BIOLOGY 1A03 Lecture Notes - Lecture 2: Homologous Chromosome, Y Chromosome, Meiosis
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30 Mar 2016
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BIOLOGY 1A03 Full Course Notes
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Biology 1a03 theme 5 module 3 and 4. X and y chromosome (y is much smaller) Female will carry two x chromosomes (one from each parent) Male will develop from a gamete that carries both an x and y chromosome. Only small regions at the ips of the x and y chromosomes allow for these chromosomes to pair and segregate like homologous chromosomes during meiosis. 78 genes on the y chromosome that code for about 25 proteins (and half of these genes help determine sex) Most of the 1100 genes on the x chromosome have many funcions that are unrelated to sex determinaion. A gene that is located on either sex chromosome is oten referred to as a sex- linked gene because expression of the phenotype may depend on the sex of the individual. An ishihara colour test is one of the most common ways to test for red/green colour-blindness.