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Genetics by yurtgc548


									     Genetics 101

By: Wong Wei Cong (32)
Journey into DNA

The genome is here before us;
its chromosomes make me and you.
We see them here in their most condensed state,
each one will in no time be two.

Forty-six of them make up the genome,
half are mum’s and half are pop’s.
They’ll soon split into two when the cell divides;
there will be ninety-two when it stops.
Journey into dna

 We zoom in to take a close look at…
 a single chromosome?
 Didn’t we say there are two here?
 Half of this “X” is a clone.

 Chromosomes when stained show banding,
 or areas of light and dark.
 What causes this trait is its structure,
 and the denseness of its parts.
Journey into dna

  Here we behold a single gene,
  the unit of inheritance.
  If you’re short of thin or slim or bald,
  depends on its transmittance.

  Its length can vary greatly,
  its intricacy can’t be outdone.
  It can be as short as a hundred bases,
  Two million is a long one.
Journey into dna
 A DNA molecule is very long,
 when stretched out end to end.
 To fit inside a small cell
 it’s developed this knack to bend.

 The DNA twists ‘round and ‘round
 like countless Hula Hoops.
 It creates a cord-like structure,
 which we called chromatin loops.

 The chromatin scaffold is vital,
 providing much-needed support.
 From it extend many more loops
 that a ruler would measure as short.
Journey into dna
We almost see the DNA strand
as we look at some nucleosomes.
It’s wrapped tightly on those round things,
Which are structures called protein histones.

The histones, they carry a plus charge;
without it the strand’s in distress.
For then the DNA would try to float free,
And become a colossal mess.

“It has a helical structure,”
Watson and Crick forthrightly insisted.
With two sides and the rungs that connect them,
the DNA strand looks like a ladder that’s twisted.
Journey into dna

   Here is a small piece of the ladder,
   untwisted to better your view.
   Please note that the bases displayed here,
   are paired up in groupings of two.

   Note also that there are four letters;
   and that’s all that they’ll ever be.
   They comprise the four DNA bases,
   and they are A, T, C and G.
                        Development of life
                         -Darwin's theory of evolution

                                      Natural selection
                                      Adaptation
                                      Diversity
                                      Over-reproduction

 On the Origin of Species by
Means of Natural Selection, or
the Preservation of Favoured
Races in the Struggle for Life
                Development of life
                -Darwin's theory of evolution

 Natural selection              Development of antibiotic resistance
                                        in microorganisms
 Produces adaptations
 Biodiversity arises by
 surviving evolution
                     Development of life
                      -Darwin's theory of evolution

 All living organisms have a single common ancestor
 Each species through time fit somewhere in an
 evolutionary Tree of Life.

      Darwin’s Tree of Life                     Modern Tree of Life
                 Development of life
                -What Darwin didn’t know: Heredity

   Gregor Johann Mendel
   “Father of modern genetics”
   Australian monk & scientist
   Studied the inheritance of certain traits in pea plants
   Discovered the Laws of Inheritance
 Development of life
-What Darwin didn’t know: Heredity

                                     Parent plants
 Development of life
-What Darwin didn’t know: Heredity

          2nd Generation
 Development of life
-What Darwin didn’t know: Heredity


          3rd Generation
 Development of life
-What Darwin didn’t know: Heredity

                             Parent plants

                                     2nd Generation

   Development of life
  -What Darwin didn’t know: Heredity

DOMINANT                  RECESSIVE
 Development of life
-What Darwin didn’t know: Heredity
 Development of life
-What Darwin didn’t know: Heredity

                             Parent plants

                                     2nd Generation

 Development of life
-What Darwin didn’t know: Heredity
              Development of life
             -What Darwin didn’t know: Heredity

 Punnett Square
Development of life
-We have found the secret of Life

By 1953 Watson and Crick was on the case,
they were the dynamic duo that deciphered DNA.
Must be in double helix like a spiral staircase,
with Gs married to Cs and Ts paired to As.

We see here the famous arrangement
discovered by Watson and Crick.
Based on the work of Ms. Franklin,
Their model was at once declared slick.
Other genetic concepts

                           Multiple

                          Incomplete
Other genetic concepts

                          Co-dominance

                          Mutation?
        Weird Genetics-What is mutation?

 A change in genetic information
 Failure of DNA repair
 Mutate a sentence!
  – The fat cat ate the wee rat.
  – The fat hat ate the wee rat. (Point mutations)
  – The fat caa tet hew eer at. (Frame shift
  – The fat ate the wee rat. (Deletion)
  – The fat cat xlw ate the wee rat. (Insertion)
  – The fat tar eew eht eta tac. (Inversion)
          Weird Genetics-classification

 Hereditary mutations
 Acquired mutations

 Beneficial mutations
 (Murray Grey)
 Harmful mutations
 (Down Syndrome)
         Weird Genetics-classification

 Natural mutations
 Human intervention
  – Selective Breeding
  – Genetic Engineering
        Weird Genetics-selective breeding

 Breeding plants and animals for particular genetic
 traits (desirable characteristics)
 Inbreeding depression
 Reduced genetic diversity

                                         The Liger is the
                                         result of breeding
                                         a female Tiger to
                                         a male Lion.
        Weird Genetics-genetic engineering

Ian made a little lamb, little lamb, little lamb.
Ian made a little lamb and Dolly was her name.
When she grew, she was just like Mom.
Just like Mom, just like Mom.
Why was she just like Mom?
Their DNA’s the same!
                                   Weird Genetics-
                                   so what is GE?
   Selective change of genetic material by man
   Technique of removing, modifying or adding
   genes to a DNA molecule

Scientists successfully           ANDi (DNA inserted spelled
genetically engineered a rat to   backwards): The first
grow a human ear on its back.     genetically modified
                 Weird Genetics-
               gm food for thought
 Advantages:
  – Pest resistance
  – Herbicide tolerance
  – Disease resistance
  – Cold tolerance
  – Drought tolerance     Bright face of genetically modified corn
                          plant: pest-infected non-GM (left) and
  – Salinity tolerance    pest-free GM plant (right) planted side-by-
                          side in a field trial. (photo: Dr. Yu Jialin,
  – Nutrition             China Agricultural University)

  – Medicine
                 Weird Genetics-
               gm food for thought
 Disadvantages:
  • Environmental hazards
    o Unintended harm to other organisms
    o Reduced effectiveness of pesticides
  • Human health risks
    o   Unknown effects on human health
  • Economic concerns
    o   Corporate monopoly
    o   Dependence on GM companies
    o   Monoculture
                   Weird Genetics-
 Biotechnology critic Jeremy Rifkin: "It's the ultimate
 shopping experience: designing your baby.”
 Using genetic technologies to modify embryos and
 choose desirable characteristics
 Spare part children?
                     Weird Genetics-
                    the genetic menu

• EYE COLOUR         BROWN $10,000
                     BLUE $10,500
                     BLACK $9,500
• HAIR COLOUR        BLACK    $9,000
                     WHITE    $10,000
                     RED     $10,500
                     GREEN   $12,000 (MUST TRY!)
                             Weird Genetics-
                            the genetic menu
• SKIN TONE                 $9,50O
• WEIGHT/HEIGHT        $11,000

• BEAUTY          $20,000
• INTELLIGENCE    $23,000
• GENDER                     $19,500

                       Weird Genetics-
                      the genetic menu
• GREAT ARTIST                    $25,000
• GENIUS PHILOSOPHER              $26,000

• WORLD-CLASS SPORTSMAN           $25,000
• CANCER-FREE BABY                             $35.000

FOR FULL BABY MAKEOVER            $1,500,000
                                                         TERMS AND CONDITIONS APPLY
                       Weird Genetics-
                    terms and conditions?
 Safety issues
    – Genes introduced at random places in genome
    – Many genes have more than one effect
    – Many traits we want to select are influenced by multiple genes
   Environmental influence?
   Discrimination?
   Imbalance between rich and poor?
   Loss of humanity?
   Is it right to experiment on babies?
   Other moral complications?
     genetic blueprint- Human Genome Project

• Project goals
   – Identify all the approximately
     20,000-25,000 genes in human DNA
   – Determine the sequences of the 3
     billion chemical base pairs that
     make up human DNA
   – Store this information in databases
   – Improve tools for data analysis
   – Transfer related technologies to the
     private sector
   – Address the ethical, legal, and social
     issues that may arise from project
Thank y u!

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