Q27.2-1CC - Campbell Biology

Question

Although rare on a per gene basis, new mutations can add considerable genetic variation to prokaryotic populations in each generation. Explain how this occurs.

Step-by-Step Solution

Answer

The rapid accumulation of a mutation in the prokaryotic population is due to the shorter generation time of these microscopic organisms and the large size of their population.

Step 1: Mutation

The term mutation describes the condition in which the genetic sequence of an organism gets altered either due to some external factors (like chemical agents) or due to some error in the replication mechanism. It is also one of the causes of genetic diversity.

Step 2: Prokaryotic reproduction

Prokaryotes are unicellular and reproduce asexually; this means that prokaryotic offspring inherit the genome without any variation. Since their reproduction is similar to cell division, it completes in a short span of time. This accounts for their large population in a very short time.

Step 3: Rapid addition of mutation and genetic diversity

The asexual mode of reproduction ensures that if by chance the parental genome gets mutated, then that mutation is carried to the offspring generation. As the rate of reproduction in prokaryotes is high, these organisms multiply very rapidly.

 

Thus, the mutated genome gets rapidly copied to a large fraction of the population, and it gets established within the population in a short span of time.