Week in Review: July 6–10

Passenger mutations in mouse models; evolution of kin discrimination in a bacterium; are liquid biopsies ready for prime time?

Jul 10, 2015
Tracy Vence

Liquid biopsies

ISTOCK.COM/NANOSome pregnant mothers whose blood is being screened for fetal chromosomal abnormalities are instead finding out that they, themselves, have cancer. That’s because some tumors shed fragments of DNA, vesicles, or even whole cells into a patient’s bloodstream.

“In the majority of these tumors, even low grade ones, we found we could use an individual’s blood as a surrogate for studying tumor biology,” cytogeneticist Joris Vermeesch of the KU Leuven Center for Human Genetics in Belgium told The Scientist.

Now, several companies are working to develop tests that screen for circulating tumor DNA, exosomes, and cells. At this point, these assays are only useful for certain types of cancer, but the hope is that these tests can help clinicians catch the disease early and inform treatment decisions.

“Detecting the presence of occult disease that hasn’t yet shown up in clinical or radiologic grounds so we can implement therapies which could be curative [if begun early enough],” said Bert Vogelstein of the Johns Hopkins School of Medicine in Baltimore, Maryland.

Extra mutations

FLICKR, STEFANOUnintentional mutations may have skewed the results of countless studies involving mutant mouse models, researchers from Ghent University in Belgium reported in Immunity this week (July 7). While the extent to which these so-called passenger mutations may affect experimental results varies, the researchers found that such mutations affected nearly two years’ worth of their own work.

The result “empowers the scientific community to look a little closer” at the transgenic mice they are studying, Genentech’s Soren Warming, who was not involved in the work, told The Scientist.

Myxococcus xanthus, myself

FRANCESCA FIEGNAThe self-organizing bacterium Myxococcus xanthus can recognize kin among strains that evolved from a common ancestor under different laboratory conditions, according to a study published in PNAS this week (July 6). Finding that M. xanthus could identify genetically related individuals even within its own species, scientists from ETH Zürich and their colleagues suggest that kin discrimination is not necessarily a result of interspecific competition.

“Despite [kin discrimination] being common, it is unclear whether these abilities are adaptations that act to limit cooperation to close relatives (who share and thus pass on the same genes) or whether they evolved for some other function and only incidentally have these functions,” Elizabeth Ostrowski, who studies kin discrimination in social amoebae at the University of Houston but was not involved in the work, wrote in an e-mail to The Scientist.

Botanical art

MINDY LIGHTHIPETrained as a studio artist and educator, botanical illustrator Mindy Lighthipe of the University of Florida takes a scientific approach to her work. She sometimes spends a year or more observing plants and animals before beginning to draw them. “When I discover something new, I want to learn as much as I can about it,” Lighthipe told The Scientist.

See a selection of Lighthipe’s illustrations, here.
 

Other news in life science:

Report: WHO Unfit for Public Health Emergency
An international panel concludes that the World Health Organization is not prepared to handle another emergency like the Ebola outbreak in West Africa.

Vaccine Fraudster Gets Jail Time
The researcher who spiked rabbit blood with human antibodies to make an HIV vaccine look more effective is sentenced to 57 months in prison and must repay his National Institutes of Health grant.

Bad Blood Between California Universities
The University of California, San Diego, is suing the University of Southern California and a former employee over alleged data theft, among other charges of academic animosity.

Ebola Risk in Liberia?
Authorities report three cases of Ebola in Liberia, which was declared free of the virus in May.

Big Data Problem
Scientists estimate that, in the next 10 years, the data needs of genomics will outpace those of astronomy and some social media.