Imagine two populations of a gharial, one in the Chambal River and another in the Ganga. Now imagine two scenarios:
A) The populations breed separately. B) Adults of both populations migrate yearly to interbreed.
Which scenario would result in a greater loss of genetic diversity if the Chambal River population is driven to extinction by anthropogenic factors?
Options:

Correct option is A

Scenario A (populations breed separately): In this case, the two populations are isolated, and there is no gene flow between them. If the Chambal River population is driven to extinction, all its unique genetic material is lost forever, resulting in a significant loss of genetic diversity.
Scenario B (populations interbreed): In this case, gene flow occurs between the two populations, meaning the genetic material of the Chambal population is shared with the Ganga population. If the Chambal population goes extinct, the genetic diversity is less affected because the interbreeding ensures that the unique genes from the Chambal population are already present in the Ganga population.
Thus, Scenario A results in a greater loss of genetic diversity, as there is no genetic exchange between the populations.
Key Explanation: 1. Gene Flow and Genetic Diversity:
· Gene flow (migration and interbreeding) reduces genetic isolation, ensuring the preservation of genetic material across populations.
· In isolated populations, extinction events lead to irreversible loss of unique alleles.
2. Scenario A:
· Independent breeding populations are highly vulnerable to loss of genetic diversity due to lack of gene flow.
3. Scenario B:
· Interbreeding maintains genetic diversity across populations, buffering the effects of localized extinction.
Information Booster: 1. Genetic Drift:
· Small, isolated populations are more prone to genetic drift, where random changes in allele frequencies can lead to the loss of genetic variation over time.
2. Impact of Extinction on Genetic Diversity:
· In isolated populations, extinction wipes out all unique genetic traits.
· Interconnected populations retain genetic diversity due to gene flow.
3. Conservation Strategy:
· Encouraging gene flow between isolated populations can prevent the permanent loss of genetic diversity.
4. Anthropogenic Factors:
· Habitat destruction, pollution, and overexploitation often drive localized extinctions, as seen in river ecosystems like the Chambal and Ganga.
Additional Knowledge: · Scenario A (Breeding Separately): Isolated populations often develop unique genetic adaptations due to lack of gene flow. However, their genetic diversity is lost entirely if the population goes extinct.
· Scenario B (Interbreeding): Interconnected populations share genetic material, reducing the impact of localized extinctions. Gene flow prevents the loss of unique genetic traits.
· Genetic Diversity and Conservation:
· Genetic diversity is critical for species survival and adaptability to changing environments.
· Loss of diversity increases the risk of inbreeding depression and reduces evolutionary potential.