Biochemistry 4463G Chapter Notes - Chapter 6 (Part-2): Oligospermia, Nondisjunction, Gonadal Dysgenesis

• School: Western University
• Department: Biochemistry
• Course: Biochemistry 4463G
• Professor: Peter Rogan

Document Summary

Chapter 6: the chromosomal and genomic basis of disease. The fundamental basis of the xx/xy system of sex determination become apparent with the availability of cytogenetic analysis: Males with klinefelter syndrome had 47 chromosomes with the additional chromosome being an extra x (47,xxy karyotype) Turner syndrome in females on the other hand had only 45 chromosomes due to an x- monosomy (45,x karyotype). While sex chromosomes play a determining role in specifying chromosomal and gonadal sex, a number of genes found in both sex chromosomes and autosomes are also involved in sexual differentiation. In male meiosis, the x and y chromosomes normally pair by segments at the ends of their short arms, and undergo recombination at that region: Pairing includes pseudo-autosomal regions where the x- and y-linked copies are essentially identical; undergoes recombination in meiosis i the way autosomes do. Relatively gene-poor (<100 genes, some of which belong to multi-gene families)