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In fruit flies, The X:A ratio determines whether the sex-lethal protein (Sxl) is

ID: 174784 • Letter: I

Question

In fruit flies, The X:A ratio determines whether the sex-lethal protein (Sxl) is produced. This ultimately determines the gender of the fruit fly. How is this accomplished?

Sxl binds the gonad identity recognition locus (GIRL) promoter and activates the genes required for the development of a female fruit fly.

When Sxl is not expressed, the Tra gene is alternatively spliced, resulting in a non-functional Tra protein. This produces a male fruit fly.

Sxl binds the mRNA for GIRL, and prevents its translation, resulting in a male fruit fly.

If Sxl is not produced, the embryo remains haploid resulting in a female fruit fly.

a.

Sxl binds the gonad identity recognition locus (GIRL) promoter and activates the genes required for the development of a female fruit fly.

b.

When Sxl is not expressed, the Tra gene is alternatively spliced, resulting in a non-functional Tra protein. This produces a male fruit fly.

c.

Sxl binds the mRNA for GIRL, and prevents its translation, resulting in a male fruit fly.

d.

If Sxl is not produced, the embryo remains haploid resulting in a female fruit fly.

Explanation / Answer

When Sxl gene not expressed,result in non functional tra gene.due to nonfunctional tra gene ,dsx gene produce male specific proteins,lead to male phenotype.