Question

A pregnant human female was advised to undergo mtp. it was diagnosed that thefetus she was carrying had developed from a zygote having 45 chromosomes withonly one x chromosome.

a) what is this condition called and how does it arise?

Answer 1

Turner syndrome is the result of an aneuploid condition, specifically monosomy, where a fetus has 45 chromosomes with one X chromosome due to nondisjunction during meiosis resulting in missing or extra chromosomes in the gametes.

Step-by-step explanation:

The condition described, where a fetus has a total of 45 chromosomes and only one X chromosome, is known as Turner syndrome. This arises due to aneuploidy, specifically a form of monosomy found in the sex chromosomes. Aneuploidy occurs when there's an error in chromosome number during the formation of gametes, usually due to nondisjunction during meiosis.

As a result, a gamete may be missing a chromosome; when such a gamete is fertilized, the resulting zygote will have an abnormal number of chromosomes. In the case of Turner syndrome, the affected individual typically has one X chromosome instead of two, leading to a variety of developmental challenges and sterility. While most monosomic conditions lead to non-viable pregnancies, Turner syndrome individuals can survive but may experience issues such as short stature, webbed neck, and cardiac abnormalities.