title: Patterns of base composition within the genes of Drosophila melanogaster.
abstract: Base composition is not uniform across the genome of Drosophila melanogaster. Earlier analyses have suggested that there is variation in composition in D. melanogaster on both a large scale and a much smaller, within-gene, scale. Here we present analyses on 117 genes which have reliable intron/exon boundaries and no known alternative splicing. We detect significant heterogeneity in G+C content among intron segments from the same gene, as well as a significant positive correlation between the intron and the third codon position G+C content within genes. Both of these observations appear to be due, in part, to an overall decline in intron and third codon position G+C content along Drosophila genes with introns. However, there is also evidence of an increase in third codon position G+C content at the start of genes; this is particularly evident in genes without introns. This is consistent with selection acting against preferred codons at the start of genes.
authors.affiliation: Department of Biology, Radford University, Radford, VA 24142, USA. rklimanrunet.edu
authors.forename: R M
authors.initials: RM
authors.lastname: Kliman
authors.forename: A
authors.initials: A
authors.lastname: Eyre-Walker
mesh_terms: D000818:Animals; D001482:Base Composition; D004331:Drosophila melanogaster / Q000235:genetics*; D005091:Exons; D017344:Genes, Insect; D014644:Genetic Variation; D007438:Introns