NEW YORK (GenomeWeb News) – A Nature Genetics study suggests variants at two genetic loci make some individuals more prone to complications of dengue fever, an infectious disease caused by mosquito-transmitted viruses. An international group did a genome-wide association study involving thousands of individuals in Vietnam who had been treated for hypovolemic shock (also known as dengue shock syndrome), a serious dengue fever complication in which blood seeps out of blood vessels. Following a GWAS involving more than 2,000 children treated for dengue shock syndrome and about as many healthy controls, along with a replication study of 1,737 more cases and 2,934 controls, the researchers found one genome-wide significant risk locus in the MICB gene on chromosome 6 and another in the chromosome 10 gene PLCE1.
"Our study confirms epidemiological evidence that some people are naturally more susceptible to severe forms of the disease than others," co-senior author Cameron Simmons, a researcher with Oxford University's Clinical Research Unit in Vietnam, said in a statement. "Our findings offer tantalizing clues as to why this should be the case and open up new avenues for us to explore to help us understand the disease."
In a study scheduled to appear online in the Proceedings of the National Academy of Sciences, researchers from the University at Albany, State University of New York and the Roswell Park Cancer Institute used the budding yeast Saccharomyces cerevisiae as a model system to look at how a type of mobile genetic elements called endogenous Ty1 retrotransposons contribute to genome instability during aging. The team found that Ty1 retrotransposons became more mobile in the genomes of yeast from older populations, which, in turn, ups the risk of chromosomal rearrangements and instability in the yeast genomes. On the other hand, researchers reported, conditions that curb retrotransposon activity seem to rein in age-associated chromosome loss and loss of heterozygosity events.
"Retrotransposition may contribute to genetic damage during aging in diverse organisms and provide a useful tool for studying whether genetic damage is a causative factor for aging," senior author M. Joan Curcio, a biology researcher at the University at Albany, and co-authors wrote.
The evolution of gene expression patterns vary between animal lineages and from one tissue type to the next, a Swiss-led team has found. The researchers used the Illumina GAIIx to sequence polyadenylated RNA from 10 placental mammal, marsupial, monotreme, or bird species, chronicling the transcriptome patterns in six organs per species. As they report in Nature, the team found evidence that gene expression is subject to variable evolution patterns depending on the chromosome, organ, and animal lineage involved.
"Although gene expression evolution in mammals was strongly shaped by purifying selection," senior author Henrik Kaessmann, a University of Lausanne researcher, and co-authors wrote, "we identify numerous potentially selectively driven expression switches, which occurred at different rates across lineages and tissues and which probably contributed to the specific organ biology of various mammals."
The first mastodon hunting in North America occurred some 14,000 years ago, nearly 1,000 years earlier than previously estimated, according to a study by investigators from Denmark and the US. As they report in Science, the team used a combination of protein sequence analyses, mitochondrial DNA sequencing, imaging, and radiocarbon dating to test a spearhead-shaped piece of bone found embedded in the remains of a mastodon excavated in Washington state. Their analyses suggest that the spearhead itself was made from the bone of a mastodon killed earlier, suggesting human hunting began back well before the arrival of people belonging to a group known as the Clovis culture around 13,000 years ago.
"[I]t was not a sudden war or a quick slaughtering of the mastodons by the Clovis culture, which made the species disappear," senior author Eske Willerslev, a researcher at the University of Copenhagen's Centre for GeoGenetics, said in a statement. "We can now conclude that the hunt for the animals stretched out over a much longer period of time."
Genomics In The Journals is a weekly feature pointing readers to select, recently published articles involving genomics and related research.