Choose the set of sex determining chromosomes that indicates the correct sex of the respective organism.
Homozygous sex chromosomes (ZZ) determine female sex in birds
XO type of sex chromosomes determine male sex in grasshoppers
XXY condition in humans, as found in Turner Syndrome, determines male sex
Homozygous sex chromosomes (XX) produce male sex in Drosophila
XO type of sex chromosomes determine male sex in grasshoppers
The correct option is: XO type of sex chromosomes determine male sex in grasshoppers.
To understand why this option is correct, let us analyze the sex determination mechanisms in different organisms:
1. Grasshoppers (XO sex determination system):
In grasshoppers, the male sex is determined by an XO system. Females have two X chromosomes (XX), making them homogametic. Males have only one X chromosome and no corresponding sex chromosome (represented as XO), making them heterogametic. The presence of a single X chromosome determines the male sex. Therefore, the statement "XO type of sex chromosomes determine male sex in grasshoppers" is correct.
2. Birds (ZW sex determination system):
In birds, females are heterogametic with ZW chromosomes, whereas males are homogametic with ZZ chromosomes. Thus, homozygous sex chromosomes (ZZ) determine the male sex in birds, not the female sex.
3. Humans (Turner Syndrome):
Turner Syndrome in humans is characterized by an XO genotype (having only one X chromosome, 45,X), which determines a female phenotype, not male. An XXY condition in humans is known as Klinefelter Syndrome, which results in a male phenotype.
4. Drosophila (Fruit flies):
In Drosophila, sex is determined by the ratio of X chromosomes to autosomes. Females have homozygous sex chromosomes (XX), and males have XY. Thus, XX produces female sex, not male.