Phytochrome Can Interconvert between Pr and Pfr Forms

TLS Online TPP Program

#Id: 1012

#Unit 5. Developmental Biology

In mammals, the bipotential gonad appears to be moved into the male pathway (testis development) by the Sry gene (on the Y chromosome), which triggers the activity of Sox9.

TLS Online TPP Program

#Id: 1013

#Unit 5. Developmental Biology

The testis makes two major hormones involved in sex determination-

-Anti-Müllerian hormone (AMH), causes the Müllerian duct to regress.

-Testosterone, causes differentiation of the Wolffian duct into the male internal genitalia.

TLS Online TPP Program

#Id: 1014

#Unit 5. Developmental Biology

A fruit fly’s sex is determined predominantly by the number of X chromosomes in each cell.

TLS Online TPP Program

#Id: 1015

#Unit 5. Developmental Biology

A fly have two X chromosomes and three sets of autosomes, it is a mosaic.

TLS Online TPP Program

#Id: 1016

#Unit 5. Developmental Biology

In Drosophila, the X chromosome contains genes encoding four transcription factors that activate the critical gene in Drosophila sex determination, the X-linked locus Sex-lethal (Sxl).

TLS Online TPP Program

#Id: 1017

#Unit 5. Developmental Biology

Three major RNA targets to which the female-specific Sxl transcript binds: 

Pre-mRNA of Sxl itself

msl2 gene

pre-mRNA of transformer (tra)