NEETZoologyPrinciples of Inheritance and Variation
The diploid somatic chromosome number in a female bird of a particular species is 78 . What will be the exact chromosome composition of the ova produced by this bird?
Options
- A39 A + Z and 39 A + W
- B38 A + X and 38 A + Y
- C76 A + Z and 76 A + W
- D38 A + Z and 38 A + W
Correct answer
D. 38 A + Z and 38 A + W
Step-by-step solution
Birds exhibit the ZZ-ZW type of sex determination, where females are heterogametic (possessing one Z and one W chromosome) and males are homogametic (ZZ). The given diploid chromosome number ( 2n ) of the female bird is 78 . This total includes both autosomes and sex chromosomes. Number of autosomes = Total chromosomes - Sex chromosomes = 78 - 2 = 76 autosomes ( 76 A ). During meiosis, the chromosome number is halved to form haploid gametes (ova). The 76 autosomes segregate equally, resulting in 38 autosomes ( 38 A