Genetic variation

Sources of Genetic Variation

• Random mutations are the ultimate source of genetic variation.
• Crossing over and random segregation during meiosis can produce new alleles.
• Polyploidy is an example of chromosomal mutation.

Forms and Measurement of Genetic Variation

• Genetic variation can be small-scale sequence variation or large-scale structural variation.
• Recombination by transposable elements and endogenous retroviruses contributes to genetic variation.
• Numerical variation in chromosomes can be polyploidy or aneuploidy.
• Genetic variation within a population is commonly measured as the percentage of polymorphic gene loci.

Maintenance and Impact of Genetic Variation

• Harmful recessive alleles can be hidden in heterozygous individuals.
• Natural selection maintains genetic variation in balanced polymorphisms.
• Balanced polymorphisms occur when heterozygotes are favored or when selection is frequency dependent.

Historical Perspectives and Concepts of Heritable Variation

• Maupertuis and Diderot built on Lucretius’ idea of random creation.
• Darwin attributed variation to environmental forces and gemmules.
• Mendel’s heterozygosity concept became fundamental in genetic variation.
• Fisher introduced variance, foundational to modern statistics.

Applications and Further Study of Genetic Variation

• Genetic diversity and variability are key areas of study.
• Human genetic variation is a significant field of research.
• Cheetahs are known for their low genetic variability.
• Population bottlenecks have implications for genetic variation.
• Understanding genetic variation is crucial in various fields.

Genetic variation Data Sources