The colonization of drosophila subobscura in Chile. II. Clines in the chromosomal arrangements

Drosophila subobscura is a Palearctic species that was first detected in the New World in Puerto Montt (Chile) in February 1978. Since that time, it has spread over a broad area and increased in population density. The South American populations exhibit a high level of chromosomal polymorphism: 20 d...

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Bibliographic Details
Published in:Evolution 1985-07, Vol.39 (4), p.838-844
Main Authors: Prevosti, A, Serra, L, Ribo, G, Aguade, M, Sagarra, E, Monclus, M, Garcia, M.P
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
CHILE
CHILI
CHROMOSOME POLYMORPHISM
Chromosomes
Clines
Correlations
DROSOPHILA
Drosophila subobscura
Drosophilidae
Evolutionary genetics
Fundamental and applied biological sciences. Psychology
Genetics of eukaryotes. Biological and molecular evolution
Human genetics
Natural selection
Population genetics
Population genetics, reproduction patterns
Species
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Summary:Drosophila subobscura is a Palearctic species that was first detected in the New World in Puerto Montt (Chile) in February 1978. Since that time, it has spread over a broad area and increased in population density. The South American populations exhibit a high level of chromosomal polymorphism: 20 different arrangements exist, distributed among five chromosomes. Chromosomal arrangement heterozygosity varies from 0.55 to 0.61 in the nine populations examined. Incipient clines in the frequencies of the arrangements are appearing; these clines follow the same latitudinal direction as in the Old World. Wing length significantly decreases with latitude, as it does in Europe. The colonization of South America by D. subobscura appears to be a major natural experiment with outcomes that duplicate the distributional patterns-in chromosomal polymorphism and in wing length-observed in the Old World, thereby strongly supporting the adaptive significance of these patterns. The data show a very rapid effect of natural selection promoting genetic differentiation among natural populations.
ISSN:0014-3820
1558-5646
DOI:10.1111/j.1558-5646.1985.tb00425.x