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NEET2016ZoologyPrinciples of Inheritance and VariationActual

Assertion : XX-XY type of sex determination mechanism is an example of male heterogamety. Reason: In birds, male heterogamety is seen as males produce two different types of gametes.

Options

  1. AIf both assertion and reason are true and reason is the correct explanation of assertion.
  2. BIf both assertion and reason are true but reason is not the correct explanation of assertion.
  3. CIf assertion is true but reason is false.
  4. DIf both assertion and reason are false.

Correct answer

C. If assertion is true but reason is false.

Step-by-step solution

Chromosomal or allosomic determination of sex is based on heterogamety or occurence of two types of gametes in one of the two sexes. Male heterogamety is found in allosome complements XX-XY and XX-XO. In birds and some reptiles both the sexes possess two sex chromosomes but unlike human beings the females contain heteromorphic sex chromosomes ( AA + ZW ) while the males have homomorphic sex chromosomes (AA + ZZ ).

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