Meiosis and Genetic Diversity

Genetic diversity is vital for the survival and adaptation of species, and meiosis is a crucial process introducing diversity among organisms.
Meiosis is a type of cell division that produces gametes, or sex cells (sperm and eggs), each with half the number of chromosomes as the parent cell.
Every round of meiosis contributes to significant genetic variation among offspring and in the population.

Crossing Over in prophase I of meiosis I mixes genetic information between two homologous chromosomes. Specific arms of these chromosomes exchange segments, creating new combinations of genes.
Independent Assortment occurs in metaphase I when the homologous chromosomes line up randomly at the cell’s equator. This leads to multiple possible combinations of chromosomes in each gamete.
Random Fertilisation further increases genetic diversity. When an egg and a sperm – each with their unique combination of chromosomes – combine, they create a new, genetically unique individual.

Genetic diversity allows populations to adapt to changes in the environment, enhancing survival.
The unique combination of genes in each individual contribute to phenotypic variation – differences in physical characteristics – among members of a species.

Sometimes, errors can occur during meiosis, leading to chromosomal abnormalities.
One such error is nondisjunction, where chromosomes fail to separate correctly. This results in gametes that have either too many or too few chromosomes.
Nondisjunction can cause genetic conditions such as Down syndrome, Turner syndrome, and Klinefelter syndrome.

The genetic diversity that meiosis contributes to populations fuels evolution.
Natural selection acts on the genetic variation present, favouring those individuals with traits that provide a survival advantage.
Over time, the favourable traits increase in frequency in the population, leading to evolutionary changes.