The Y Chromosome *PAR - Pseudoautosomal region *MSY – Male-specific region of Y *SRY – Sex...
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The Y Chromosome*PAR - Pseudoautosomal region
*MSY – Male-specific region of Y
*SRY – Sex determining region
*TDF - Testis Determining Factor
Is the Y chromosome a “genetic wasteland”?
SKALETSKY, et al. (2003) The male-specific region of the human Y chromosome is a mosaic of discrete sequence classes. Nature 423, 825 - 837
The Y Chromosome
The X Chromosome and Dosage Compensation*Do females produce twice as much of each gene product for X-linked genes?
Dosage compensation
*In mammals – X inactivation
*Barr and Bertram
*Susumo Ohno
The X Chromosome and Dosage Compensation*If you can make one copy of X (in females) inactive, you can compensate for dosage
Indirect evidence:
X Inactivation*Lyon hypothesis
Example:
Coat color in cats; G6PD in human fibroblasts
Avner, P. and Heard, E. (2001); X-CHROMOSOME INACTIVATION: COUNTING, CHOICE AND INITIATION, Nature Reviews Genetics 2; 59-67
Review: X inactivation
Mechanism of inactivation:
XIC or X-inactivation center
Sex determination in Drosophila:
Sex determination in Drosophila:
Temperature and sex determination: