Question

Define genetic diversity.

Answer 1

Genetic diversity can be simply explained by explaining the two terms genetic meaning anything that refers to the genes and diversity meaning the variation. The variation is mainly at the level of DNA which gets transcribed to mRNA and then the effect is shown at the level of proteins after translation.

Complete answer:
Genetic diversity in simple terms is the different types or variation of genes that are present in a population or in a given species. It can be said that the genetic diversity is a result of recombination in the genetic material as it leads to diversity or variation in the genetic makeup of the organisms. Sexual reproduction is the most important factor that contributes to genetic diversity. The other factors that are responsible for producing diversity in the genes is the mutation of the genes, genetic drift and gene flow.

Mutation is a sudden change in the base sequence of the DNA. This can happen due to various reasons such as UV light exposure, exposure to chemical mutagens etc. This causes a change in the genetic diversity of the species as the mutation can even be inherited if it happens in the germ cells.

Genetic drift is the change in the allelic frequency of a gene/allele in a population over the course of time. It can simply be defined as the genes that can be lost from a population or a new gene that can be introduced into a population when an organism moves out or into a population respectively. For example, if organism A is the only individual in a population that contains a specific gene and the organism moves out of the population into another population, then the gene is totally removed from the gene pool of the first population and the gene is drifted away. This causes the decrease in the genetic diversity or variation in the population.

Gene flow is the flow of genes from one population to another. This can happen when an organism moves from one population to another contributes its genes to the new population.

Additional information:
Genetic diversity is important for the organisms for a number of reasons. Variations in the gene pool helps the organisms to adapt to different environmental pressures that can be present and plays a role in the survival of the organisms. This is certainly useful for the organisms but can pose a threat to other organisms as well. The best example is the genetic diversity seen in viruses and the difficulty of making a vaccine against them. The viruses like HIV have mutations in every replicative cycle and hence it has a different genetic content for every cycle.

Note: Gene pool is the total collection of all the genes in a population. Selective breeding causes the loss of certain wild genes or alleles and only conserves the alleles that are required for humans. The examples are selective breeding of dogs, cross breeding of plants and animals etc. Although in most of the cases the human intervention has led to the loss of many wild type alleles, in some cases humans have shuffled some organisms to get a better genetic diversity as in the case of Florida panthers which was suffering from inbreeding depression which had led to the decline of the panthers because of the weak alleles.