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This Week in Science: May 29, 2009

The big news in Science this week is that Human Microbiome Project researchers sequenced 16S ribosomal RNA genes at 20 distinct skin sites from healthy humans and found bacteria from 18 different phyla. The most diverse came from the forearm and the most similar were from those living behind the knees, in the elbow, and behind the ear. "After completing this initial survey, researchers aim to establish a bacterial baseline so as to better treat skin diseases, such as acne or eczema, where bacterial populations might be out of whack," says 60 Second Science. A GenomeWeb Daily News story reports more fully on the work.

BU's Jim Collins has created two synthetic genetic networks in E. coli that can count cellular events. These can count up to three induction events: "the first, a riboregulated transcriptional cascade, and the second, a recombinase-based cascade of memory units," says the abstract. In a perspective, Christina Smolke from Stanford says that synthetic counters would enable many applications, such as regulating cell death after a specific number of cell division cycles.

Jin Billy Li was first author on a paper out of George Church's Harvard lab that used DNA capture and sequencing to survey RNA editing sites genome-wide. Screening more than 36,000 computationally predicted sites, they identified 239 potential editing sites and validated 14 out of 18 randomly chosen ones by sequencing. These particular genes related to synapse, cell trafficking, and membrane functions.

Scientists led by Kevin Verstrepen looked at how tandem repeats in yeast genome promoters affect transcription and, thereby, phenotypic evolution. Mapping all the repeats in the S288C strain of the S. cerevisiae genome revealed that of the approximately 5,700 promoters in the genome, 25 percent contain at least one tandem repeat. He also found that promoters containing TRs showed significantly higher amounts of expression divergence than promoters without TRs when they compared three different yeast species.

The Scan

Pig Organ Transplants Considered

The Wall Street Journal reports that the US Food and Drug Administration may soon allow clinical trials that involve transplanting pig organs into humans.

'Poo-Bank' Proposal

Harvard Medical School researchers suggest people should bank stool samples when they are young to transplant when they later develop age-related diseases.

Spurred to Develop Again

New Scientist reports that researchers may have uncovered why about 60 percent of in vitro fertilization embryos stop developing.

Science Papers Examine Breast Milk Cell Populations, Cerebral Cortex Cellular Diversity, Micronesia Population History

In Science this week: unique cell populations found within breast milk, 100 transcriptionally distinct cell populations uncovered in the cerebral cortex, and more.