Genetic Diversity
What is genetic diversity?
Genetic diversity refers to the total number of characteristics in the genetic makeup of a species. Each species is made up of individuals that have their own particular genetic composition. Within a species there may also be discrete populations with distinctive genes.
How is it important to the survival of a species?
Genetic diversity is important to the survival of a species because it codes for variations of phenotypes, some of which may better suit the individual organism to a particular environment than others, therefore giving it an increased chance of survival.
Mutation
What is mutation?
Mutation is a change in the genetic code in DNA than can lead to a change in the protein that is coded for and produced by that segment of DNA. This can change an organism's characteristics for the good or for the bad.
What causes mutations?
Mutations can be caused by a few factors. These include environmental factors (e.g. sunlight, smoking, radiation) and errors during DNA replication.
Different types of mutations.
- Insertion - Extra base pairs inserted into a new place in the DNA.
- Deletion - A section of the DNA is lost, or deleted.
- Substitution - Exchanges one base for another.
- Frameshift - The insertion or deletion of a number of bases that is not a multiple of 3.
- Missense - Changes the codon to a different amino acid.
- Nonsense - Changes the codon to read a stop codon instead of an amino acid.
- Point - A change to a single base pair.
- Silent - A change that does not affect the protein sequence.
Relationship between mutations and genetic diversity.
Mutations are a common cause to genetic diversity within a species.
How meiosis contributes to variation
Variation can occur during meiosis due to crossing over sections of maternal and paternal chromosomes, and also due to the independent assortment of the chromosomes into gametes.
Gene flow
Gene flow, also called migration, is the movement of individuals, and/or the genetic material they carry, from one population to another. Gene flow provides another source of diversity within a population. Emigration (moving out) may result in the loss of particular alleles, immigration (moving in) may result in the addition of new alleles into the population. Immigration and the introduction of a new genetic trait into a population can sometimes be good or bad.