In: Biology
On several occasions I mentioned the term standing genetic variation in the context of how natural populations are better able to adapt to environmental change. This is important for species to cope with climate change, especially for rare and endangered species. What does standing genetic variation have to do with adaptation? (Which best explains it?)
Standing genetic variation is an approximation of artificial selection for MHC allele variants.
Individuals with more variation present in their genomes are
favored by natural selection following an environmental change, and
the population adapts via an overall increase in genetic variation
in the population because the most genetically variable individuals
have highest fitness.
A population adapts to environmental change by the rise to high frequency of an existing genetic variant that was already present in the population at low frequency before the environmental change.
A population adapts to an environmental change by the occurrence of a beneficial mutation in an individual that introduces genetic variation, which rises to high frequency in the population because it is favored by natural selection following the environmental change.
Genetic variation becomes costly for individuals following an environmental change, and the result is that overall genetic variation in a population decreases as the population adapts to the environmental change.
The best explanation for standing genetic variation is given below.
Genetic variation becomes costly for individuals following an environmental change, and the result is that overall genetic variation in a population decreases as the population adapts to the environmental change.
[In a population different individuals have different genetic sequences. Due to climate change/environmental change there is a reduction in the genetic variation as well as the ability of a species to evolve in response to environmental changes. Natural selection acts on genetic variation. There is an increase in the frequency of those gene that are advantageous in a species'. Adaptation will not occur if the right gene aren't present in a population. Due to decreased genetic variation, the survival and reproductive rates also reduces through inbreeding depression .]