In this article, we will discuss the sex determination in human beings. This is an important topic in biology and questions are frequently asked from this topic.
- In a human being, we determine the sex with the help of the sex chromosome i.e. with the help of X and Y chromosome.
- In a human being, 46 chromosomes are found out of which 44 are found in 22 pairs called autosomes and the other two chromosomes are called sex chromosomes.
- The rest two chromosomes are the same in females and are called X- chromosomes (XX).
- In a male, the rest two chromosomes are different and are called X and Y chromosomes.
- During reproduction females produce one type of gametes and containing 22 autosomes and one X chromosomes, while males produce two types of gametes one have 22 + X type chromosomes and others have 22+ Y types of chromosomes.
- When male gametes i.e. sperm carrying X chromosomes fertilizes an ova, the zygote develops into a female.
- When a sperm carrying Y chromosomes fertilizes an egg, Zygote develops into a male.
Some Genetic Disorder occurs due to Chromosomes:
- When a male has an extra X or Y chromosome in sex chromosomes then the condition will be XXY or XYY instead of XY. The individual became sterile in this condition.
- In female when an extra X chromosome is present instead of XY they show normal development but limited fertility, metal retardness is also seen in this type of syndrome.
- When female has single-sex chromosome (X0) their ovaries are rudimentary, lack of secondary sexual characteristics.
When an extra chromosome is added to 21st autosomal chromosomes this lead to develop Down’s syndrome.
- This disorder leads to failure to distinguish between red & green colour.
- The gene responsible for this disease is situated on sex chromosomes.
- This type of syndrome is developed by addition of autosomal chromosome in 13th chromosome.
- There is a cut mark in the lip and the person is mentally retarded.
Number of Chromosomes in Different Organisms:
No. of Chromosomes
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