Unusual arrangement of the hsp68 locus in the virilis species group of Drosophila implicates evolutionary loss of an hsp68 gene.
Unlike all other Drosophila species studied to date, species in the virilis group of Drosophila have 2 complete copies of hsp68 arranged in inverted head-to-head orientation. Evidence for this conclusion includes Southern blots for D. virilis, D. lummei, and D. montana, PCR analysis of the former 2 species, in situ hybridization in D. virilis x D. lummei hybrids, and the complete nucleotide sequence of the locus in D. lummei. This organization resembles the primitive state of hsp70 in Diptera. Moreover, the Hsp68 peptide sequence for D. virilis and D. lummei is intermediate between that of Hsp70 and Hsp68 from other Drosophila spp. Therefore, we suggest that the hsp68 locus may have arisen via duplication of the hsp70 locus (or vice versa) early in the history of the genus Drosophila, with 1 hsp68 copy subsequently lost in most other Drosophila species groups.
Velikodvorskaia
Vera V
VV
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
Lyozin
Georgii T
GT
Feder
Martin E
ME
Evgen'ev
Michael B
MB
D000595:Amino Acid Sequence; D000818:Animals; D004330:Drosophila / Q000145:classification / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics*; D019143:Evolution, Molecular; D017353:Gene Deletion; D018628:Gene Dosage; D020440:Gene Duplication; D014644:Genetic Variation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010802:Phylogeny
D029721:Drosophila Proteins; D018840:HSP70 Heat-Shock Proteins; C490785:Hsp68 protein, Drosophila