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Principles of Inheritance and Variation question

2003 · Q71
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Principles of Inheritance and Variation question

2003 · Q71

NEETBiologyPrinciples of Inheritance and VariationMCQ+4 / −1
In Drosophila, the sex is determined by : -
  1. A
    X and Y chromosomes
  2. B
    Whether the egg is fertilized or develops parthenogenetically
  3. C
    The ratio of number of X-chromosomes to the sets of autosomes
  4. D
    The ratio of pairs of X-chromosomes to the pairs of autosomes
View written solutionFree

Correct answer: D

According to genic balance theory of sex determination the ratio between the number of X-chromosomes and number of complete sets of autosomes will determine the sex. The X-chromosome is believed to carry female tendency genes, while autosomes carry male tendency genes. Both these sets of genes start functioning and there has to be a balance between them for an individual to become male or female. If the ratio between X and A is 1.0 it will be a female individual and when it is 0.5, it would be male.

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