Question

Indicate the expected number of Barr bodies in interphase cells of individuals with Klinefelter syndrome; Turner syndrome; and karyotypes 47,XYY, 47,XXX, and 48,XXXX.

Answer 1

Answer:

Barr bodies are small bodies that are dark staining bodies that show the inactivated X chromosome, these sex chromatin bodies attach to the membrane of the nucleus of interphase cells.

One less of the total number of X-chromosome (n-1) represents the number of Barr bodies.

Then,

The number of Barr bodies with Klinefelter would be:

Klinefelter (47,XXY): (n-1) = (2-1) = 1 Barr body as here two X chromosome present.

Similarly, for

Turner (45,XO): (n-1) = (1-1) = 0 Barr bodies (X chromosome = 1)

Now, as per the question, the bar bodies for karyotypes given

47,XYY: (n-1) = (1-1) = 0 Barr bodies

47,XXX: (n-1) = (3-1) = 2 Barr bodies

48,XXXX: (n-1) = (4-1) = 3 Barr bodies