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Positive correlations between genomic % AT and genome size within strains of bacterial species
Author(s) -
Bohlin Jon,
Sekse Camilla,
Skjerve Eystein,
Brynildsrud Ola
Publication year - 2014
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12145
Subject(s) - genome , genome size , biology , gc content , phylogenetic tree , bacterial genome size , genetics , genome evolution , evolutionary biology , gene
Summary Genomic % AT has been found to correlate negatively with genome size in microbes. While microbes with large genomes are often GC rich and free living, AT ‐rich bacteria tend to be host associated with smaller genomes. With over 2000 fully sequenced and assembled microbial genomes available, we explored the relationship among genomic % AT , genome size, relative entropy (a measure associated with genetic drift) and fraction of genome islands ( GI s) in microbial species with the genomes of more than 10 strains available. A negative correlation with genome size was found in six out of 12 phylogenetic groups and subphyla and a positive correlation in only two. At the species level, we found a trend of positive correlations between genomic % AT and genome size in eight out of 20 species, while only four showed a negative correlation. Estimated chromosomal fractions of GI s were found to correlate positively with genome size in the strains of 14 out of 18 species and genomic % AT in the strains of seven species (two correlated negatively). Although GI s explain most of the observed positive correlations between genomic % AT and size, C hlamydia trachomatis seem to be an exception; therefore, these findings needs to be further explored.