chp 5

Question 1

How to y chromosome works

Answer 1

1. Testis-determining factor produced by the sry gene on y chromosome.
2. TDF induces medualla of embryonic gonads to develop into testes.
3. Testes produce testosterone, which initiates development of male sexual characteristics

Question 2

How lack of y chromosome works

Answer 2

1. no TDF produced in absense of y chromosome
2. lack of TDF allows cortex to develop into ovaries
3. in absense of testosterone, embryo develops female sexual characteristic

Question 3

mechanisms of dosage compensation

Answer 3

Hyperactivation(crank up) of x linked genes in males. (Drosophila)
Inactivation of one copy of x linked genese in females
Down regulation of x-linked genes in females