GRS4101 Lecture Notes - Lecture 1: Loose Connective Tissue, Y Chromosome, Fetus
24 Jul 2018
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Definition of sex: chromosomal sex, genetic sex, gonadal sex, phenotypic sex, behavioural sex, legal sex (defined by phenotypic sex). Female has 22 pairs of autosomes and a pair of x chromosomes: 46 xx. Karyotype 46 xx: normal female phenotype: male has 22 pairs of autosomes and y chromosome: 46, xy. 45xo: turners syndrome (f) always phenotypically female which suggests is default mode. 47xxy: klinefelters syndrome (m): suggests power of y chromosome. Femaleness is the default mode, if presence of y chromosome person is phenotypically male, therefore there must be genes on the y chromosome that say: make testis. Sex reversal: xy female (y chromosome is missing, or mutation = sry deletion), xx male (xx males contain sry gene had been translocated to the x chromosome). The above reversal occurs by crossing over at prophase one of sry from y to x.
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