Mutation pressure, natural selection, and the evolution of base composition in Drosophila
Mutation pressure, natural selection, and the evolution of base composition in Drosophila
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DOI：
10.1023/a:1017078607465
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发表时间：
1998-01-01
期刊：
影响因子：
1.5
通讯作者：
Eyre-Walker, A
中科院分区：
文献类型：
--
作者：
Akashi, H;Kliman, RM;Eyre-Walker, A
许多分类群的基因组测序揭示了基因组区域和DNA功能位点之间核苷酸组成的差异。突变偏差、有偏差的基因转换和自然选择被认为是这种变异的原因。在这里，我们回顾了果蝇DNA的碱基组成模式。黑腹果蝇的核苷酸组成存在区域性差异，碱基组成在内含子和外显子之间存在相关性。果蝇物种也显示出惊人的非随机密码子使用模式。同义密码子的使用模式和翻译的生物化学表明，自然选择可能在“沉默”的位点起作用。重组率与密码子使用之间的关系以及物种内部和物种之间沉默突变的进化动力学比较支持自然选择对同义密码子的区别。区域碱基组成变化的原因尚不清楚。非编码DNA的功能研究、基因组模式的进一步研究以及基于进化理论的统计测试的进展，将使人们更好地理解突变过程和自然选择在全基因组核苷酸组成模式中的作用。
Genome sequencing in a number of taxa has revealed variation in nucleotide composition both among regions of the genome and among functional classes of sites in DNA. Mutational biases, biased gene conversion, and natural selection have been proposed as causes of this variation. Here, we review patterns of base composition in Drosophila DNA. Nucleotide composition in Drosophila melanogaster varys regionally, and base composition is correlated between introns and exons. Drosophila species also show striking patterns of non-random codon usage. Patterns of synonymous codon usage and the biochemistry of translation suggest that natural selection may act at 'silent' sites. A relationship between recombination rates and codon usage and comparisons of the evolutionary dynamics of silent mutations within and between species support natural selection discriminating among synonymous codons. The causes of regional base composition variation are less clear. Progress in functional studies of non-coding DNA, further investigations of genome patterns, and statistical tests based on evolutionary theory will lead to a greater understanding of the contributions of mutational processes and natural selection in patterning genome-wide nucleotide composition.