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.
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Received: 24 February 1997 / Accepted: 10 November 1997
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Kliman, R., Eyre-Walker, A. Patterns of Base Composition Within the Genes of Drosophila melanogaster . J Mol Evol 46, 534–541 (1998). https://doi.org/10.1007/PL00006334
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DOI: https://doi.org/10.1007/PL00006334