Question

While studying karyotypes, a student had drawn the karyotypes of two cells, one from an individual with Klinefelter’s syndrome (A) and the other from an individual with Down’s syndrome (B).
The difference between the number of chromosomes between A and B is _______.

• A. 2
• B. 1
• C. 3
• D. 0

Answer 1

The correct option is D 0

A technique that produces an image of an individual's chromosomes is called karyotype. In simple words, the picture of a person’s chromosomes is called karyotype.

Klinefelter’s syndrome and Down’s syndrome are examples of chromosomal disorders which are caused due to nondisjunction of X chromosome and autosomes respectively.

A male with Klinefelter’s syndrome has one extra copy of X chromosome, the karyotype is represented by 44+XXY. Hence, total number of chromosomes per cell = 47.

An individual with Down’s syndrome has trisomy of the 21st chromosome. Hence, total number of chromosomes per cell = 47.

The difference between the number of chromosomes between A and B, where A is Klinefelter’s syndrome and B is Down’s syndrome = 47 - 47 = 0.



Karyotype for Down's syndrome.