Investigating the relationship between genome structure, composition, and ecology in prokaryotes.
Investigating the relationship between genome structure, composition, and ecology in prokaryotes.
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研究原核生物基因组结构、组成和生态之间的关系。
DOI：
10.1093/oxfordjournals.molbev.a004136
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发表时间：
2002
影响因子：
10.7
通讯作者：
Liò,Pietro
中科院分区：
文献类型：
--
作者：
Liò,Pietro
Our thesis is that the DNA composition and structure of genomes are selected in part by mutation bias (GC pressure) and in part by ecology. To illustrate this point, we compare and contrast the oligonucleotide composition and the mosaic structure in 36 complete genomes and in 27 long genomic sequences from archaea and eubacteria. We report the following findings (1) High–GC-content genomes show a large underrepresentation of short distances between Gnand Cnhomopolymers with respect to distances between Anand Tnhomopolymers; we discuss selection versus mutation bias hypotheses. (2) The oligonucleotide compositions of the genomes ofNeisseria(meningitidisandgonorrhoea),Helicobacter pyloriandRhodobacter capsulatusare more biased than the other sequenced genomes. (3) The genomes of free-living species or nonchronic pathogens show more mosaic-like structure than genomes of chronic pathogens or intracellular symbionts. (4) Genome mosaicity of intracellular parasites has a maximum corresponding to the average gene length; in the genomes of free-living and nonchronic pathogens the maximum occurs at larger length scales. This suggests that free-living species can incorporate large pieces of DNA from the environment, whereas for intracellular parasites there are recombination events between homologous genes. We discuss the consequences in terms of evolution of genome size. (5) Intracellular symbionts and obligate pathogens show small, but not zero, amount of chromosome mosaicity, suggesting that recombination events occur in these species.
