Sex Determination and Gonadogenesis

Question 1

Pseudoautosomal Region

Answer 1

A region with sufficient homology to allow crossovers between X and Y chromosomes

Question 2

TDF

Answer 2

Testis determining factor: a region that can be carried along with the pseudoautosomal region in rare cases

Question 3

TDF Sufficiency

Answer 3

TDF is sufficient to confer maleness.

Question 4

Two results of TDF crossover

Answer 4

Either XX , but with testes; or XY, but not external male features

Question 5

Sry

Answer 5

Sry expression is sufficient to confer maleness

Question 6

What is Sry?

Answer 6

a transcription factor

Question 7

Relationship between TDF, Sry, Sox9, Eif2s3x

Answer 7

TDF is a region that builds Sry, a transcription factor, and Eif2s3y, a translation initiation factor. Sry leads to Sox 9 expression from the autosome.

Question 8

Indifferent Gonads

Answer 8

Indistinguishable stage of embryo development between males and females

Question 9

Three important components during the indifferent stage

Answer 9

Sex Cords, Wolffian duct and Mullerian duct

Question 10

Male Duct Differentiation

Answer 10

Wolffian duct : vas deferens; Sex cords: seminiferous tubules; Mullerian duct: eventually degenerates

Question 11

Female Duct Differentiation

Answer 11

Wolffian duct degenerates;Surface epithelium–>surface of ovary, Mullerian duct: oviduct/fallopian tube

Question 12

What becomes the urinary and reproductive tract?

Answer 12

The cloaca

Question 13

Male Gonadal Differentiation [factor,3 components,4 chemicals, degeneration]

Answer 13

Sry leads to Sox9 expression, formation of testes, leydig cells, and sertoli cells. Lydia cells create testosterone which is converted by 5alpha reductase to Dihydrotestosterone. Sertoli cells secrete anti mullerian duct hormone

Question 14

Female Gonadal Differentiation [factor,3 components,4 chemicals, degeneration]

Answer 14

Wnt4 expression creates Ovary, Thecal cells, and Granulosa cells. Theca cells create testosterone, and Granulosa cells produce aromatase, which converts Testosterone to Estrogen.

Question 15

What are testosterone and DHT used for?

Answer 15

Secondary male characteristics.

Question 16

AIS

Answer 16

Androgen Insensitivity Syndrome [testosterone & dihydrotestosterone] mutation in the androgen receptors. Female outer phenotype, but with male internal organs.

Question 17

What is the default expression without Wnt4a?

Answer 17

Testes formation, or at least more male like than females. no ovaries.