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This Week in PLOS: Sep 14, 2015

A PLOS Neglected Tropical Diseases paper by investigators in Colombia relied on human genetic clues when considering the origin of leprosy in that country. Using three-dozen ancestry informative markers, the team tested samples from 118 leprosy-infected individuals and 116 leprosy-free controls from Colombia's Atlantic and Andean regions. It also did genotyping on the Mycobacterium leprae isolates involved in these infections. Human populations in the Atlantic region tended to have higher proportions of African ancestry and were more frequently infected with an M. leprae haplotype traced back to Africa, the study's authors note, while Andean individuals, who had more pronounced European ancestry, were more often infected with a leprosy bug believed to originate in Europe. "These results suggest that the human and M. leprae genomes have co-existed since the African and European origins of the disease," they write, "with leprosy ultimately arriving in Colombia during colonization."

An international team led by investigators in Germany combined genomics with metabolomics to search for genetic variants influencing each individual's urinary metabolite profiles. As they report in PLOS Genetics, the researchers used both targeted and non-targeted proton NMR testing on urine samples from more than 5,500 individuals who had been genotyped with SNP arrays. Together, this data made it possible to track down 22 loci linked to urinary metabolite traits. Among them were 15 sites not detected in past studies as well as several sites that overlapped with loci that were previously associated with blood metabolite patterns.

In PLOS One, Malaysian researchers describe findings from a gene expression study of the fungal pathogen Cryptococcus neoformans, which can cause pulmonary and central nervous system infections, particularly in those with compromised immune function. Using array-based gene expression profiling, the team compared transcript patterns in four C. neoformans strains, including one clinical reference strain with relatively high virulence and three environmental strains known as H4, S48B, and S68B that were isolated from bird droppings. Results from the analysis revealed dozens of genes showing higher or lower expression in the clinical strain compared to its environmental counterparts, providing clues to C. neoformans pathogenesis.