Evolution of gene sequence in response to chromosomal location.
Evolutionary forces acting on the repetitive DNA of heterochromatin are not constrained by the same considerations that apply to protein-coding genes. Consequently, such sequences are subject to rapid evolutionary change. By examining the Troponin C gene family of Drosophila melanogaster, which has euchromatic and heterochromatic members, we find that protein-coding genes also evolve in response to their chromosomal location. The heterochromatic members of the family show a reduced CG content and increased variation in DNA sequence. We show that the CG reduction applies broadly to the protein-coding sequences of genes located at the heterochromatin:euchromatin interface, with a very strong correlation between CG content and the distance from centric heterochromatin. We also observe a similar trend in the transition from telomeric heterochromatin to euchromatin. We propose that the methylation of DNA is one of the forces driving this sequence evolution.
Díaz-Castillo
Carlos
C
Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA. diazcastillo@biology.utah.edu
Golic
Kent G
KG
D000818:Animals; D001482:Base Composition; D003062:Codon; D019175:DNA Methylation; D004331:Drosophila melanogaster / Q000145:classification / Q000235:genetics*; D022041:Euchromatin / Q000235:genetics; D019143:Evolution, Molecular; D006570:Heterochromatin / Q000235:genetics*; D008957:Models, Genetic; D005810:Multigene Family; D019209:Troponin C / Q000145:classification / Q000235:genetics*
D003062:Codon; D022041:Euchromatin; D006570:Heterochromatin; D019209:Troponin C