Evolutionary rearrangement of the amylase genomic regions between Drosophila melanogaster and Drosophila pseudoobscura

Two Drosophila pseudoobscura genomic clones have sequence similarity to the Drosophila melanogaster amylase region that maps to the 53CD region on the D. melanogaster cytogenetic map. The two clones with similarity to amylase map to sections 73A and 78C of the D. pseudoobscura third chromosome cytogenetic map. The complete sequences of both the 73A and 78C regions were compared to the D. melanogaster genome to determine if the coding region for amylase is present in both regions and to determine the evolutionary mechanism responsible for the observed distribution of the amylase gene or genes. The D. pseudoobscura 73A and 78C linkage groups are conserved with the D. melanogaster 41E and 53CD regions, respectively. The amylase gene, however, has not maintained its conserved linkage between the two species. These data indicate that amylase has moved via a transposition event in the D. melanogaster or D. pseudoobscura lineage. The predicted genes within the 73A and 78C regions show patterns of molecular evolution in synonymous and nonsynonymous sites that are consistent with previous studies of these two species.