Hendrix Roger W
Pittsburgh Bacteriophage Institute & Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260, USA.
Theor Popul Biol. 2002 Jun;61(4):471-80. doi: 10.1006/tpbi.2002.1590.
The dsDNA-tailed bacteriophages are probably the largest evolving group in the Biosphere and they are arguably very ancient. Comparative examination of genomes indicates that the hallmark of phage evolution is horizontal exchange of sequences. This is accomplished, first, by rampant non-homologous recombination between different genomes and, second, by reassortment of the variant sequences so created through homologous recombination. The comparative analysis suggests mechanisms by which new genes can be added to phage genomes and by which genes with novel functions may be assembled from parts. Horizontal exchange of sequences occurs most frequently among closely related phages, but it also extends across the entire global population at lower frequency. Bacteriophages also have probable ancestral connections with viruses of eukaryotes and archaea.
具有双链DNA尾的噬菌体可能是生物圈中进化规模最大的群体，而且可以说它们非常古老。基因组的比较研究表明，噬菌体进化的标志是序列的水平交换。这首先是通过不同基因组之间大量的非同源重组来实现的，其次是通过同源重组对由此产生的变异序列进行重配。比较分析揭示了新基因可以添加到噬菌体基因组的机制，以及具有新功能的基因可以由各部分组装而成的机制。序列的水平交换在亲缘关系密切的噬菌体之间最为频繁，但也以较低频率在全球整个噬菌体群体中发生。噬菌体与真核生物病毒和古生菌病毒也可能存在祖先联系。
