Phylogeny and prediction of genetic similarity of Cronobacter and related taxa by multilocus sequence analysis (MLSA)

Multilocus sequence analysis (MLSA) based on recN, rpoA and thdF genes was done on more than 30 species of the family Enterobacteriaceae with a focus on Cronobacter and the related genus Enterobacter. The sequences provide valuable data for phylogenetic, taxonomic and diagnostic purposes. Phylogenetic analysis showed that the genus Cronobacter forms a homogenous cluster related to recently described species of Enterobacter, but distant to other species of this genus. Combining sequence information on all three genes is highly representative for the species' %GC-content used as taxonomic marker. Sequence similarity of the three genes and even of recN alone can be used to extrapolate genetic similarities between species of Enterobacteriaceae. Finally, the rpoA gene sequence, which is the easiest one to determine, provides a powerful diagnostic tool to identify and differentiate species of this family. The comparative analysis gives important insights into the phylogeny and genetic relatedness of the family Enterobacteriaceae and will serve as a basis for further studies and clarifications on the taxonomy of this large and heterogeneous family.

Genome sequence, comparative analysis, and population genetics of the domestic horse

We report a high-quality draft sequence of the genome of the horse (Equus caballus). The genome is relatively repetitive but has little segmental duplication. Chromosomes appear to have undergone few historical rearrangements: 53% of equine chromosomes show conserved synteny to a single human chromosome. Equine chromosome 11 is shown to have an evolutionary new centromere devoid of centromeric satellite DNA, suggesting that centromeric function may arise before satellite repeat accumulation. Linkage disequilibrium, showing the influences of early domestication of large herds of female horses, is intermediate in length between dog and human, and there is long-range haplotype sharing among breeds.