what is sex determination?? pls explain for class 12
Answers
sex determination is nothing but the fusion of gamates takes place it leads to pregnancy...
Explanation:
Females in humans have 2X chromosomes- 1 each is inherited from either parent and denoted as XX. Males in humans have 1X and 1 Y chromosome, where the X is inherited from the mother and the Y from the father. In a way, we can say that it is the father who determines the sex of the unborn child. This can put to shame a lot of history in which people believed it is the woman who was responsible for not giving birth to a male heir. We can also say that the absence of the Y chromosome makes the individual a female.
At the time of spermatogenesis in males, both types of gametes are produced- one carrying the X chromosome and one carrying the Y. At the time of fertilization, the sex of the resulting zygote will depend on which gamete of the father will fuse with the X of the mother. We can, therefore, say that there is a 50% chance that the child will be a male and 50% that it can be a female.
Types of sex determination
The XX-XY system as seen in human beings, where, XX is the female and XY is the male. This is also seen in a few insects.
The ZW-ZZ system as seen in birds, where, ZW is the heteromorphic female and ZZ is the homomorphic male. This is also seen in some fishes and few insects.
