Question

Identify mutations that have altered sexual development. How do you expect the following mutations to affect sexual development (more males/more females)?
a. A disabling mutation in the WNT4 coding sequence.
b. A disabling mutation in the DMRTI coding sequence.
c. A mutation in the FGF9 binding site on the WNT4 gene

Answer 1

Answer:

Option B

Explanation:

DMRTI gene is a protein responsible for regulating Sertoli cells and germ cells. It performs the function of testicle development in gonads during the sex determination period. Normal sexual development requires two copies of this gene.

Sertoli cells -> help in sperm-formation

Germ cells -> sex-cells

A disabling mutation in the DMRTI coding sequence causes a male-to-female sex reversal after sex determination. The deletion of this gene can cause male infertility as well.

Answer 2

Answer:

a. WNT4 protein is encoded by the WNT4 gene it is located in the chromosomes. WNT4 is responsible for the development of female features, while inhibiting the male development. Mutation of WNT4 gene will result in the Rokitansky-Kuster-Hauser syndrome.

b. Located in the 9th chromosome, DMRT1 (Doublesex and mad-3 related transcription factor 1) is the protein encoded by DMRT1 gene, it is responsible for the regulation of the gonadal sex distinction, thus sex (male) determination in multicellular eukaryotes. Mutation of this gene results in the deletion of 9p chromosome, causing abnormal testicular formation since the DMRT1 protein is found in the testicular cord and seritoli cells.

c. FGF9 promotes male sex development. Mutation causes an XY sex reversal.

Explanation: