In this week's Science, researchers from all over the globe urge caution in laboratory experiments involving gene drive systems, which promote the spread of genetic elements throughout populations, and highlight the risk associated with their accidental release. Such systems have already been built using CRISPR/Cas9 genome-editing technology, and while barrier methods are routinely employed in such experiments, the researchers suggest a number of additional confinement measures that can be taken. They also suggest that gene drive approaches to genome engineering should be limited to specific cases and offer ideas for alternative strategies with lower risks should modified organisms escape.
Also in Science, a team led by investigators from the Weizmann Institute of Science report on how looking at the ratio of gene copies in replicating bacteria populations can reveal patterns that are predictive of microbiota growth. Specifically, the researchers discovered that the pattern of metagenomic sequencing read coverage for different microbial genomes contains a single valley and single peak, with the latter coinciding with the bacterial origin of replication. They also show both in vivo and in vitro that the ratio of sequencing coverage between the peak and valley, meantime, can provide a quantitative measure of a species' growth rate. For certain bacterial species, coverage rations were also found to correlate with the manifestation of inflammatory bowel disease and type II diabetes.