In PLOS Genetics, researchers from Iceland and Denmark consider the consequences of multi-nucleotide de novo mutations in the human genome. Based on whole-genome sequences for individuals from 283 parent-offspring trios sequenced in Iceland, the team tracked down nearly 18,000 single nucleotide changes and just shy of 1,300 small insertions and deletions. From there, the investigators estimated single nucleotide variant and multi-nucleotide mutation rates per generation, leading them to suggest that some 3 percent of de novo single nucleotide variants fall within multi-nucleotide mutations.
A team from Loyola University Chicago describes findings from a genome sequencing study of Gardnerella bacterial strains isolated from bladder microbial communities of women with urinary incontinence. As they report in PLOS One, the researchers sequenced four Gardnerella isolates by pooled, barcoded Illumina MiSeq sequencing, using the assembled genomes and comparisons with available sequences from other microbes isolated from the bladder and/or vagina to identify strain-specific genes, lineage-specific genes, and sequences that appeared to stem from prophage viruses in the bacteria. Along with an extensive pangenome in the bladder Gardnerella isolates, for example, the authors argue that "[t]he abundance of prophage sequences within the strains … suggests that phages could play an important role in the species' evolutionary history and in its interactions within the complex communities found in the female urinary and reproductive tracts."
Researchers from China explore information that might be gleaned from circulating microRNAs in individuals with atrial fibrillation for another PLOS One paper. The team did array-based miRNA expression profiling on peripheral blood samples from 90 individuals with atrial fibrillation and as many unaffected individuals, along with miRNA profiling on coronary sinus blood samples from those with atrial fibrillation. From miRNAs that appeared to differ in their coronary sinus blood and peripheral blood expression in individuals with atrial fibrillation, the investigators narrowed in on six miRNAs with significantly higher expression in the coronary sinus blood and eight with significant down-regulation. In the peripheral blood samples, meanwhile, 16 miRNAs had higher expression in patients versus controls, while two dozen miRNAs had diminished expression.