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Presents a study that determined the effect of laboratory and natural selection on the 70-Kd heat-shock protein (hsp70) genes of Drosophila melanogaster. Analysis of hsp70 allele frequencies in two sets of populations; Information on the studied populations and DNA extraction; Hsp70 polymorphism in the Australian and Cavichi populations.

To determine how the modern copy number (5) of hsp70 genes in Drosophila melanogaster evolved, we localized the duplication events that created the genes in the phylogeny of the melanogaster group, examined D. melanogaster genomic sequence to investigate the mechanisms of duplication, and analyzed the hsp70 gene sequences of Drosophila orena and Drosophila mauritiana. The initial two-to-four hsp70 duplication occurred 10–15 MYA, according to fixed in situ hybridization to polytene chromosomes, before the origin and divergence of the melanogaster and five other species subgroups of the melanogaster group. Analysis of more than 30 kb of flanking sequence surrounding the hsp70 gene clusters suggested that this duplication was likely a retrotransposition. For the melanogaster subgroup, Southern hybridization and an hsp70 restriction map confirmed the conserved number (4) and arrangement of hsp70 genes in the seven species other than D. melanogaster. Drosophila melanogaster is unique; tandem duplication and gene conversion at the derived cluster yielded a fifth hsp70 gene. The four D. orena hsp70 genes are highly similar and concertedly evolving. In contrast, the D. mauritiana hsp70 genes are divergent, and many alleles are nonfunctional. The proliferation, concerted evolution, and maintenance of functionality in the D. melanogaster hsp70 genes is consistent with the action of natural selection in this species. [ABSTRACT FROM PUBLISHER]

Presents a study which examined the effects of evolutionary history on the expression of heat shock protein (Hsp) 70 in Drosophila melanogaster. Materials and methods of the study; Evolutionary and acclimatory change in Hsp70 expression; Molecular bases of variation in Hsp70 expression.

Discusses the physiological relationship between heat shock protein (Hsp) 70 concentration and thermotolerance with focus on Drosophila species. Physiological changes of the Drosophila species at high temperature; Details on the manipulation of Hsp70; Information on protein expression in natural populations; Evidence from variation among Drosophila populations and species; Phylogenetic diversity in Hsp70.