Ques. 1AIPMT 2001
Male XX and female XY sometime occur due to
- Aneuploidy
- Deletion
- Transfer of segments in X and Y chromosomes
- Hormonal imbalance
Answer
(3) Transfer of segments in X and Y chromosomes
Solution
In humans maleness is decided by the testis-determining gene (SRY) present on the Y chromosome.
During meiosis in the father, an abnormal exchange (translocation) of segments between the X and Y chromosomes can carry the SRY region to the X chromosome.
An XX individual receiving such an X therefore develops as a male (XX male), while an XY individual whose Y has lost this segment develops as a female (XY female).
∴ XX males and XY females arise due to transfer of segments between X and Y chromosomes.
Answer: (3)