Class 12 NEET Biology Principles of Inheritance and Variation Questions Part 1

Y-chromosome does not play any role in determination of sex in Drosophila. In human being, XXY is phenotypically male with underdeveloped testes, gynecomastia and often mental retardation. It is caused by the union of a non-disjunct XX egg and sperm and a normal X egg and abnormal XY sperm. This indicates that in human being Y chromosome is active in sex determination.