Habitat selection maintains a deleterious allele in a heterogeneous environment

• Published in: Nature (London) 1980-01, Vol.287 (5783), p.632-633
• Main Authors: Jones, J. S., Probert, R. F.
• Format: Article
• Language: English
• Subjects: Humanities and Social Sciences; letter; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/287632a0

Little is known of how the large amount of genetic variation found in natural populations is maintained. Diversifying natural selection in a heterogeneous environment has great potential for promoting genetic polymorphism 1 . If one allele is favoured in one microhabitat and the alternative allele in another (which may be separated from the first by space or time), the disruptive effects of selection can maintain both alleles in the population. The limiting conditions of niche size, selective intensity and gene flow which could in theory maintain polymorphism in this way have been widely discussed 2,3 . This mechanism is much more effective in promoting genetic diversity if carriers of the alternative alleles are able to select the niche in which their fitness is greatest 4 . Here we explore the properties of a system in which two Drosophila eye colour alleles, known to show differences in fitness, are given the opportunity to select different microhabitats in a population cage. It seems that habitat selection in a heterogeneous environment can lead to the maintenance of polymorphism for an allele which is disadvantageous in either habitat when no opportunity for choice is available.