Abbreviated Science Round-up: De-extinctions, same sex mouse parents, even better LEDs

A footnote to the extinct revival effort. Many of the animals being considered for return to the wild—from the Tasmanian thylacine to the dodo—were quite simply killed by people. To suggest that scientists are “playing God” in attempting to bring them back is to admit that people already played God, or worse, in killing them to begin with. Frankly, I find the idea of living passenger pigeons, wooly mammoths, and the whole great gamut of the past delightful. I’m a geologist who specialized in evolution and spent six years on dinosaur digs. I want some damn trilobites in my fish tank.

My only concerns are that efforts to revive vanished organisms don’t distract from efforts to save those still with us or give the illusion that extinction is somehow “okay” because “we can always bring them back.” And that any animals restored to the world have a place that’s not my aquarium, or some other similar little jar for our amusement. Bring them back … because they’re beautiful, and we could always use more of that. For the same reason we should fight — tooth, nail, wing, and claw — to preserve every ounce of the diversity that remains.

And there’s one other real concern that I share.

Shapiro says that’s not enough. Eventually, she says, gene-editing tools may be able to create a genetic copy of an extinct species, “but that doesn’t mean you are going to end up with an animal that behaves like a passenger pigeon or a woolly mammoth.” We can understand the nature of an extinct species through its genome, but nurture is another matter. With no living woolly mammoths or passenger pigeons to model social behavior, who will teach these genetic replicas how to behave like their kind?

“We are going to need a new biology and new names for all this,” Soares says.

National Geographic: Same-sex mouse parents give birth via gene editing

Gene editing is good for more than bringing back extinct species. In a widely publicized experiment revealed this week, it also held open a tantalizing glimpse of ways it might affect some that are very much alive.

Using gene editing and stem cells, researchers in China have helped mice of the same sex bear pups. While this feat has been accomplished before with mouse moms, the new study marks the first time that pups from pairs of male mice were also carried to full term.

But, as with the first experiments in cloning, there are factors here that need to be better understood before this is more than an experiment. And certainly before it is extended that seems the most obvious potential use of the technique.

The technology is far from ready for the leap to humans. Though mice pups born from two females appeared healthy and bore their own young, pups with two papas died soon after birth. Of the 12 born, just two survived more than 48 hours.

Pointing out one other potential use — the last male Northern White Rhino died earlier this year. But two females remain. Saving the subspecies in this way may seem like a longshot, but it’s better than attempting the technologies of the previous article.


Bloomberg: The end of coal may be closer than it seems

With Hurricane Michael serving as a fresh reminder and a growing stack of recent articles showing that climate change is hitting with devastating force, the need to address the issue is increasingly urgent and increasingly frustrating. Things are bad. Things are very, very bad. But they are not yet hopeless.

The world’s electrical utilities need to reduce coal consumption by at least 60 percent over the two decades through 2030 to avoid the worst effects of climate change that could occur with more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming, the Intergovernmental Panel on Climate Change announced Monday.

Such a target seems wildly ambitious: Even Bloomberg New Energy Finance, which tends to be more optimistic than other analysts (and more accurate) about the speed of energy transition, expects coal-fired generation to increase by 10 percent over the period. 

Both numbers seem shocking number. Except … coal is already crashing in much of the world. Despite Donald Trump’s lies, damn lies, and fake statistics, coal isn’t making a comeback. And won’t make a comeback in the US. Still there are countries, some of which may be unexpected, like Australia, where coal is hanging on. And coal is being pitched to areas where the economy is expanding rapidly as a “cheap” way of increasing available electricity.

Like the cigarette industry, the merchants of doubt in coal have turned from trying to market their product to Americans, and concentrated on peddling it overseas. But this remains a problem that can be overcome.

Across Europe and the U.S., the decline in coal output recently has averaged close to 5 percent a year. If the world as a whole can reach 7 percent a year, it would be on track to meet the IPCC’s 2030 target.

The conventional wisdom is that this isn’t possible, as rising demand from emerging economies, led by China and India, overwhelms the switch from fossil fuels in richer countries. That may underestimate the changing economics of energy generation, though.

A lot of current projections and plans were made when solar and wind were orders of magnitude more expensive. As their price continues to fall, the need for coal plants declines. Many plants that were on the drawing board have been scratched, and more are soon to follow.

Nature: LED technology breaks performance barrier

Despite conservatives going bonkers to preserve energy-wasting, short-lived, inefficient incandescent light bulbs, LED have carried the market. You can pick up LED bulbs at the local hardware store for pennies more than the few surviving old-school bulbs, they’ll last years longer, and they’ll use a fraction of the energy. LEDs have also replaced even larger tubes — the ones in our television sets (except for mine, which was made in 1979). 

But they can still get better. 

In this issue of Nature, two papers report what could be the birth of a new family of LEDs based on semiconductors called perovskites. Remarkably, the efficiencies with which the perovskite LEDs (PLEDs) produce light from electrons already rival those of the best-performing OLEDs, and have been achieved in less than four years since the report of the first PLED — suggesting that there is plenty of room for even further improvement in their performance.

These new LEDs promise not only better performance, they could enormously lower the power demands of the most power hungry component of most portable devices.

Perovskites in this case aren’t really the mineral—a calcium and titanium oxide—but metal halide perovskites, usually compounds like (take a breath) methylammonium lead trihalide. They’re showing up more and more in highly efficient solar panels, in energy storage and transmission … in just about every area of electronics. Other compounds have had a similar star turn but never turned out to lead to practical products, but perovskites seem like, seem like, the real deal. In the case of displays, perovskites may make “cheap video wallpaper” a real possibility. Stay tuned.


Nature: Crime scene DNA analysis

Thanks to everyone checking out their genetic ancestry, there’s a growing database available to law enforcement that lets them do a first-level scan of any location for … white people.

It could soon be possible to search crime-scene DNA for links to nearly all people of European descent who live in the United States. A new study reveals how easy it is to identify a particular person on the basis of their DNA, by connecting them to very distant relatives who have chosen to use consumer-genetics services. The technique works best for Americans with European ancestry, because they make up the vast majority of those services’ customers.

There are definitely some times when this could help.

From the mid 1970s to the late 1980s, a string of burglaries, sexual assaults and murders committed in California were attributed to an unknown person dubbed the Golden State Killer or the East Area Rapist. The case went cold, but in April 2018, police arrested a suspect named Joseph James DeAngelo. He was identified as a suspect, in part, by matching crime-scene DNA to genetic profiles posted by his distant relatives on the genetic-genealogy website GEDmatch, which allows people to upload genetic profiles obtained from consumer genetic companies to search for relatives.

Which doesn’t mean that the idea of being picked up for leaving some cells in a room is a little disturbing.

Nature: “Polygenic risk scores” could greatly improve genetic testing for disease

Some diseases are directly tied to only a few points on the genome and easily diagnosed even with consumer grade tests. But many — even most — are not.

6.6 million — that’s how many spots on the human genome Sekar Kathiresan looks at to calculate a person’s risk of developing coronary artery disease. Kathiresan has found that combinations of single DNA-letter differences from person to person in these select locations could help to predict whether someone will succumb to one of the leading causes of death worldwide. It’s anyone’s guess what the majority of those As, Cs, Ts and Gs are doing. Nevertheless, Kathiresan says, “you can stratify people into clear trajectories for heart attack, based on something you have fixed from birth”.


Science: French aims at cutting pesticide use in half are falling short

In 2008, the French government announced a dramatic shift in agricultural policy, calling for pesticide use to be slashed in half. And it wanted to hit that target in just a decade. No other country with as large and diverse an agricultural system had tried anything so ambitious. Since then, the French government has spent nearly half a billion euros on implementing the plan, called Ecophyto. It banned numerous pesticides, created a network of thousands of farms that test methods of reducing chemical use, improved national surveillance of pests and plant diseases, and funded research on technologies and techniques that reduce pesticide use. Although the effort helped cut demand on many farms in the network, national use increased by 12%. Officials are now finalizing a revised plan. Some observers are already skeptical.

Despite the failures of the initial plan, techniques that resulted including more targeted use of pesticides and use of biological controls, have spread to many countries, including the US. Even if the revised plan falls short again, it’s likely to generate a beneficial outcome.

Materials science

Science: Using puffed rice to simulate structural failures

No. Seriously. This is science, not some guys screwing around with excess breakfast cereal.

When brittle porous media interact with chemically active fluids, they may suddenly crumble. This has reportedly triggered the collapse of rockfill dams, sinkholes, and ice shelves. To study this problem, we use a surrogate experiment for the effect of fluid on rocks and ice involving a column of puffed rice partially soaked in a reservoir of liquid under constant pressure. We disclose localized crushing collapse in the unsaturated region that produces incremental global compaction and loud audible beats. These “ricequakes” repeat perpetually during the experiments and propagate upward through the material. The delay time between consecutive quakes grows linearly with time and is accompanied by creep motion. All those new observations can be explained using a simple chemomechanical model of capillary-driven crushing steps progressing through the micropores.

I am going to shout “ricequake!” every time I plunge in the spoon.


PNAS: Where do little black truffles come from?

Or even big black truffles? Just what are these hog and/or dog sniffed out pricey things?

In the winter of 2016, ecologist Laure Schneider-Maunoury went truffle hunting in France. But she wasn’t looking to add the fungus to a culinary delicacy. Schneider-Maunoury, a graduate student at the National Museum of Natural History in Paris, was on the hunt for the truffle’s missing father, the form that contributes genes to generate the aromatic, edible fruiting body. Researchers still don’t know where these paternal truffles live or how the maternal and paternal partners find each other.

It’s a mystery with major implications for farmers, chefs, and foodies enamored with the pungent, expensive black truffle (Tuber melanosporum). Slivers of the fungus, which can run hundreds of dollars per pound, grace dishes from risottos to pizzas. Although farmers can raise truffles in orchards of oak or hazelnut, where the fungus joins with the tree roots, the crop remains what some call “protodomesticated” because growers can’t control its reproduction. Complicating matters, yields from truffle grounds have plummeted in the past century, likely a result of dwindling habitat.

I like the idea of a truffle farm that looks like nothing but an untouched woodland of oak and hazelnut. When they figure this out, sign me up.


As usual, the image is from Andy Brunning at Compound Interest. Visit Andy’s site for more and to get a larger, more detailed version of this week’s image.


This is one of those weeks where I had a build up of non-journal material, but I’m going to backfill with some articles. Hang in there.

Continue reading...