Y Chromosome: Difference between revisions
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Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Males have one X and one Y chromosomes (46, XY) and females have a pair of [[X_Chromosome|X chromosomes]] (46, XX). | Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Males have one X and one Y chromosomes (46, XY) and females have a pair of [[X_Chromosome|X chromosomes]] (46, XX). | ||
* contains approximately 200+ genes | |||
* 50 million base pairs | |||
==Male Sex Determination== | ==Male Sex Determination== | ||
Revision as of 09:28, 14 March 2010
Introduction
Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Males have one X and one Y chromosomes (46, XY) and females have a pair of X chromosomes (46, XX).
- contains approximately 200+ genes
- 50 million base pairs
Male Sex Determination
Sry gene, found in 1990 on the Y chromosome, the sry gene encodes a "testis-determining factor" a 204aa protein (Mr 23884 Da).
Sry acts as a transcriptional activator (HMG type-high mobility group) binding to DNA and initiating male sex determination then regulating male development. The protein sequence is shown on this current page and the full genebank entry can also be seen. The sry protein has a HMG box that binds DNA by intercalating in the minor groove. Read about the mapping of the testis determining factor which is SRY.
The actual gene targets of SRY are still being determined but at least one downstream gene Sox9 has been identified. Another gene Dax1 (nuclear hormone-receptor superfamily member) when expressed as a transgene will antagonize Sry and also force dosage-sensitive sex reversal.
Links: X Chromosome | Y Chromosome | Week 1 Male Sex Determination (sry) | Genital System - Male
