Question

Explain the sex determination mechanism in humans. How is it different in birds

Answer 1

1 / 1


prasanna
Aug '16
Sex determining mechanism in humans is XY type. Out of 23 pairs of chromosomes present, 22 are autosomes.A Pair of X chromosomes is present in females, whereas an X and Y chromosome are present in males.During spermatogenesis among males,two types of gametes are produced.
2.50 percent of the total sperm produced carry the X chromosome and the rest 50 percent has Y chromosome.In5 case, the ovum fertilizes with the sperm carrying X chromosomes the Zygote develops into female (‘XX’) and with ‘Y’ chromosomes the zygote results into male offspring(XY).
In birds, female birds have been designated to have Z and W chromosomes, whereas males have a pair of Z chromosomes besides autosomes.
hope it helps plse mark as brainliest

Answer 2

Explanation:

Solution :

In human beings, females are homogametic with X chromosomes only with genetic composition of XX while males are heterogametic with genetic composition of XY. An egg in the female will bear only X chromosome . In males, half the sperms bear X chromosome and the other half bear Y chromosomes. When the X bearing sperm fertilizes the egg, it results in XX forming a female zygote and when a sperm bearing Y chromosome fertilizes the egg, it results in XY condition forming a male zygote. In birds, ZW and ZZ system is followed. Female birds are heterogametic with Z and W chromosomes while male birds are homogametic carrying Z chromosomes in their sperms. In both humans and birds, *** chromosomes are along with the autosomes. In humans, males have 44+XY chromosomes and females have 44+XX chromosomes.

PLS MARK AS BRAINLIEST