(left to right): ISTOCK.COM/EPICUREAN; JEFFREY D. ALLRED/THE DESERET NEWS/AP; SYLVAIN CORDIER/GAMMA-RAPHO/GETTY IMAGES

Top stories: a gene for marathons, piercing the haze on ammonia, and a health plan for the ‘Iceman’

This broken gene may have turned our ancestors into marathoners—and helped humans conquer the world

A new study is offering some clues on how humans developed endurance for long-distance running. Twenty years ago, researchers found that unlike other primates, humans carry a broken copy of a gene called CMP-Neu5Ac Hydroxylase (CMAH). Now, a team of researchers has found that mice with the human version of the CMAH gene ran 12% faster and 20% longer than the other mice when placed on tiny treadmills. The mice with the human version of CMAH had more tiny blood vessels branching into their leg muscles and after exercising, those muscles kept contracting much longer than those from the other mice.

Ammonia, a poorly understood smog ingredient, could be key to limiting deadly pollution

Ammonia—the colorless, sharp-smelling, and eye-watering gas—is getting a closer look from researchers because of its role in producing deadly air pollution. Despite its abundance, however, ammonia is poorly understood because its molecules are “sticky” and eagerly combine with other compounds, making it difficult for monitoring instruments to capture them. But new ground-, air-, and space-based sensors are helping bring the sources, movements, and fate of ammonia into clearer focus. The improved monitoring comes as some nations, including the United Kingdom, are moving to slash ammonia emissions.

Monarchs that ‘drop out’ of the migration game pick up more parasites

Monarch butterflies have increasingly been dropping out of their mass annual migration to Mexico, and have instead been spending their time as year-round residents in the southern United States, enticed by tropical, nonnative strains of milkweed planted by gardeners. However, by examining more than 500 monarchs from nine different sites in Texas, researchers found migratory monarchs that stopped at resident sites were 13 times more likely to be infected by deadly parasites than other migrants.

Universities are worse than drug companies at reporting clinical trial results

Drug companies have taken a lot of heat over the years for not promptly reporting results from clinical trials, but a new study suggests academics may be even worse. Nearly nine in 10 university clinical studies fail to report results in the European Union Clinical Trials Register within the required 1-year time frame, a team from the University of Oxford in the United Kingdom reports. The worst offenders include the Charité University Hospital in Berlin and the Ludwig-Maximilian University Hospital in Munich, Germany, as well as Sweden’s Karolinska Institute in Stockholm.

5000-year-old ‘Iceman’ may have benefited from a sophisticated health care system

By taking a look his tattoos, scientists have found that Ötzi, the 5300-year-old “Iceman” discovered frozen in the Italian Alps in 1991, may have lived in a society with well-developed medical practices. Lines and dots were tattooed directly over his wrist and ankles which suffered from degenerative diseases, and many correspond to traditional acupuncture points.