Question

How does genetic drift affect the survival of the human population?

Answer 1

Genetic drift is the change in the frequencies of an existing gene in a population due to random sampling of organisms. It can help or harm the organism and affect its survival.

Complete answer:
-Biological evolution can be defined as the process of change in the population or species of organisms over time. One of the theories of evolution is natural selection which states that change in organism is brought over time as a result of changes in the heritable physical traits. The variation in gene frequencies comes up by genetic drift.
-Genetic drift is an evolutionary switch in allelic frequencies in a population. It takes place in tiny populations but the outcome is strong. It takes place because of the error in choosing the alleles for the upcoming generation from the gene pool of the ongoing generation. It does not take place due to environmental factors.
-In large populations allele frequency of the genes remain stable because the genes are not affecting fitness and do not have a natural selection pressure against the alleles.
-It is found that genetic drift is caused in smaller populations. In a tiny population with several alleles any of them can be lost. In a population with any organisms, there is less chance of losing an entire allele as many organisms have alleles and all the alleles cannot rub off.
-The effect of changes caused due to the change in gene frequencies is dependent on sample size. In smaller populations, changes in gene frequencies leads to visible effects on the survival of the organisms whereas in larger samples the survival of organisms may not be affected. It is because the affected allele may not vary the fitness of the organism and thus natural selection does not play a role in it. Example- In a large sample size, if an allele a in a species X is lost, the survival of many organisms need to be affected to understand the effect of allele a on species X.
-If an allele makes change to the organism like it leads to more reproduction of DNA, then frequency of allele becomes high. If the allele is hurt because of the organism, the allele frequency becomes low. When an allele frequency increases or decreases because of its presence in some random organism that survived it is known as genetic drift.
-Example: A group of rabbits with brown fur and white fur, white fur being the dominant allele. Because of genetic drift, only the brown population carry on with all the white ones removed.

Note: Allele frequencies change due to genetic drift. The population size plays a crucial role in controlling the allele frequencies. Genetic drift plays a crucial role in the evolution and development of a new population of species.