HUMAN GENETICS AND HUMAN HEALTH

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					                  BIOL 202                          When and where will class meet?

                                                    Mondays: meet at 2:00 in
         HUMAN GENETICS                                      Lawson Room 101

              AND
          HUMAN HEALTH


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When and where will class meet?
Most Wednesdays:
Section 1 meets at 2:00 in Lawson Room 101
Section 2 meets at 2:00 in Life Science II
                                                    www.biologicalsciences.siu.edu/biol202/
                           Room 450
Section 3 meets at 3:00 in Life Science II
                          Room 430
On February 22 and April 5, all sections meet
 at 2:00 in Lawson 101 (on syllabus).
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                                                                       Overview

                                                       I Pedigrees
                                                       II Single Gene Disorders
                                                       III Complex Traits
                                                       IV Chromosomal Disorders


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I Pedigrees                                            II Single Gene Disorders

                                                       What is the mode of inheritance?
A pedigree is the history of a trait in a family
diagrammed in symbols.                                 Two important questions are:
                                                         Is it dominant or recessive?
                                                         Is it autosomal or sex-linked?


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II Single Gene Disorders                          II Single Gene Disorders
1. dominant vs. recessive                         1. dominant vs. recessive

Example: there are two forms of a gene            Example: there are two forms of a gene
   which is needed to make a pigment--               which is needed to make a pigment--
         functional, nonfunctional                         functional, nonfunctional
Humans have two copies of (most) genes.           Humans have two copies of (most) genes.
   1) functional, functional                         1) functional, functional--pigmented
   2) nonfunctional, nonfunctional                   2) nonfunctional, nonfunctional--albino
   3) functional, nonfunctional                      3) functional, nonfunctional--??
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II Single Gene Disorders                          II Single Gene Disorders
1. dominant vs. recessive                         1. dominant vs. recessive

Example: there are two forms of a gene               1) functional, functional--pigmented
   which is needed to make a pigment--               2) nonfunctional, nonfunctional--albino
         functional, nonfunctional                   3) functional, nonfunctional--pigmented
Humans have two copies of (most) genes.               One copy of the functional form of this
                                                         gene is enough to be expressed.
   1) functional, functional--pigmented
   2) nonfunctional, nonfunctional--albino        The functional form of this gene is dominant
   3) functional, nonfunctional--pigmented         to the nonfunctional form, which is recessive.
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II Single Gene Disorders                           II Single Gene Disorders
1. dominant vs. recessive                          1. dominant vs. recessive

By convention upper case symbol is used for        A term:
    the dominant form.
If we use the symbols A and a (for albino) the        An allele is an alternate form of a gene
    symbols for these three gene combinations
    are:
                                                             example: A and a
                     AA
                      Aa
                      aa
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II Single Gene Disorders                           II Single Gene Disorders
1. dominant vs. recessive                          2. autosomal vs. sex-linked

Two more terms:                                    Two types of chromosomes:
                                                    autosomes (22 pairs)
Genotype refers to the genes an organism has.
                                                    sex chromosomes (1 pair)
Phenotype refers to the observable traits of an
   organism.                                       Karyotype: picture of chromosomes arranged
                                                              in order, largest to smallest
                                                                   females 46,XX
                                                                   males 46,XY
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II Single Gene Disorders
                                                  III Complex Traits
Four modes of inheritance:

   autosomal dominant                            Conditions which do not follow a simple

   autosomal recessive                           pattern of inheritance can be called

   sex-linked dominant                           complex traits.

   sex-linked recessive

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IV Chromosomal Disorders                          Other topics

extra or missing or structurally abnormal        Molecular genetics
    chromosome                                   Population genetics
                                                 Genetic testing
Example: an extra chromosome 21                  Cancer
                   47,+21                        Biotechnology, the Human Genome Project,
                                                    Cloning
                                                 Treatment of genetic disease
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