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This Week in PNAS: Nov 4, 2009

In a paper published this week in PNAS, University of Edinburgh scientists show that "the majority of S. aureus isolates from broiler chickens are the descendants of a single human-to-poultry host jump," which they believe happened about 38 years ago, by a subtype of a lineage from Poland. This ST5 clade has adapted to its new host through acquiring new mobile elements and inactivating several important human disease genes, they say.

While the conserved Stn1 and Ten1 proteins are required for proper capping of the telomere, says the abstract of a paper authored in part by Deborah Wuttke at the University of Colorado, Boulder, "the mechanistic details of how they contribute to telomere maintenance are unclear." In the paper, scientists have solved the crystal structures of the C-terminal domain of the Saccharomyces cerevisiae Stn1 and the Schizosaccharomyces pombe Ten1 proteins. They found that the structures are similar to replication protein A complex with an evolved telomere-specific domain, "further supporting an evolutionary link between telomere maintenance proteins and DNA repair complexes."

Michael Hart at Simon Fraser University and Richard Grosberg at the University of California, Davis, have disproved a theory that caterpillars evolved from velvet worms by hybridogenesis. Comparing the genomes of velvet worms and insects both with and without larvae, they found that ancestors of velvet worms did not give rise to insect caterpillars through hybridization, or "larval transfer."

Scientists at Rinat-Pfizer in South San Francisco have used a combination of sys bio tools to characterize the diversity of human antibodies, otherwise known as immunoglobulins. Using phage display, massively parallel pyrosequencing, "a novel application of Kabat column-labeled profile Hidden Markov Models, and translated complementarity determining region (CDR) capture-recapture analysis," they found many different germline contributions with random heavy and light chain pairing and that the total diversity from a human IgM pool was at least 3.5 × 1010.

The Scan

Fertility Fraud Found

Consumer genetic testing has uncovered cases of fertility fraud that are leading to lawsuits, according to USA Today.

Ties Between Vigorous Exercise, ALS in Genetically At-Risk People

Regular strenuous exercise could contribute to motor neuron disease development among those already at genetic risk, Sky News reports.

Test Warning

The Guardian writes that the US regulators have warned against using a rapid COVID-19 test that is a key part of mass testing in the UK.

Science Papers Examine Feedback Mechanism Affecting Xist, Continuous Health Monitoring for Precision Medicine

In Science this week: analysis of cis confinement of the X-inactive specific transcript, and more.