Question

A village population somewhere in South East Asia contained 5 alleles at a locus on a chromosome in the recent past before 80% of the population was killed by a huge earthquake. Ten years after the earthquake, it was found that two rare alleles were no longer found in this population. The population genetic reason for the decrease of diversity is most likely due to

Answer 1

The loss of rare alleles in a Southeast Asian village population after an earthquake is attributed to genetic drift and the bottleneck effect, which reduced genetic diversity and increased the risk of inbreeding depression.

Step-by-step explanation:

The decrease in genetic diversity due to the loss of two rare alleles in a village population after an earthquake in South East Asia is most likely due to genetic drift and the bottleneck effect. An earthquake is a natural disaster that can cause a massive and random reduction in a population, significantly affecting the population's genetic variance. Subsequently, the survivors contribute their genes to the subsequent generations, potentially leading to changes in allele frequencies and loss of genetic diversity if those survivors do not carry the rarer alleles.

In small populations, genetic drift and the bottleneck effect can have a profound impact on genetic variation and lead to inbreeding depression. The population can become more vulnerable to environmental changes and diseases due to decreased genetic variability. The catastrophic event in this case acted as a non-selective pressure, eliminating alleles irrespective of their contribution to fitness.