Question

Meiosis is important for evolution because of

• A. Recombination in somatic cells.
• B. Number of chromosomes in somatic cells become half.
• C. Formation of diploid eggs (gametes).
• D. Equational and reductional divisions.

Answer 1

The correct option is D Equational and reductional divisions.

Meiosis produces haploid gametes. The haploid gametes are produced after crossing over between non sister chromatids of homologous chromosomes. This gives rise to new combinations of genetic material and creates diversity which ultimately is acted upon by natural selection. The meiosis occurs in two stages: meiosis I or reductional division and meiosis II or equational division. The reductional division is important for generating diversity and reducing the number of chromosomes to one half. The equational division is important for splitting of centromere and separation of sister chromatids, else the gametes will have double or bivalent chromosomes and when these gametes fuse the zygote will have all duplicated chromosomes even before the S phase. This will ultimately result in excess DNA and genetic mutations such as polyploidy.