Identification of genomic islands in the genomes of five Prochlorococcus strains by multiple genomic comparison
通过多基因组比较的方法在5种绿球蓝细菌中识别基因组岛

In order to explore the role of horizontal gene transfer in the divergence of genomes within the genus Prochlorococcus,the genomes of five high light-adapted strains of Prochlorococcuswere compared . Firstly,both bidirectional best BLASTP search and the conservation of gene order against each other were employed to predict orthologs;then the alien genes in one Prochlorococcusstrain were identified by examining how many orthologs its each gene had in the genomes of the four other strains . As for a genomic island,it refers to a region composed of one or more contiguous alien genes . The results showed that the number of genomic islands in the five genomes ranged from16 to52 .Many of the genes in these islands showed similarity to genes found in viral genomes or sequences derived from virus-enriched environmental samples . These results suggest that viruses may have mediated horizontal gene transfer,resulting in genomic divergence amongst Prochlorococcus genomes .