Q161 / 180 · NEET 2019 (All India) · Zoology

Select the incorrect statement.

  • A
    Male fruit fly is heterogametic.
  • B
    In male grasshoppers, 50% of sperms have no sex-chromosome.
  • Correct answer
    C
    In domesticated fowls, sex of progeny depends on the type of sperm rather than egg.
  • D
    Human males have one of their sex-chromosome much shorter than the other.

Solution

1) The male fruit fly has XY sex chromosomes and produces two types of gametes. Hence, it is called heterogametic.

2) The female grasshopper is XX and the male XX-XO systems produce gametes with (X) or without (O) a sex chromosome. Hence, in male grasshopper, 50% of sperms have no chromosome.

3) Birds have a ZW sex-determination system. The sex of the embryo is determined by the egg in birds and not by the sperm. However, it is written here that the sperm decides the sex of the progeny. 

4) In humans, the Y chromosome is considerably smaller than the X chromosome and has a much lower density of genes. In fact, the Y has often been called a genetic junkyard.

Hence, the correct answer is option: 'C'.

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