Determination of sex of an offspring is known as sex determination
Males have XY chromosome and Females have XX chromosomes. When a baby inherits the X chromosome from the father and the X chromosome from the mother, then the baby will be a female baby. When a baby inherits the Y chromosome from the father and the X chromosome from the mother, then the baby will be a male baby.
When you see the chromosomes, notice that it is the Y chromosome that determines the sex-linked inheritance of the baby. A mother i.e. a female has both XX chromosomes, whereas the father (male) has XY chromosomes. The Y chromosome of the male has a gene called SRY.
-In some animals, the temperature at which the fertilized eggs are kept decides the gender. Example: turtle.
-In humans gender of an individual is determined by a pair of chromosomes known as sex chromosome.
XX-Female / XY- Male
- in human beings there are 23 pair of chromosomes out of which 22 pairs of chromosomes are autosomes and 1 pair of chromosomes that determines the sex of an individual is known as sex chromosome.
-This shows that there is 50% chance of having a male offspring and 50% chance of having a female offspring.
-All the off springs will inherit the X chromosomes from the mother regardless of the gender.
- Thus sex of an individual is determined by what they inherit from their father, and not their mother.
Shaalaa.com | Sex Determination
Series 1: playing of 4
Write the types of sex-determination mechanisms the following crosses show. Give an example of each type.
(i) Female XX with Male XO
(ii) Female ZW with Male ZZ