Characterization of the boundaries between adjacent rapidly and slowly evolving genomic regions in Drosophila.

Abstract

The site of a dramatic change in the rate of DNA sequence evolution exists near the 68C glue gene clusters of several Drosophila species. We have previously determined the approximate location of this transition site by comparison of restriction maps of the regions flanking the 68C-like glue gene cluster of five members of the melanogaster species subgroup. In the present work we report the sequence of the transition region in three of these Drosophila species: D. melanogaster, D. yakuba, and D. erecta. Using a best-fit alignment of these sequences, we rind that the site of transition from slowly to rapidly evolving sequences occurs abruptly within a region <50 nucleotides in length. Sequencing. DNA sequencing was performed by the dideoxy chain-termination method of Sanger et al. (12). Custom oligonucleotides, used to prime sequencing reactions from sites in the interior of a cloned insert, were provided by S. Horvath of the California Institute of Technology Microchemical Facility. These primers were purified and used as described in Strauss et al. (13). All sequences were determined on both strands.Computer Analysis. DNA sequences were analyzed using programs written by one of the authors (C.H.M.) for an IBM PC-XT computer. DNA sequences were aligned using the algorithm of Gotoh (14) as implemented by R. Pruitt on an Apple Macintosh computer. RESULTSThe border between regions of high and low conservation was located by inspection of the restriction maps of regions containing and adjacent to the cloned glue gene clusters. The broken vertical line in Fig. 1 The sequencing strategy is diagrammed in Fig. 2. All sequences start at the EcoRI site (R) that lies at least 1000 Abbreviation: kb, kilobase pair(s). 8654The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Localized hypermutation and associated gene losses in legume chloroplast genomes

“…One early study (Martin and Meyerowitz 1986) reported a 2-kb region of noncoding DNA near the glue gene cluster of three Drosophila species, which contained an abrupt boundary between a conserved region and a nonconserved region with a 10-fold elevated substitution rate, but this report has not been followed up with more extensive analyses based on complete genome sequence data. An abrupt boundary of evolutionary rates also occurs on the mammalian X chromosome at the junction between the pseudoautosomal region and the X-specific region.…”

Taxonomic identification of Drosophila nasuta subgroup strains by glue protein analysis

“…In the case of glue proteins, however, it is hard to believe that the survival of the flies is dependent on a specific composition of glue, because completely different patterns have been reported in wildtype strains of D. melanogaster (Beckendorf & Kafatos, 1976;Korge, 1977;Velissariou & Ashburner, 1980), in D. hydei (Ramesh & Kalisch, unpublished), and in others (Manousis, 1985). In this connection, one also has to consider the possibility that the genome posesses the ability to regulate differentially the rate of evolution of DNA sequences in different chromosomal locations (Martin & Meyerowitz, 1986).…”

Molecular analysis of the intergenic region of the duplicated amy genes of drosophila melanogaster and drosophila teissieri

“…Therefore we think that these subregions are functionally important in evolution--for example, for Amy genes or for other genes. Alternatively, these region may just have lower mutation rates, as suggested in other regions of Drosophila genome (Martin and Myerowitz 1986;Werman et al 1990). Further analyses mutagenizing these subregions or finding strains having structural changes in these regions may resolve this issue.…”