Summary
Differences in DNA among individuals, arising from mutation, recombination and sexual reproduction.
In depth
Mutation creates new alleles; meiosis shuffles them by crossing over and independent assortment; random fertilisation combines them. Variation is the substrate for natural selection and gives populations resilience.
Clonal organisms have little variation and are more vulnerable to disease.
Sources in sexual reproduction are crossing over (new allele combinations on a chromosome), independent assortment and random fertilisation; with them, no two siblings except identical twins are genetically the same. In bacteria, variation also comes from horizontal gene transfer by conjugation, transformation and transduction.
Variation is measured as heterozygosity, nucleotide diversity or number of SNPs: any two humans differ at about 0.1 percent of their DNA, one in 1000 bases, and most of this variation occurs within populations rather than between them.
Frequently asked questions
What is Genetic Variation?
Differences in DNA among individuals, arising from mutation, recombination and sexual reproduction.
Which area of biology covers Genetic Variation, and how advanced is it?
Genetic Variation is one of the 54 topics in Genetics. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Gene Pool, Crossing Over, Allele.
Why does Genetic Variation matter?
Without variation a population cannot adapt, and low diversity, as in cheetahs, makes it vulnerable to disease.
Can you give an example of Genetic Variation?
The Irish potato famine devastated genetically uniform potato crops.
What should I learn before Genetic Variation?
Genetic Variation is a Beginner topic, so no earlier topic is required. Other Beginner topics in Genetics that pair well with it include Heredity, Gene, Allele.
What topics are related to Genetic Variation?
The closest topics to Genetic Variation are Gene Pool, Crossing Over, Allele, Genetic Drift. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Genetic Variation?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Genetic Variation. To practise the whole of Genetics, use the Genetics quiz.
How is Genetic Variation different from Gene Pool?
Genetic Variation: Differences in DNA among individuals, arising from mutation, recombination and sexual reproduction. Gene Pool: The total collection of alleles in all individuals of a breeding population. Read both side by side and note what each one explains.
How should I study Genetic Variation step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Gene Pool and explain the difference aloud. Finally, take the Genetics quiz and come back to this page for any question you miss.