Question

In the nucleus of a somatic cell from a Klinefelter (47,XXY) syndrome individual, you are likely to find:

1) 0 Barr body
2) 1 Barr body
3) 2 Barr bodies
4) 3 Barr bodies

Answer 1

In the nucleus of a somatic cell from someone with Klinefelter syndrome (47,XXY), you would find 1 Barr body, as one of the two X chromosomes is inactivated to balance gene expression.

Step-by-step explanation:

In the nucleus of a somatic cell from an individual with Klinefelter syndrome (47,XXY), you are likely to find 1 Barr body. The presence of the Barr body indicates that one of the two X chromosomes has undergone inactivation, which is a biological mechanism to compensate for the excess genetic dosage.

Klinefelter syndrome is a condition where males have an extra X chromosome (XXY instead of the typical XY). In these individuals, all but one of the X chromosomes are inactivated to balance the gene expression levels. Since individuals with Klinefelter syndrome have two X chromosomes and one Y chromosome, there would be just one Barr body present in the nucleus of each somatic cell, corresponding to the inactivated X chromosome.

Turner syndrome, on the other hand, involves an XO genotype, where the individual has only one sex chromosome, an X, with no Barr bodies present.