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Which one of the following conditions correctly describes the manner of determining the sex in the given example?
A
Homozygous sex chromosomes (XX) produce male in $Drosophila$
B
Homozygous sex chromosomes (ZZ) determine female sex in birds
C
XO type of sex chromosomes determine male sex in grasshopper
D
XO condition in humans, as found in Turner Syndrome, determines female sex
Detailed Solution
Grasshopper has XO type sex determination: females have a pair of X chromosomes (XX) and males have only one X chromosome (XO), so XO determines the male sex. This is correct.
In $Drosophila$, XX individuals are females and XY individuals are males.
In birds the females are heterogametic (ZW) and the males are homogametic (ZZ), so ZZ determines the male sex.
In humans sex is determined by the XX–XY mechanism; XO (Turner's syndrome) is an abnormal condition (a sterile female with rudimentary ovaries) and is not the manner in which female sex is normally determined.
Hence the correct description is that the XO type determines male sex in grasshopper.
In $Drosophila$, XX individuals are females and XY individuals are males.
In birds the females are heterogametic (ZW) and the males are homogametic (ZZ), so ZZ determines the male sex.
In humans sex is determined by the XX–XY mechanism; XO (Turner's syndrome) is an abnormal condition (a sterile female with rudimentary ovaries) and is not the manner in which female sex is normally determined.
Hence the correct description is that the XO type determines male sex in grasshopper.