blood cells of a
  person with sickle cell
  anemia are crescent
  shaped

August 11, 2011                        178
• Sickle cells get easily trapped in blood
  vessels.
• They clog blood vessels and block the flow
  of blood
• The clogged blood vessels may cause
  severe pain, and in some cases death.




August 11, 2011                           179
• The gene for sickle cell is recessive (s).
• Normal red blood cells are dominant (S).
• People who inherit 2 recessive genes
  have the disease (ss).
• People who inherit one recessive gene are
  carriers of the disease (Ss).




August 11, 2011                           180
                   PKU
• Phenylketonuria, or PKU, is another kind of
  inherited disease caused by a recessive
  gene.
• People with PKU are missing an important
  enzyme that is needed to break down the
  amino acid , phenylalanine.



August 11, 2011                            181
                  • People with PKU
                    cannot eat certain
                    protein-rich foods
                    such as meats,
                    eggs, cheese and
                    milk.
                  • If people who have
                    PKU do not follow
                    their diet carefully,
                    the amino acid may
                    build up in the body
                    and cause brain
                    damage or mental
                    retardation.
August 11, 2011                             182
                  Tay-Sachs Disease
• Tay Sachs is a disease that affects mainly
  Jewish children with Eastern European ancestry.
• An abnormal gene stops the child‘s body from
  producing an enzyme that breaks down fat.
• The fat gathers in the brain cells.
• This can cause brain damage and death.
• Most children with this disease die before their
  4th birthday.


August 11, 2011                                 183
• A baby with Tay-Sachs disease appears
  normal at birth, but development starts to
  slow down at about 6 months of age.
  Gradually, the child becomes blind, deaf
  and paralyzed.
• The gene for Tay-Sachs is recessive.
• A person who is homozygous recessive
  (tt) inherits the disease.
• A person who is heterozygous (Tt) is a
  carrier.
August 11, 2011                                184
                  Huntington‘s disease
• Huntington‘s disease is caused by a
  dominant gene.
• The gene prevents the brain cells from
  functioning properly.
• The symptoms include loss of muscle
  control, mental illness, and death at an
  early age.
• Most people with this disease do not know
  they have it until they have already passed
  the gene onto their offspring.
August 11, 2011                            185
                  Genetic counseling
• Genetic counselors study family histories
  and interpret test results in order to predict
  the possible traits of offspring.
• Genetic counselors provide pregnant
  women with the information about their
  risk of having a baby with a genetic
  disorder.
• They also counsel children and adults
  about their own chances of developing a
  disease.
August 11, 2011                               186
                  Assignment
• Study guide 14-3
• Complete worksheet 3-10.
• Complete sickle cell article and questions.




August 11, 2011                             187
                  Warm up
• Read ―Tigers‖
• Finish article and questions




August 11, 2011                  188
   Conditions in the Environment
• The environment can change the way a
  trait is expressed.
• Heavy winds can cause trees to bend as
  they grow. Poor soil can cause plants to
  grow smaller than usual. These are called
  environmental influences.
• The environment can cause mutations in
  genes.
August 11, 2011                           189
             Environment and Traits




• The divi divi tree grows sideways because
  of the strong winds on the island of Aruba.

August 11, 2011                             190
                  Genetic Mutations
• A mutation is a change to the genetic
  material of an organism.
• A mutation can be harmful if it decreases
  the organisms ability to function properly.
• If the mutation occurs in the gametes of an
  organism, it can be passed on to the
  offspring.
• If the mutation only affects the body cells,
  the mutation is not usually passed on.
• Mutations can affect the single gene or the
  whole chromosome.
August 11, 2011                             191
                  Genetic Mutations




August 11, 2011                       192
August 11, 2011   193
                  Meningomyelocele




August 11, 2011                      194
                  Cleft lip




August 11, 2011               195
                  Webbed Toe




August 11, 2011                196
                  Progeria




August 11, 2011              197
August 11, 2011   198
                  Spina Bifeda




August 11, 2011                  199
                  Albinism




August 11, 2011              200
                  Marfan Syndrome




August 11, 2011                     201
   Dystrophic Epidermolysis Bullosa




August 11, 2011                   202
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August 11, 2011   208
• The clouded leopard, which makes its home on
  the Southeast Asian island of Borneo, was
  discovered to be a unique species. It is the
  island's largest predator.
August 11, 2011                              209
                  Assignment
• Complete worksheet 3-11
• Complete a painful decision
• Complete study guide 12-4




August 11, 2011                 210
                  Warm up
•  Answer the following question using
   complete sentences
1. Suppose a divi-divi tree was planted in a
   location with very little wind. What do you
   think it would look like?




August 11, 2011                             211
                  Controlled Breeding
• Mating organisms to produce offspring
  with certain traits is called controlled
  breeding.
• The offspring usually have the same
  desirable traits as their parents.
• Controlled breeding is used with livestock
  and plants.


August 11, 2011                            212
                  Mass selection
• In mass selection, plants with desirable
  traits are crossed.
• Seeds produced by the plants are
  collected and planted. New plants develop
  from these seeds.
• If the new plants have the desirable traits,
  then their seeds are collected and planted.
• The process goes on and on and
  eventually you will get a new kind of plant
  with desirable traits.
August 11, 2011                             213
• Mass selection is used to produce larger,
  more succulent strawberries.




August 11, 2011                               214
                  Hybridization
• Sometimes two organisms with different
  kinds of genes are crossed. The offspring
  show traits of both parents.
• The mating of different kinds of organisms
  is called hybridization.
• For example, wheat and rye plants can be
  crossed to create triticale, which is more
  nutritious then either wheat or rye.
August 11, 2011                            215
                  • A mule is a result
                    of hybridization.
                  • Its father is a
                    donkey and its
                    mother is a horse.
                  • Mules are sterile
                    and cannot
                    produced their
                    own offspring.


August 11, 2011                     216
                           ligers
                  • Ligers are prone to
                    gigantism; they are the
                    largest cats in the
                    world and can be
                    double the size of an
                    average adult Siberian
                    tiger.



August 11, 2011                           217
August 11, 2011   218
August 11, 2011   219
        Tigon
• from a male tiger
  and a female lion




August 11, 2011       220
                  Savannah




• from a domestic cat or Bengal cat and a
  serval


August 11, 2011                             221
              Coywolf
• from a coyote
  and a wolf -
  although rare, it
  can happen in
  the wild




August 11, 2011         222
                  Wolf Dog
• Happens often
  because dogs and
  wolves breed freely
• Their jaws are much
  stronger than those of
  a dog and are often
  used to exert
  dominance.


August 11, 2011              223
                  Iron Age pig
                        • Domestic Tamworth pigs
                          are crossbred with wild
                          boar to create ‗Iron Age
                          Pigs‘.
                        • The hybrids are tamer
                          than wild boar and
                          generally become
                          specialist pork sausages.
                        • Most of them are bred for
                          the specialist meat trade.


August 11, 2011                                   224
                      Zorse




   • A zorse is the result of crossbreeding a
     horse and a zebra.
August 11, 2011                                 225
                  Zonkey
                           • A zonkey is the
                             result of
                             crossbreeding
                             a donkey with
                             a zebra.




August 11, 2011                           226
                      Zony
   • The Zony is the result of crossbreeding a pony
     to a zebra.




August 11, 2011                                  227
                    Cama
• A Cama is a hybrid between a camel and a
  llama.
• They are born via artificial insemination due to
  the huge difference in sizes of the animals which
  disallow natural breeding.
• A Cama usually has the short ears and long tails
  of a camel but the cloven hooves of a llama.
• Also most noticeably is the absence of the
  hump.

August 11, 2011                                  228
August 11, 2011   229
August 11, 2011   230
                  grolar/pizzly
• A grolar/pizzly hybrid is the product of a grizzly
  bear and a polar bear.
• Although the two bears are genetically similar,
  they tend to avoid each other in the wild.




August 11, 2011                                        231
                  Leopon

                     • A Leopon is the result
                       of breeding a male
                       leopard and a female
                       lion.
                     • The head of the
                       animal is similar to
                       that of a lion while the
                       rest of the bodies
                       carries similarities to
                       leopards.
August 11, 2011                              232
                  Hybrid Pheasant




August 11, 2011                     233
August 11, 2011   234
                  Inbreeding
• Inbreeding is the mating of closely related
  organisms
• Offspring produced by inbreeding have
  genes that are very similar to their parent‘s
  genes.




August 11, 2011                              235
• Inbreeding is used to breed racehorses,
  whose desirable trait is speed.
• Inbreeding is done only with animals with
  desirable traits.


August 11, 2011                               236
    Why inbreeding is not allowed in
             most states




August 11, 2011                        237
• Mammals, most other animals, and higher
  plants as well, have evolved mechanisms
  to avoid inbreeding of any sort.
• Most pack animals (like lions, primates,
  and dogs), kick young males out of the
  pack so as to prevent them from mating
  with female relatives.




August 11, 2011                          238
                  Animal Breeding
• Animal Breeders study the genes that
  control certain traits in animals.
• They use this info to breed animals and
  produce offspring with desirable traits.
• For example, a thoroughbred race horse is
  bred for speed. A workhorse is bred for
  strength. A showhorse is bred for their
  ability to jump.

August 11, 2011                          239
                  Assignment
• Complete worksheet 3-12.
• Read genetic testing article.
• Create a written outline of the information
  in the article.
• Answer discussion questions ( counts as a
  quiz grade)



August 11, 2011                            240
                  Warm up
•  Answer the following questions using
   complete sentences.
1. Define mass selection, hybridization and
   inbreeding.
2. Why is inbreeding dangerous to an
   organism?
3. Would you rather have an inbred dog or
   a hybrid dog as a pet? Explain.

August 11, 2011                           241
                  Warm up
• If a genetic disorder were present in your
  family, would you go to a genetic
  counselor before having children? Why or
  why not?




August 11, 2011                            242
                  Genetic engineering
                              • Genetic
                                engineering is
                                the process by
                                which new
                                forms of DNA
                                are produced.



August 11, 2011                                  243
                  Gene Splicing
• Gene splicing is a process in which a
  section of DNA from one organisms is
  transferred to the DNA of another
  organism.




August 11, 2011                           244
  Gene Splicing creates a new DNA
               strand




August 11, 2011                 245
             3 steps of gene splicing
                       1. Dna ring is
                          temporarily opened
                          using certain
                          specific enzymes.
                       2. New genes from
                          another organism
                          are added, or
                          spliced, into the
                          DNA
                       3. The DNA ring is
                          closed.
August 11, 2011                            246
August 11, 2011   247
                  Benefits
1. Using gene splicing, bacteria can be
   used to manufacture human insulin.
2. Potential cures for genetic disorders
3. Improve traits in certain plants and
   animals used for food.




August 11, 2011                            248
                  • Scientists have
                    discovered a gene
                    that makes
                    corn resistant to
                    certain damaging
                    insects.



August 11, 2011                         249
• Thanks to genetic engineering, North Carolina
  soybeans can now be sprayed with Roundup,
  making weed control easier, less expensive, and
  safer for the environment.


August 11, 2011                                250
                  Disadvantages
1. Experimenting with bacterial DNA may
   cause a disease for which there is no
   cure.




August 11, 2011                            251
• Will we create
  things that look
  like this?




August 11, 2011      252
August 11, 2011   253
                   Cloning
• Cloning is the production of cells or organisms
  with identical traits.
• One way of cloning is to take the nucleus out of
  a cell from a donor animal.
• Then place the nucleus into an egg cell whose
  own nucleus has been removed.
• Then place the egg cell in the uterus of an
  animal and allow it to develop.
• When the baby animal is born, it is identical to
  the donor animal.

August 11, 2011                                  254
• Dolly, the first cloned
  sheep, was identical to
  her mother.
   August 11, 2011          255
• Clones can occur naturally in nature, a
  process called twinning. Identical twins
  are, in fact, clones.




August 11, 2011                              256
 What is the purpose of cloning?
• 1. Cloning for medical purposes
  2. Cloning animal models of disease
  3. Cloning stem cells
  4. Cloned genetically engineered animals
  for drug production
  5. Reviving endangered or extinct species
  6. Reproducing a deceased pet or child


August 11, 2011                           257
• Scientists often clone bacteria to make
  drugs.
• Cloning can also help produce animals
  with desirable traits.
• Scientists use cloned animals to study
  diseases.




August 11, 2011                             258
                  Assignment
•   Complete worksheet 3-13
•   Study guide 13-4
•   Complete section review 13-4
•   Complete genetic engineering enrichment




August 11, 2011                           259
                  Warm Up
• Solve the following problems
• In humans, the genes for colorblindness and
  hemophilia are both located on the X
  chromosome with no corresponding gene on the
  Y. These are both recessive alleles. If a man
  and a woman, both with normal vision, marry
  and have a colorblind son, draw the Punnett
  square that illustrates this. How many/what
  percentage of each could be expected?

August 11, 2011                              260
                  Cloning Humans
• Read the article ―South Korean Scientists
  Say they Cloned a Human Cell‖
• Answer the questions that follow in
  complete sentences.
• Be prepared to share.




August 11, 2011                           261
                  Homework
• Study for test tomorrow




August 11, 2011              262

				
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