How does meiosis contribute to genetic variation?

Meiosis contributes to genetic variation through independent assortment, crossing over, and random fertilisation.

Meiosis is a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell. This process is crucial for sexual reproduction and is responsible for the genetic diversity seen in populations. The three main ways meiosis contributes to genetic variation are through independent assortment, crossing over, and random fertilisation.

During the first division of meiosis, homologous chromosomes pair up and exchange genetic material in a process known as crossing over. This results in new combinations of genes on each chromosome. For example, a chromosome might have a gene for blue eyes from the mother and a gene for tall height from the father. This recombination of genes creates a unique combination of traits in each individual, contributing to genetic variation.

Independent assortment is another way meiosis contributes to genetic variation. This occurs when the homologous chromosomes line up along the middle of the cell during the first division of meiosis. The orientation of each pair of chromosomes is random, meaning that the daughter cells can end up with different combinations of maternal and paternal chromosomes. This random assortment of chromosomes leads to a vast number of possible genetic combinations in the offspring.

Finally, random fertilisation also contributes to genetic variation. This is the process where one sperm cell out of millions fertilises one egg out of thousands. The combination of these two cells, each with their unique set of genetic material, results in a zygote with a completely unique genetic makeup.

In conclusion, meiosis is a vital process that ensures the continuation of life by creating genetic diversity. Through crossing over, independent assortment, and random fertilisation, meiosis ensures that each individual is genetically unique, contributing to the variation seen in populations.