Microbial communities living in the guts of some ancient humans most closely resemble those found in present-day rural populations, according to a PLOS One study. Researchers from the University of Oklahoma and elsewhere used 16S ribosomal RNA sequencing to assess microbial community members in ancient fecal samples from human remains at three archeological locales: a 1,400-year-old site in northern Mexico, a 1,600-year-old site in northern Chile, and an 8,000-year-old site in the southern US. Through comparisons with data on microbes from numerous natural and human-associated sites, the team determined that the gut microbe communities in feces from the northern Mexico site, called Rio Zape, were similar to the modern gut microbiomes of children from African populations with traditional rural lifestyles. So too, were gut microbiomes previously described for Ötzi — the Tyrolean Iceman — and an Austrian solider frozen nearly 100 years.
For more on this study, check out a related news story in GenomeWeb Daily News.
The National Institute of Environmental Health Sciences' Dmity Gordenin led an American team that reports this week on single-stranded DNA mutagens in PLOS Genetics. Using a yeast reporter system, the researchers profile the nature and extent of single-stranded DNA mutations associated with exposure to reactive sulfur oxides. Results of the analysis uncovered clusters of mutations in the single-stranded DNA following sulfite treatment, study authors report, particularly affecting cytosine nucleotides. More generally, they say, the methods used in the study "ascertained molecular mechanisms of action by which agents can mutate [single-stranded DNA] specifically within cells, an area that warrants much investigation following reports that [single-stranded DNA]-specific damage accounts for similar mutation clusters, and up to 40 percent of all mutations, in various cancers."
A team from Belgium and the US retraces the gene duplication-related molecular mechanisms at play during the evolution of a large family of fungal metabolic enzymes from a single ancestral enzyme. As they report in PLOS Biology, the researchers focused on genes within the glucosidase family, which code for enzymes that help fungi exploit various sugars. After determining the ancestral, pre-duplication state of the original fungal glucosidase gene based on genomic data for several existing yeast species, investigators were able to retrace the interconnected series of gene duplication and innovation-related events that produced the collection of glucosidase genes found in fungi today.