Abstract Volume 11 Issue 4 (1998), pp 439-452

Tracing the colonization of Madeira and the Canary Islands by Drosophila subobscura through the study of the rp49 gene region

¹Departamento da Biologia, Universidade da Madeira, Funchal, Portugal
²Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, E-08071 Barcelona, Spain,

Received: 20 December 1996; accepted 25 April 1997.

Abstract. Nucleotide variation at the nuclear ribosomal protein 49 (rp49) gene region has been analysed by fine restriction mapping in a sample of 47 lines from a population from Madeira. Five restriction-site (out of 37 sites scored) and 3 length polymorphisms have been detected, resulting in 14 different haplotypes. This population shows less variation than both continental and Canary Island populations. The population from Madeira shows some differentiation from mainland populations, which does not favor the idea of extensive migration between the continent and Madeira. Chromosomal and restriction-map variation of the rp49 region in D. subobscura populations, together with data on sequence comparison of this nuclear region in D. guanche and D. madeirensis clearly indicate that the Canary Islands underwent at least two colonization events from the nearby continent. Although the data for Madeira are compatible with a single colonization event by a continental sample polymorphic for gene arrangements O₃ and O₃₊₄, an alternative scenario with at least two colonization events seems more likely.

Key words. Drosophila subobscura species cluster; rp49 gene region; colonization; Canary Islands; Madeira.

Article in PDF-format (187 kB)