Question

If BB represents Barr body and ${Y_0}$ y-body, XXY or Klinefelters syndrome has.
A. BB – 1, ${Y_0}$ - 0
B. BB – 1, ${Y_0}$ - 1
C. BB – 0, ${Y_0}$ - 1
D. BB – 2, ${Y_0}$ - 1

Answer 1

Hint: Klinefelters syndrome: It is a genetic syndrome in which a male is born with an extra copy of the X chromosome. It is also known as 47, XXY. The primary features are infertility and small poorly functioning testicles.

Complete answer: Here, BB stands for Barr body whereas ${Y_0}$ represents the y- body. XXY is the form of Klinefelter syndrome which represents that male is born with one more additional X chromosome.
Barr body means that when one X gets inactivated and the number of this Barr body is always X minus 1.
For example in women or in females XX is present and in males XY is present.
Suppose in x we have ‘a’ gene so in females we have two copies of a gene whereas in males we have only one copy of gene ‘a’. If in females both X will be activated then, the product of them will be 2X but in males, it will remain single.
So, in females to make only a single copy any of the X becomes inactive and makes a normal gene product. The X which gets inactivated becomes the Barr body and the X will remain active.
In Klinefelter syndrome there is XXY, number of X is 2 so, and the Barr body will be the number of x minus 1 so, Barr body will be 2-1=1.
And the number of y chromosomes is 1.
So, the correct option is option B. BB-1, ${Y_0}$ -1.

Note: Symptoms are more prominent and may include weaker muscles, greater height, poor coordination, less body hair, breast growth, and less interest in sex.