Tracking the origin of an invasive species: Drosophila subobscura in Argentina

FERNÁNDEZ IRIARTE P., J. BALANYA, M. PASCUAL, F. MESTRES, E. HASSON, A. FONTDEVILA & L. SERRA

JOURNAL OF EVOLUTIONARY BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2008 vol. 22 p. 650 - 658

1010-061X

Biological invasions are excellent opportunities to study the evolutionary forces leading to the adaptation of a species to a new habitat. Knowledge of the introduction history of colonizing species helps tracking colonizing routes and assists in defining management strategies for invasive species. The Palearctic species Drosophila subobscura is a good model organism for tracking colonizations since it was detected in Chile and western North America three decades ago and later on in the Atlantic coast of Argentina. To unravel the origin of the Argentinean colonizers two populations have been analyzed with several genetic markers. Chromosomal arrangements and microsatellite alleles found in Argentina are almost the same as those observed in Chile and USA. The lethal allelism test demonstrates that the lethal gene associated to the O5 inversions in Argentina is identical to that found in Chile and USA, strongly supporting the hypothesis that all the American colonizing populations originated from the same colonization event. A secondary bottleneck is detected in the Argentinean populations and the genetic markers suggest that these populations originated from the invasion of 80-150 founding individuals from Chile.