Question

A population of manatees in Florida was recently affected by a harmful algal bloom that reduced their population size from 1,000 to 250, and the effects of the algae bloom have left many of the remaining females sterile. The manatee haploid genome size is approximately 3.7x10^9bp (remember that manatees, like most animals, are diploid), and the rate of mutation occurrence is 2x10^-7 mutations/site/generation.

How many new mutations are predicted to occur in the functional region (10%) of the genome each generation?

As the population of manatees gets smaller due to nonreproducing females, explain how the effects of genetic drift increase and the effects of natural selection decrease?

Answer 1

Manatees or sea cows : these are fully aquatic, herbivorous, marine mammals come to water surface for breathing, weigh about 400-590 kgs and grow up to 13 feet in length.

Algal blooms: Rapid increase in algal population which are microscopic in nature in aquatic habits. When there are abundant sources of Nitrogen and phosphorous available it triggers the growth of algae, they contain biotoxins which are harmful to aquatic life including larger animals like whales and manatees.

Genetic drift: It is a mechanism in which the allele frequencies of a certain population change over time, in coming generations such that the population can survive in extreme conditions also.it normally happens in all populations but its effectsare rapidly seen in small populations.

the bottle neck principle tells us that when populations are too low to survive in a habitat which is destroyed by natural calamities, killing most of individuals leaving a small assortment of the group, then the stress to survive can cause mutations immediately along with changing environmental factors.

Factors of why genetic drift is minimal in manatees:

Larger population are unlikely to change quickly when compared to small populations, the mutation rate serves as "molecular clock", the overall mutation rate doesn't change very much in bigger animals and also larger number of mutations especially in mammals are seen in males than in females, so if the above case if all male manatees die, then possible chance of other manatees wiped out comes true.

the mutations that originates should be beneficial for the population to grow, and should be emerged from functional gene,which can act as genome re-sequencing tool.

EX: In an Ecoli of 5* 10⁷ bps one mutation in every 1000 generations occurs, but in stressed conditions this can be applicable to even larger animals by artificial invitro methods it can be done.In humans we arrive at about 0.1 - 1 mutations for every 10,000 replications.