What types of research papers move a scientist to turn from test tube or data-crunch to spread the word on social media? Here are some papers that saw Twitter activity from researchers in early April.

Lionfish took a bite of Twitter attention at the start of this month in a paper that reveals some unintended effects of population-control measures that could undermine future efforts. Isabelle Côté at Simon Fraser University in Burnaby, Canada, and her team, looked at what happens after invasive predatory lionfish (Pterois volitans/miles) were culled at coral-reef sites in the Bahamas. The effects on surviving fish were marked: they became less active and hid deeper in the reefs during the day compared with fish in reefs where no culls took place. The wary lionfish also seemed able to spot approaching divers from a greater distance. As Côté pointed out on Twitter, these changes in behaviour could lead to underestimating the size of the lionfish population.

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Côté, I. M. et al. PLoS ONE 9, e94248 (2014)

Heading south to California, Ash Alizadeh, Maximilian Diehn and their colleagues at Stanford University had cyber tongues wagging over their method to measure tumour DNA levels in the blood of patients with cancer. The researchers built a library of short DNA strands carrying genetic mutations linked to non-small-cell lung cancer, which they used to screen blood samples from people with the disease. They managed to detect the presence of tumour-cell DNA in all the patients they tested who had mid- to late-stage tumours. They also found that the level of tumour DNA could predict how the disease would eventually progress in a small number of patients. The team hopes that this will lead to a sensitive and low-cost method for monitoring responses to treatment as well as maybe for screening.

Newman, A. M. et al. Nature Med. http://dx.doi.org/10.1038/nm.3519 (2014)

Perhaps this next finding drew attention because it could explain why your brother is overweight and you aren't (or vice versa). Mario Falchi and Philippe Froguel at Imperial College London and their team found a genetic link between carbohydrate metabolism and obesity. They analysed genomes from the fat tissue of Swedish families with obese and non-obese siblings — and found that a higher body mass index was associated with fewer copies of the gene that encodes salivary amylase, an enzyme that breaks down starch into sugars. People with fewer than four copies of the gene had a roughly eightfold increase in obesity risk compared with individuals with more than nine copies.

Falchi, M. et al. Nature Genet. http://dx.doi.org/10.1038/ng.2939 (2014)

Further work looking at familial relationships highlights everyone's true individuality. “That each of us is truly biologically unique, extending to even monozygotic, 'identical' twins, is not fully appreciated,” writes Eric Topol in a review that outlines the myriad ways in which humans — every one of us — differ. And not just at the level of DNA sequence, but also in the chemical tags on genes that govern regulation, the RNA molecules that our cells manufacture, the metabolic pathways inside tissues and the microbes that reside in our guts. Topol, of the Scripps Research Institute in La Jolla, California, believes that this offers “unprecedented opportunity” to craft individualized strategies to prevent and treat disease.

Topol, E. J. Cell 157, 241–253 (2014)

Scientists are not above a touch of toilet humour, which could be why a paper on anal gas evacuation got researchers tweeting. Fernando Azpiroz of the Vall d'Hebron University Hospital in Barcelona, Spain, and his team set out to divine what happened to gut microbes when subjects — either healthy or with gastrointestinal issues that include excessive flatulence — consumed a gas-inducing diet. Microbial populations in the patient group were disturbed, showing reduced diversity and fluctuations in specific microbial taxa, but remained stable in the healthy group.

Manichanh, C. et al. Gut 63, 401–408 (2014)

Methane also made its mark in a paper looking back some 250 million years. Daniel Rothman of the Massachusetts Institute of Technology in Cambridge and his colleagues offer a different take on the end-Permian extinction, a 20,000-year period that saw more taxa die off than at any other time in the fossil record. A rise in carbon dioxide levels at this time (thought to have caused the extinctions) was proposed to be due to volcanic activity. From their analyses of carbon isotopes, phylogenetics and sediments, the authors instead implicate the evolution of a new methane-generating biochemical pathway in microbes.

Rothman, D. H. et al. Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1318106111 (2014)

Sticking with times past, the early Cambrian proved a talking point when it came to a well-preserved arthropod cardiovascular system. Scientists used to believe that only the guts of early arthropods could survive fossilization — but then researchers found traces of brain in some fossils. Now, a team led by Xianguang Hou of Yunnan University and Nicholas Strausfeld of the University of Arizona in Tucson adds its findings to that diversity. The authors report what they interpret as a tidy, bilaterally symmetrical circulatory system in the 520-million-year-old early Cambrian fossil Fuxianhuia protensa, collected in China's Yunnan province.

Ma, X., Cong, P., Hou, X., Edgecombe, G. D. & Strausfeld, N. J. Nature Commun. 5, 3560 (2014)