Genetic Drift

Source-This post on Genetic Drift is based on the article “Genetic drift, not natural selection, identified as main factor driving speciation in endangered pupfish species” published in “PHYS.ORG” on 22nd May 2024.

Why in the News?

Scientists have discovered a new species within the genetic family of an endangered pupfish native to south-central New Mexico. The emergence of two species from the White Sands pupfish is notable because it was primarily driven by genetic drift.

About Genetic Drift

1. About Genetic Drift: Genetic drift is a fundamental evolutionary mechanism. It occurs when there are random fluctuations in the frequencies of alleles (different forms of a gene) within a population over time.

2. Mechanism of Genetic Drift: The process is driven by random sampling of alleles and random events affecting individual survival and reproduction. Changes in allele frequencies reflect these random variations.

3. Impact on Population Genetics: Smaller populations are particularly vulnerable to genetic drift because their smaller gene pools are less able to withstand random changes. Genetic drift can result in an allele becoming either fixed (the only allele present at a locus) or lost within the population, reducing genetic diversity.

4. Genetic Drift and Population Bottlenecks: Population bottlenecks is significant reductions in population size due to events like natural disasters which can intensify genetic drift. This can lead to the loss of rare alleles and a reduction in the overall genetic diversity.

5. Genetic Drift’s Role: Genetic drift can cause a new population to become genetically distinct from its original population. This divergence can contribute to the evolution of new species.

Comparison with Natural Selection:

a) Unlike natural selection, which involves traits that improve survival and reproductive success, genetic drift is the result of chance.

b) Natural selection operates when individuals with advantageous traits reproduce more successfully, gradually changing the gene pool and characteristics of the population.

c) Genetic drift lacks selection pressure; it does not favor specific traits, thus affecting populations randomly without regard to the fitness of the organisms.

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