G Gene Pool Prerna Giri and Bhagyalaxmi Mohapatra Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, UP, India Synonyms Gene; Genotype; Heredity Definition The sum of all the genes in a given population at a given time can be referred to as gene pool. The term gene pool is used in reference to a population which includes all individuals of the same species and includes all genes and combinations of genes (sum of all the alleles) in the population. Introduction The concept of gene pool was given by Russian geneticist Aleksandr Sergeevich Serebrovskii in the 1920s as genofond (gene fund). The term “Genofond” was imported to the United States from the Soviet Union by Theodosius Dobzhansky, who translated it into English as “gene pool.” Gene pool refers to the collection of genes in an interbreeding population that includes each gene at a certain frequency in rela- tion to its alleles. The gene pool is a measure of generic diversity. The composition of a population’ s gene pool can change over time through evolution. This can occur by a variety of mechanisms such as mutations leading to genetic variation, natural selection, genetic drift, habitat diversity, and geographical isolation. Such pro- cesses can cause an altered gene pool which is attenuated to the needs of the population’ s specific environment. For example, the migration of human population from equatorial region towards north where they were exposed to lesser amount of sunlight, resulted in variations in skin color over due course of time. The genetic modifica- tions responsible for changes in the skin color become part of this population’ s gene pool. In contrast to this, several endemic species of tor- toise and marine iguanas of Galapagos Island and aye-aye species of lemur in Madagascar island are example of least diverged genepool. Changes in the Gene Pool Gene pool changes with time, it does not always stay the same. The changes in the gene pool of a population over time that result in changes to the varieties of individuals in a population is known as microevolution. Example of microevolution may include bacteria that have become insensitive to antibiotic over time. Small changes in the gene pool can happen for a number of reasons; a few of # Springer International Publishing AG 2018 J. Vonk, T. K. Shackelford (eds.), Encyclopedia of Animal Cognition and Behavior, https://doi.org/10.1007/978-3-319-47829-6_69-1