In PLOS Genetics, researchers from the Michigan State University and Harvard Medical School explore the consequences of sexual recombination during the process of bacterial evolution by Escherichia coli. Starting with a dozen evolving E. coli populations, the team repeatedly introduced another high-frequency recombination strain of E. coli into the mix as the original strain evolved over 1,000 generations, followed by 200 generations without recombination. When the genomes of E. coli from the successive generations were compared with one another, the authors found that frequent recombination did not necessarily enhance adaptation, noting that "genes that were physically linked to the genes causing recombination had a strong transmission advantage, whether or not they provided any selective advantage to the recipient cells."
An Arizona State University-led team takes a look at genomic features in Mycobacterium leprae representatives from naturally infected non-human primates for a paper appearing in PLOS Neglected Tropical Diseases. The researchers did genome sequencing on M. leprae isolates from a chimpanzee in Sierra Leone, a West African sooty mangabey, and a macaque in the Phillipines, using the sequences to assess phylogenetic relationships between the non-human primate strains and those causing leprosy in humans. While the macaque strain had genetic ties to a human M. leprae strain from New Caledonia, for example, they found that the chimp and sooty mangabey strains fell in a West African lineage of human M. leprae. "While the prevalence of natural leprosy in non-human primates is likely low," the authors write, "nevertheless, future studies should continue to explore the prevalence of leprosy-causing pathogens in the wild."
Finally, researchers from the University of Copenhagen, the University of Southern Denmark, and elsewhere search for new SNPs with ties to psoriasis, a chronic inflammatory condition. The team took a candidate gene approach to look for variants associated with psoriasis in more than 900 individuals with isolated cutaneous psoriasis or psoriatic arthritis compared with 795 unaffected controls, focusing on 53 SNPs in 37 known inflammation-related genes. The analysis led to two SNPs in the IL12B and TNF genes that were linked to moderate to severe psoriasis risk in psoriasis-affected individuals in Denmark, along with several more variants with nominal ties to one or both forms of the condition.