Allozyme variation in natural populations of Drosophila subobscura along a North-South gradient

✍ Scribed by W. Pinsker; D. Sperlich

• Publisher: Springer Netherlands
• Year: 1979
• Tongue: English
• Weight: 881 KB
• Volume: 50
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00122046

✦ Synopsis

Seven populations of Drosophila subobscura along a North-South gradient from Sweden to North Africa have been studied with respect to allozyme polymorphism at 17 loci. Drosophila subobscura shows no peculiarities with respect to the degree of the allozyme polymorphism for which average heterozygosity is 13.7 per cent. For only four of the thirteen polymorphic loci was no allele frequency variation between populations found. Another group of six loci showed significant frequency differences between populations. The changes, however, were not correlated with latitude. Finally three loci (Lap-4, Mdh-2 and 6-Pgdh) exhibited clinal changes in allele frequencies. A comparison of the allozyme polymorphism of D. subobscura with its inversion polymorphism revealed some correlations between frequency changes in inversions and those of alleles at enzyme loci on the same chromosome. The origin and maintenance of the observed allozyme-inversion associations is discussed and a model proposed which explains the recent frequency pattern of the association along the North-South gradient. Applying Nei's D value for aUozyme and inversion data the genetic distances between those populations separated by the Alps and those separated by the Mediterranean proved to be higher than those between the other populations. This might be understood as an indication that gene flow restriction has increased genetic divergence between these populations.