Question

TDF gene is
A)A gene present on the x chromosome.
B)A segment of RNA
C)A proteinaceous factor
D)A gene present on Y chromosome

Answer 1

Hint: A DNA-binding protein (also known as the gene-regulatory protein/transcription factor) is the testis-determining factor (TDF). Mutations in this gene contribute to a variety of sex development disorders (DSD) with differing effects on the phenotype and genotype of a person.

Complete answer:
Testis-determining factor (TDF), also referred to as the protein for sex-determining region Y (SRY).

The SRY gene offers instructions for producing a protein called the protein of the sex-determining region Y. This protein is involved in the sexual growth of men, which is normally determined by the chromosomes that a person has. In cells, people typically have 46 chromosomes. Two of the 46 chromosomes, known as X and Y, are called sex chromosomes because they help decide if male or female sex characteristics will be formed by a human.

Girls and women normally have two X chromosomes (karyotype 46,XX), while boys and men generally have one X and one Y chromosome (46,XY karyotype).

The SRY gene is situated on the Y chromosome. The region Y protein formed from this gene acts as a transcription factor, which implies that it attaches (binds) to specific DNA regions and helps to regulate the activity of specific genes. This protein begins processes that cause a foetus to develop male gonads (tests) and prevent female reproductive structures from developing (uterus and fallopian tubes).

In the XY sex determination system, the Sry gene, located on the short branch of the Y chromosome, initiates male embryonic development. The Sry gene follows molecular biology's core dogma; the gene-encoding DNA is transcribed into messenger RNA, which then generates a single Sry protein. The Sry protein, a protein that initiates male development in humans, placental mammals, and marsupials, is also called the testis deciding factor (TDF).

Hence, the correct answer is option (D)

Note: The Sry protein is a transcription factor that can bind to testis-specific DNA regions, bend specific DNA and activate or enhance its ability to promote the formation of testis, marking the first phase in embryo development towards male rather than female development.