Q163 / 180 · NEET 2015 (Phase 1) · Zoology

An abnormal human baby with 'XXX' sex chromosomes was born due to:

  • A
    Formation of abnormal sperms in the father
  • Correct answer
    B
    Formation of abnormal ova in the mother
  • C
    Fusion of two ova and one sperm
  • D
    Fusion of two sperms and ovum

Solution

Formation of abnormal ova i.e., 22 + XX in the mother will lead to birth of baby with 'XXX' genotype, due to chromosomal non disjunction in ova. Nondisjunction is the failure of the chromosomes to disjoin and move to opposite poles.

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

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