Question

Explain how natural selection, genetic drift, mutations, and/or gene flow all lead to human genetic variation, using the examples from lab discussion.

Answer 1

First, we need to understand what is human genetic variation. This term refers to the different variants of a given gene that can be present in a specific population.

Natural selection

Natural selection is one of the basic mechanisms of evolution. Natural selection refers to the survival and reproduction of a particular species due to specific characteristics of their phenotype. For example, consider some bugs that have the ability to camouflage. These insects will have less chance to be eaten by a predator. In this example, the genes that confer the characteristic of camouflage will be passed from one generation to the next. In the other hand, the species that do not have the camouflage gene will not reproduce and survive as efficient as the bugs with he camouflage genes. Overall, Natural Selection helps human genetic variation by increasing the survival of human with specific genetic traits.

Genetic Drift

Genetic drift refers to the change in the proportion of genetic variants (alleles) due to the random nature of reproduction. This means that genetic drift can cause the loss of rares alleles and, can decrease the size of the gene pool. The effect of the Genetic Drift can make a population genetically different from its original population contributing to the human genetic variation.

Mutations

Mutations are changes in the nucleotidic sequence of the DNA. Sometimes this mutation can provide an evolutive advantage. An example of this is the mutation that gave the ability to the humans to digest lactate (carbohydrate present in the milk). It is important to mention that mutation are random events, therefore, mutations are not present in all the human beigns. The presence of mutations in specific human populations contributes to the genetic human variation as there will be individual with different mutations.