Sex Determination and Gonadogenesis Flashcards Preview

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Flashcards in Sex Determination and Gonadogenesis Deck (17):
1

Pseudoautosomal Region

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

2

TDF

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

3

TDF Sufficiency

TDF is sufficient to confer maleness.

4

Two results of TDF crossover

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

5

Sry

Sry expression is sufficient to confer maleness

6

What is Sry?

a transcription factor

7

Relationship between TDF, Sry, Sox9, Eif2s3x

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.

8

Indifferent Gonads

Indistinguishable stage of embryo development between males and females

9

Three important components during the indifferent stage

Sex Cords, Wolffian duct and Mullerian duct

10

Male Duct Differentiation

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

11

Female Duct Differentiation

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

12

What becomes the urinary and reproductive tract?

The cloaca

13

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

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

14

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

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

15

What are testosterone and DHT used for?

Secondary male characteristics.

16

AIS

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

17

What is the default expression without Wnt4a?

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