A fruit fly is heterozygous for sex linked genes, when mated with normal female fruit fly, the males specific chromosome will enter egg cell in the proportion:
Correct answer: C. 1 : 1
- A. 3 : 1
- B. 7 : 1
- C. 1 : 1
- D. 2 : 1
Explanation
The female Drosophila possesses two homomorphic sex chromosomes (XX) and the male Drosophila contains two heteromorphic sex chromosomes (XY). The differential or non homologous region of the Y-chromosome is mostly heterochromatic. The female parent produces only one type of egg (22 + X). The male parent produces two types of gametes (22 + Y) and (22 + X). They are produced in equal proportions. As the two types of sperms are produced in equal proportions, there are equal chances of getting a male or female fly in a particular mating.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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