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Wonders of Human Biology
What is the role of DNA in inheritance?
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Deoxyribonucleic acid plays a crucial role in inheritance . It is the hereditary material which passes information from one generation to another . DNA is made of nitrogen base, sugar and phosphate backbone . When this genetic information is passed from the parent to an offspring (one generation to another ) and hence it is known as inheritance. The basis for this lies in the fact that DNA makes genes and genes make chromosomes. Humans have 23 pairs of chromosomes – a total of 46 chromosomes. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair is called the sex chromosomes and differs between males and females. Females have two copies of the X chromosome or XX, while males have one X and one Y chromosome.
Both parents have reproductive cells – sperms in fathers and ovum or eggs in mothers. These sperms and eggs contain half the number of chromosomes – 23 each. When the egg and the sperm fertilizes, this gives rise to a cell that has the complete set. Thus a person inherits half of his or her genes from each of the parents.