What is sex- determination ? State the various methods of sex determination in animals.
Dear Student
Biologically humans are categorised into male and female. Before the birth of child, determining the sex of the child through the technologies available today is known as sex determination. This is very prevalent in Indian society since boys are preferred over girls. But this act is banned by the government.
Sex determination in humans:
Human beings exhibit male heterogamy. In humans, males (XY) produce two different types of gametes, X and Y. The human female (XX) produces only one type of gametes containing X chromosomes. The sex of the baby is determined by the type of male gamete that fuses with the female gamete. If the fertilizing sperm contains X chromosome, then the baby produced will be a girl and if the fertilizing sperm contains Y chromosome, then the baby produced will be a boy. Hence, it is a matter of chance that determines the sex of a baby. There is an equal probability of the fertilizing sperm being an X or Y chromosome. Thus, it is the genetic make up of the sperm that determines the sex of the baby.
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Sex Determination in birds:
The sex chromosomes in birds is determined as Z and W. The male is homomorphic (ZZ) and the female is heteromorphic (ZW). W chromosome carries female sex determining genes and duplication of Z chromosome indicates male sex. So, in case of chicks, the sex is determined by teh egg and not by the sperms.
Sex determination in Snails:
​In snails, sex is determined by a method known as sequential hermaphroditism (i.e. every individual first acts like a male and later as female).It is affected by location of the organism. In this, larvae settles down on a substratum and act as males. New individuals pile up over this and allows the males at the bottom to become females. All the younger individuals are males.
Also, once a male is changed to a female, it cannot revert back to a male.
Regards
Biologically humans are categorised into male and female. Before the birth of child, determining the sex of the child through the technologies available today is known as sex determination. This is very prevalent in Indian society since boys are preferred over girls. But this act is banned by the government.
Sex determination in humans:
Human beings exhibit male heterogamy. In humans, males (XY) produce two different types of gametes, X and Y. The human female (XX) produces only one type of gametes containing X chromosomes. The sex of the baby is determined by the type of male gamete that fuses with the female gamete. If the fertilizing sperm contains X chromosome, then the baby produced will be a girl and if the fertilizing sperm contains Y chromosome, then the baby produced will be a boy. Hence, it is a matter of chance that determines the sex of a baby. There is an equal probability of the fertilizing sperm being an X or Y chromosome. Thus, it is the genetic make up of the sperm that determines the sex of the baby.
​
Sex Determination in birds:
The sex chromosomes in birds is determined as Z and W. The male is homomorphic (ZZ) and the female is heteromorphic (ZW). W chromosome carries female sex determining genes and duplication of Z chromosome indicates male sex. So, in case of chicks, the sex is determined by teh egg and not by the sperms.
Sex determination in Snails:
​In snails, sex is determined by a method known as sequential hermaphroditism (i.e. every individual first acts like a male and later as female).It is affected by location of the organism. In this, larvae settles down on a substratum and act as males. New individuals pile up over this and allows the males at the bottom to become females. All the younger individuals are males.
Also, once a male is changed to a female, it cannot revert back to a male.
Regards