Show how selection, genetic drift, gene flow, and mutation relate to genetic variation. Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

(1) Gene flow genetic variation of a population
(2) Mutation genetic variation
(3) Selection genetic variation
(4) Genetic drift genetic variation

(A) Increases
(B) May increase, decrease or maintain
(C) Decreases
(D) May increase or decrease

Gene mutations are considered the primary sources of variability as they increase the number of alleles available on a locus by nucleotide addition, subtraction or substitution.

Natural selection tends to decrease genetic variability because only a few genotypes will be selected.

Gene flow is an evolutionary mechanism that results in the exchange of genetic information between individuals, populations, or species. Migrated genes can be advantageous, disadvantageous, or neutral.

Genetic drift is a mechanism of evolution where the frequencies of alleles in a population change over generations due to chance. Unlike natural selection, drift does not consider the benefit or impairment of an allele for an individual.