The bacteria that cause a tropical disease called yaws can recombine with the related bug behind sexually transmitted or congenital syphilis infections via horizontal gene transfer, according to a study in PLOS Neglected Tropical Diseases. Researchers from the Czech Republic and the US sequenced the roughly 1.1 million base genome of a syphilis-causing Trepona pallidum sub-species pallidum strain from Mexico. When they compared this sequence with three more T. pallidum pallidum strains and three strains of T. pallidum pertenue, the sub-species that causes yaws, investigators saw signs of recombination in the newly sequenced Mexican syphilis strain. In particular, two genes in this strain seemed to be a mash up of versions normally found in syphilis- and yaws-causing bacteria, the team reports, apparently produced through sequence swapping in an individual infected with both bugs.
Based on their population analyses, researchers from Johns Hopkins University, Wake Forest University, and elsewhere argue that mutations to a cluster of fatty acid desaturase genes may have helped spur early human migrations throughout Africa. As they write in PLOS One, the investigators looked at sequences in and around the FADS gene cluster in 1,092 1000 Genomes Project participants from more than a dozen populations. Combined with data for more than 1,000 individuals genotyped for the Human Genome Diversity Panel, a search for signs of selection in the FADS region led the team to FADS alleles that appear to have become nearly fixed in ancestral African populations around 85,000 years ago. That, they say, produced versions of these enzymes that are more efficient at converting medium chain polyunsaturated fatty acids — such as those found in plants — to long chain polyunsaturated fatty acids. Study authors argue that such adaptations would theoretically have freed humans from their dependence on seafood-based sources of these fatty acids, which are used to support complex human brain structures and functions.
In PLOS Genetics, members of the "Genetics of Nephrology: an International Effort," or GENIE consortium describe loci linked to kidney disease in individuals with type 1 diabetes. In an effort to understand the genetic basis for diabetic kidney disease, a diabetic complication that can lead to end-stage renal disease, the researchers did a meta-analysis using data for nearly 6,700 individuals that had been generated through past genome-wide association studies. From this analysis, combined with follow-up testing of suspicious SNPs, the group narrowed in on a potential association between diabetic kidney disease (also called diabetic nephropathy) and a SNP falling in the intron of an epidermal growth factor receptor gene called ERBB4. Two more variants had significant ties to end-stage renal disease risk in individuals with type 1 diabetes. One of these fell in the chromosome 2 gene AFF3, while the other turned up between two genes on chromosome 15.