C2005/F2401 '09 -- Outline for Lecture 20

Last posted/updated 11/22/09 05:12 PM

I. Wrap up of Karyotypes -- Aneuploidy (Handout 19B)

II. Overview of Meiosis (Handout 19C)

III. Steps of Meiosis (Handout 19A)

IV. Life Cycles  (Handout 20 -- top)

V. Nondisjunction  -- how mistakes in meiosis cause aneuploidy  (Handout 20 -- bottom)

VI. Inactive X's and Barr Bodies. Why extra X's are tolerated but extra autosomes are not.

     A. Lyon Hypothesis -- inactivation of "extra" X chromosomes

    B. Barr bodies -- seeing the inactive X

    C. How X inactivation was detected  -- orange and black cats; Introduction to genetic terminology:

        heterozygous, homozygous, loci, alleles

    D. When & how Barr body forms

VII. Intro to Patterns of Inheritance