Question

How does meiosis contribute to genetic variation in a speciation?

Answer 1

Meiosis is important because it ensures that the correct number of chromosomes is contained in all organisms created by sexual reproduction.

Complete answer:
Meiosis also induces genetic variation by means of the recombination process. Later, as two gametes combine during fertilization, this variation is increased even more, thereby producing offspring with special DNA combinations. In sexual reproduction, this persistent mixing of parental DNA helps drive the remarkable diversity of life on Earth.

During the entire meiosis process, there are two divisions that occur, resulting in haploid cells. You start with a cell called diploid (2n) and end with 4 (n) haploids. Two stages occur, Meiosis I and Meiosis II.

The genetic variation portion: A rare occurrence occurs during Prophase I of Meiosis I, called crossing over.

During synapsis, the replicated homologous pairs of chromosomes join together. Here, chromosome pieces are shared.The end result involves chromosomes, which maximise genetic diversity, including genes from both parents.The synapsis and crossing process occurs only in sexual reproduction (meiosis).

Meiosis contributes to the development of gametes in somatic body cells, which have half the number of chromosomes. This implies that for a new person to develop, two gametes should fuse together. Two people bear characteristics of the two gametes from two separate parents, and this is the first source of difference.

During metaphase I, the process of independent assortment takes place when the chromosomes from both parents align separately on the equator of the cell, indicating some on one side of each parent, and the opposite on the other. This suggests that there is a mixture of chromosomes produced by the parents of the gamete, and this is the second source of variation.

Finally there is the crossing over which occurs even in metaphase I where genetic material between the homologous chromosomes is exchanged. This means that not the whole parental chromosome goes to one cell in this one chromosome, but rather a mixture of both the paternal and the maternal goes to one cell, and the other goes to the opposite mixture. And this is the third cause of variance.

Note: Independent assortment is the mechanism where the chromosomes travel randomly to different poles during meiosis. After meiosis, a gamete will end up with 23 chromosomes, but the separate assortment ensures that each gamete will have 1 of several different chromosome combinations.