In a paper published online in advance in Nature this week, a team led by investigators at the Washington University School of Medicine presents an evaluation of how gut microbiomes differ among human populations. Based on its characterization of bacterial species in fecal samples from 531 individuals — from the Amazonas of Venezuela, rural Malawi, and US metropolitan areas — as well as the gene content of 110 of those individuals, the team identified "shared features of the functional maturation of the gut microbiome ... during the first three years of life in all three populations, including age-associated changes in the genes involved in vitamin biosynthesis and metabolism." Further, they note "pronounced differences in bacterial assemblages and functional gene repertoires" between residents of the US residents and residents of the other countries.
A team led by investigators at the Broad Institute reports having sequenced the genomes of 25 metastatic melanomas and matched germline DNA, through which it identified a "wide range of point mutation rates," and PREX2 as a significantly mutated gene in melanomas.
Over in Nature Genetics, researchers at the US National Cancer Institute and their colleagues discuss "detectable clonal mosaicism and its relationship to aging and cancer." In a meta-analysis involving data from 13 genome-wide association studies, the team unearthed mosaic abnormalities that were more frequent in individuals with solid tumors. Overall, the NCI-led group says its findings "underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases."
In a separate but related paper in the same jounal, a team led by investigators at the University of Washington also reports having identified "clonal mosaicism for large chromosomal anomalies using SNP microarray data from over 50,000 subjects recruited for genome-wide association studies," and discusses the implications of such "from birth to old age, and [their] relationship to cancer."