with the help of a flow chart explain in brief how the sex of a newborn is genetically determined in human beings . which of the 2 parents the mother or father is responsible for determination of sex of a child?
Answers
The sex of a baby is determined by the type of male gamete that fuses with the female gamete.
All human beings have 23 pairs of chromosomes in their nuclei. Out of these 23 pairs, the last pair is known as the sex chromosome.
The human males have 23 pairs of chromosomes including XY sex chromosomes. Therefore, the male gamete has 22 chromosomes and either an X or Y sex chromosome.
Male gametes can be of two types: 22+X or 22+Y
Females have 23 pairs of chromosomes including XX sex chromosomes. Therefore, their gametes can only have 22 chromosomes and one X sex chromosome.
Type of female gametes: 22+X
Thus, as the mother provides only X chromosome, the sex of the baby is determined by the type of male gamete (X or Y) that fuses with the X chromosome of the female.
therefore, father is responsible for determination of sex of a child.
The explanation and the flow chart is given below:
- The sex of the newborn is determined at the time of fertilization.
- A human male has a set of XY sex chromosomes. Thus it can produce two types of sperms, one with an X chromosome and the other with a Y chromosome.
- A human female however has a set of XX chromosomes. Thus it can produce ova of only a single type.
- If the X sperm fuses with the ovum, the fetus will have an XX genotype and will be a girl.
- If a Y sperm fuses with the ovum, the fetus will have an XY genotype and will be a boy.
- Hence, from the above statements, it is clear that the father is responsible for the determination of the sex of a child.
