Question

In a population, group of individuals of similar phenotypes are formed because of differential reproduction due to

• A. Genetic drift
• B. Natural selection
• C. Migration
• D. Selective hybridization

Answer 1

The correct option is A Genetic drift

• In differential reproduction, some individuals of the same species reproduce more offspring and some reproduce only few.
  
• For example - we have a very small rat population that comprises of 8 brown individuals (genotype BB or Bb) and 2 white individuals (genotype bb).
• Initially, the frequencies of the B (0.5) and b (0.5) alleles are equal.
• But purely by chance, only the 5 individuals (all have brown coat color) in the rat population reproduce, i.e. differential reproduction.
  
• Because of this, in the second generation frequency of the B allele increases (as more rats are now brown colored) while the frequency of the b allele is decreased.
• After a few generation, only brown-colored rats (similar phenotype) will be found in that population.
• This change in allele frequencies in a population from generation to generation that occurs due to chance events is called genetic drift.

Therefore, the correct answer is option A.