Welcome back to Axios Science. Please share us with your friends and colleagues, and as always tell me what you think. I'm at [email protected] or just hit reply to this email. Don't forget the check out the stream all week for science news.

Axios' Shane Savitsky and Andrew Witherspoon created this visualization showing how obesity and being overweight has grown in prevalence over the past three decades in all but a few countries.

Key takeaway: Nearly 40% of the 4 million deaths in 2015 linked to excess body weight occurred among people who weren't yet classified as obese. Simply being overweight can be a serious health risk.

Read more here.

• DNA storage: Scientists recorded a GIF on living bacterial DNA. Information has been encoded in DNA before but never in a live, replicating cell. Next: microbes as hard drives.
• Mozzie map: Watch the spread of disease-carrying mosquitoes in the U.S. over the last two decades.
• Genetics of gaze: A new study suggests genes influence eye contact, a finding with implications for understanding autism.
• Self-control: A new study suggests ravens can plan ahead, a behavior thought to be limited to humans and other great apes.

Influenza, Ebola, HIV — these viruses all made the jump from chickens, bats, and chimpanzees to us. Most viruses that infect humans start this way. Some don't become contagious, but others — take the 1918 flu that killed at least 20 million people — rapidly spread across continents.

We asked four researchers where the next disease to threaten us might emerge from:

• Thumbi Mwangi, veterinarian, Washington State University: Control small diseases to be ready for big ones.
• Anne Rimoin, epidemiologist, UCLA: Watch where people and animals interact.
• Justin Lessler, epidemiologist, Johns Hopkins University: It's not where a virus comes from but how it becomes contagious.
• Kevin Olival, ecologist, EcoHealth Alliance: There are 5,000 places to look.

• The reaction to New York Magazine's climate change horror story. Top picks: Mashable's Andrew Freedman on what they got wrong and Grist's Eric Holthaus on why scare tactics don't work.
• Road trip, New Mexico: Wishing I could be there for the Santa Fe Institute's InterPlanetary Project events. Their central question: What can humanity be proud of? (Note: This is meant to be an exercise in optimism.)
• Repeat, repeat, repeat: Researchers will redo nine studies, including one from 1960, that have heavily influenced medicine and psychology but have also been called into question. The work is motivated by an ongoing and important debate about studies in these fields not being replicated.

Axios' Erin Ross writes...On Wednesday, scientists reported that they had successfully encoded a GIF in the DNA of a living bacteria. They didn't just choose any GIF — it came from the sequence The Horse In Motion, a series of pictures captured by photographer Eadweard Muybridge in 1878.

The question behind the sequence: Leland Stanford, a railroad tycoon and avid horse racer, wanted to settle a debate about horse locomotion: When a horse gallops, do all of its feet ever leave the ground at the same time? It may seem like a strange question, but since a horse's legs move so fast, no one knew.

How they did it: Muybridge set up an array of cameras — each specially designed to only require a split-second exposure — and trip wires. As the horse ran by, each stage of its stride was captured.

The legacy: The resulting images answered the question (yes, all four horse feet leave the ground), but it also created one of the first animations. Muybridge went on to capture the motion of numerous other animals, including birds in flight, running predators, and humans. His images could be considered the predecessors of today's slow-motion image capture, reducing the world's motion to single frames that can be stopped, slowed down, and rewound.

On Monday night around 10 p.m., NASA's Juno probe flew 5600 miles above Jupiter's Great Red Spot, bringing us closer than ever to the planet's iconic storm. By Wednesday afternoon, citizen scientists around the world had processed, merged, and enhanced Juno's raw images to create pictures of the giant storm that humans have been watching for nearly two centuries.

Correction: Last week's newsletter stated there had been a 30% decline in the American horseshoe crab population over the past 40 years. While the species was placed on the "vulnerable" list last year, that decline is projected over the next 40 years. My apologies.