Question

Which of the following best describes why XXY human males are viable, yet not completely wild-type?One of their X-chromosomes is converted to a Barr body, but their Y-chromosome is not. Many cells in their body are euploid (either XX or XY), because 3 chromosomes cannot be partitioned into 2 daughter cells in a meiotic division. One of their X-chromosomes is converted to a Barr body, however, they have three copies of each of the pseudo-autosomal regions, which are not dosage compensated. The Y-chromosome is small but does encode a few genes, such as SRY.

Answer 1

Ans. One of their X-chromosomes is converted into a Barr body. The viability of human males can be describe on the basis of Lyon hypothesis, which states that in cells with multiple X chromosome one will be active another will be inactive and this process happen during mammalian embryogenesis.

In another case (euploid), some cells will be normal and some cells will be abnormal. Which can affect the viability of human males.