Our family tree may be a lot messier than we thought - Axios
Featured

Our family tree may be a lot messier than we thought

Different perspectives of a molar found at the Siberian cave Denisova. Credit: Slon et al. Sci. Adv. 2017

The story of human evolution goes something like this: humans evolved in Africa 300,000 years ago and about 70,000 years ago, a small group moved to other continents, giving us today's populations.

But two new studies suggest our family tree may be much more tangled than we previously thought. Scientists in Europe report evidence that modern humans and Neanderthals interbred much earlier than we thought, and that Neanderthals and their sister group of Denisovans may have had ample time to mingle.

The studies:

  • We knew humans had Neanderthal DNA from our entrance into Europe, but we didn't know that Neanderthals already in Europe had a human genetic legacy, too. Their DNA shows complex ancestry — their nuclear DNA (inherited from both parents) connects them with Denisovans, a group that lived thousand of miles away in the Siberian cave Denisova, whereas their mitochondrial DNA (passed on only from mothers) links them to humans. New DNA evidence from a 120,000-year-old Neanderthal fossil suggests Neanderthals inherited their mitochondrial DNA from an ancestor who lived 270,000 years ago. A revised picture: Neanderthals and Denisovans had a common ancestor half a million years ago that gave rise to Denisovans in Asia and to Neanderthals in Europe. More 270,000 years ago, African humans closely related to us migrated into Europe and bred with Neanderthals, that carried their DNA.

"But somewhere in prehistory, at least one female human from Africa must have carried the child of a male Neanderthal," Carl Zimmer writes in the NYT.

  • In a separate study, Svante Paabo and his team report the discovery of a "baby tooth" in Denisova. Unlike Neanderthals, the history of the Denisovans is largely unknown due to a sparse fossil record. (Until now, scientists have only found bone fragments of three Denisovan individuals.) The newly discovered molar is from a fourth Denisovan, a young female, and is believed to be at least 100,000 years old — 20,000 years older than the other Denisovan fossils. That means they may have had more time to mingle with Neanderthals than previously thought.

Featured

More STD cases recorded in 2016 than ever before

The bacteria which causes Chlamydia, the most prevalent STD in 2016. Photo: CDC via AP

The Centers for Disease Control and Prevention recorded over 2 million cases of STDs in 2016, the highest-ever number. The most prevalent disease, with 1.6 million cases, was chlamydia, followed by gonorrhea, with 470,000 cases.

Why it matters: The number of reported cases is on the rise. There were 4.7% more cases of chlamydia in 2016 than 2015, and an 18.5% increase in gonorrhea during that time period. Cases of syphilis, which are much less prevalent than chlamydia or gonorrhea, saw a 17.6% bump from 2015 to 2016.

Featured

Study: Autism is rooted mostly in genetics

People commemorating World Autism Awareness Day (April 2) in Brazil. Photo: Felipe Dana / AP

The risk of developing autism is 83% genetic and 17% due to environmental factors, according to a new model, TIME reports. Scientists studied sibling pairs — ranging from half siblings who share one biological parent to identical twins who share 100% of their DNA — and tracked diagnoses of autism among them, per the study. They also accounted for the fact that siblings may be diagnosed at different times.

Why it matters: The new model adds perspective to the debate over whether the disorder is rooted in genetics or environmental factors. Previous studies of just twins have found a 90% correlation between developing autism and genetics.

Featured

Drug company reels from failed Alzheimer's drug

A highly watched Alzheimer's drug failed its clinical trial. Photo: Evan Vucci / AP

The experimental Alzheimer's drug intepirdine failed a crucial clinical trial, Axovant Sciences said Tuesday. The bad news crushed Axovant's stock by more than 70%. The failure is a major disappointment for people who thought Axovant had a promising therapy for a brain disease that routinely eludes promising therapies.

Go deeper: Forbes profiled Axovant in 2015.

Featured

A fungus is threatening the world's chocolate

A worker holds a handful of dry cacao beans ready to sell at the Agropampatar chocolate farm Co-op in El Clavo, Venezuela. Photo: Fernando Llano / AP

Around the world, there is a wide variety of trees bearing cacao pods of different sizes, shapes and colors that can be used to produce chocolate. But as The New York Times' Myles Karp explains, only a few cacao types are broadly cultivated, which narrows the gene pool and puts the crop at risk for disease and environmental changes.

Why it matters: These challenges have made cacao less attractive to producers even though demand for chocolate is increasing — that could mean a shortage in the future.

The threats

  • One of the greatest threats to cacao is the development of a fuzzy white fungal coating, called monilia or frosty pod rot. The fungus spread across Costa Rica during the 1980s, and eventually led exports of cacao beans to plummet 96%.
  • "For me, the cacao industry is in permanent risk, because intentionally or unintentionally this disease could be spread in just one flight," said Wilbert Phillips-Mora, head of the Cacao Genetic Improvement Program at C.A.T.I.E. He added that the uptick in global travel and commerce in the developing world has created new avenues for infection.
  • Climate change could affect the ability of plant pathogens to infect plants and make plants more susceptible to infection.

A potential solution

  • Phillips-Mora studied the "most naturally tolerant and productive cacao trees" in the early 1980s, and by 2006 found a way to breed 6 hybrid cacao trees that on average produce about 3 times more than the standard types.
  • One of his hybrids, called C.A.T.I.E.-R6 experiences roughly a 5% frosty pod rot infection rate, compared to 75% for a control variety. C.A.T.I.E. hybrids are now grown in all of Central America, as well as in Mexico and Brazil.
  • The silver lining: "Whatever fungal mutation may arise, wherever drought may strike, however chocolate tastes may change — there will likely be cacao genes somewhere in the collection that can form the basis of new hybrids to meet future challenges," writes Karp.
Featured

Irma captured America's attention more than other storms

It's been a busy hurricane season, with three powerful hurricanes hitting and one just missing U.S. territories. Here's when and how often Americans' searched Google each of them.

Data: Google Trends; Chart: Lazaro Gamio / Axios

Why it matters: Irma received the most attention, according to Google, likely due to reports it'd be the most powerful hurricane ever to hit the U.S. Meanwhile, Puerto Rico has been devastated by Hurricane Maria, but interest from the U.S. is substantially less than during both Harvey and Irma.

Note: This search data does not include Puerto Rico. Puerto Ricans were highly interested in both Hurricane Irma and Hurricane Maria, with the least interest in Harvey.

Featured

Panda habitat is getting smaller and more fragmented

Although giant panda's populations are rising, their conservation status is still uncertain, according to a study published Monday in Nature Ecology and Evolution. Researchers found the panda's habitat is smaller and more fragmented than it was when the bear was first put on the endangered species list in 1990.

Why it matters: Thanks in large part to China's efforts to restore the bamboo-eating bear's habitat, the panda population has been growing, and last year the bear was reclassified from endangered to vulnerable by the IUCN. But if that same habitat is becoming more fragmented, the improvements made might not be enough to support a growing population.

What they did: The researchers compared satellite images from 1976, 1988, 2001 and 2013.

  • From 1976-2001, the habitat increased by 4.9 percent, and has only gone up by 0.4% since 2001.
  • From 1976-2001, the average size of a roadless forest patch decreased by 24%, and grew 1.8% since 2001.

The bottom line: Moving pandas from the endangered to threatened list last fall was "a recognition of panda conservation success so far. But pandas are still facing threats, especially climate change. It does not mean that panda conservation should stop," study author Jianguo Liu told Ben Guarino of the Washington Post.

Featured

The political and environmental battle over shark fins

Shark fin protesters in Hong Kong. Photo: Kin Cheung / AP

A new study has indicated that banning the possession of shark fins in the United States might actually hurt shark conservation efforts in the long run as other less-regulated countries step in to fill the void, per the AP.

Why it matters: There's a concerted effort in Congress, spearheaded by a bill sponsored by Sen. Cory Booker, to ban shark fins in the U.S., piggybacking off the success of a similar ivory ban that was instituted last year.

Shark fins? They're popular in soup across Asia, especially China, which is by far the world's largest consumer of the fins.

The problem: Caught sharks are often "finned," where the whole — often still alive — shark is tossed back after just the fin is removed. Finning is illegal in the U.S. but remains widely practiced around the world.

The study's argument: Because the U.S. is a leader in responsible shark fishing, removing the country from the trade altogether could be to the detriment of shark conservation efforts as other countries would likely attempt to meet demand by finning rather than sustainable tactics that utilize the whole shark.

The response from environmental groups: NOAA has investigated hundreds of allegations of finning in the U.S. this decade. A representative for Oceana, a marine conservation non-profit, told the AP: "Yes, we are better, but just because we are better doesn't mean we are good. There are other threats facing sharks, but this [proposed ban] is a very important step in the right direction."

Expert Voices Featured

How AI can help doctors — to a point

Illustration: Lazaro Gamio / Axios

There's a lot of talk about how artificial intelligence can change the practice of medicine, with new initiatives being launched to take advantage of the technology (we wrote about one here). But it's already clear that there are limits to how useful it will be in the doctor's office.

The rough consensus from medical experts: It may be able to help with some diagnoses and free up time for doctors by handling some of the time-consuming tasks. But it will never replace what's unique about a doctor listening to a patient. We asked four medical experts for their views.

Featured

Puerto Rico's hurricane recovery will take years

A line to buy bread in Yabucoa, Puerto Rico, after Hurricane Maria passed through the island. Photo: Carlos Giusti / AP

Last week, Hurricane Maria, which came right on the heels of Hurricane Irma, ripped through Puerto Rico, killing at least 13 people and wiping out electricity on the entire island. Strapped for resources, Puerto Rico now faces a steep recovery and officials say residents may not have power for 4 to 6 months.

The bottom line: Hit by back-to-back hurricanes and $73 billion in debt, Puerto Rico is dealing with a crisis of historic proportions. The U.S. federal government will have to take a significant role in the recovery process to give the U.S. territory a chance at bouncing back.

  • The state-run power company in Puerto Rico is broke, along with several other government agencies, due to the debt crisis.
  • President Trump has pledged the full support of the U.S. government in Puerto Rico's recovery and said he will visit the island.
  • The port of San Juan is open and accepting shipments of food, water and generators.
  • Puerto Rico's federal control board has authorized $1 billion for hurricane relief, but Gov. Ricardo Rossello has said he will ask for more. The damage could top $30 billion, per MarketWatch.
  • FEMA response teams have already been landing in Puerto Rico and begun search and rescue missions. FEMA also said it would bring satellite phones to towns and cities to use while the telephone and power lines are repaired.
  • 70,000 people were evacuated from areas downstream of the Guajataca Dam, which officials said had cracked.
Featured

What to watch for with gene therapy

Image: cover of this week's Barron's Magazine

"Gene Therapy Is Nearing a Major Breakthrough: Therapies that replace faulty genes with healthy ones to cure deadly diseases are generating exciting lab results. How to invest in a hot sector," by Barron's Andrew Barry:

"The goal of replacement gene therapy is to replace faulty genes with normal ones, in the hope of producing significant benefits or even cures. The process involves packaging healthy genes into neutered viruses, ... which then act as vectors delivered in a single dose either into the bloodstream or .. where the disease is."

Why it matters: "The first regulatory approval for this technology could come [from the FDA] as soon as January ... Other approvals could follow, igniting even greater interest in the field — and in the shares of several biotech companies making impressive headway in clinical trials."

Free link for Axios readers. With graphic, "How replacement gene therapy works."

P.S. "Dow 1,000,000: Warren Buffett predicts that the benchmark will hit that number by 2117." (It closed yesterday at 22,000.) Free link for Axios readers.