Researchers at the Chinese Academy of Sciences were able to make baby mice with two moms and no dad. "The aim of the Chinese researchers was to work out which rules of reproduction they needed to break to make baby mice from same-sex parents," reports the BBC. "That in turn helps understand why the rules are so important." From the report: It was easier with double mums. The researchers took an egg from one mouse and a special type of cell -- a haploid embryonic stem cell -- from another. Both contained only half the required genetic instructions or DNA, but just bringing them together wasn't enough. The researchers had to use a technology called gene editing to delete three sets of genetic instructions to make them compatible (more on that later). The double-dad approach was slightly more complicated. It took a sperm, a male haploid embryonic stem cell, an egg that had all of its own genetic information removed and the deletion of seven genes to make it all work.

The reason we need to have sex is because our DNA -- our genetic code -- behaves differently depending on whether it comes from mum or dad, the study in Cell Stem Cell suggests. And without a female copy and a male copy our whole development gets thrown out of whack. It's called genomic imprinting with parts of the DNA in sperm and parts of the DNA in eggs getting different "stamps" that alter how they work. The bits of DNA carrying these stamps were the ones the researchers had to delete in order to make the baby mice viable.

An anonymous reader quotes a report from IEEE Spectrum: Over the past six months a small, publicly available genealogy database has become the go-to source for solving cold case crimes. The free online tool, called GEDmatch, is an ancestry service that allows people to submit their DNA data and search for relatives -- an open access version of AncestryDNA or 23andMe. Since April, investigators have used GEDmatch to identify victims, killers, and missing persons all over the U.S. in at least 19 cases, many of them decades old, according to authors of a report published today in Science. The authors predict that in the near future, as genetic genealogy reports gain in popularity, such tools could be used to find nearly any individual in the U.S. of European descent.

GEDmatch holds the genetic data of only about a million people. But cold case investigators have been exploiting the database using a genomic analysis technique called long-range familial search. The technique allows researchers to match an individual's DNA to distant relatives, such as third cousins. Chances are, one of those relatives will have used a genetic genealogy service. More than 17 million people have participated in these services -- a number that has grown rapidly over the last two years. AncestryDNA and 23andMe hold most of those customers. A genetic match to a distant relative can fairly quickly lead investigators to the person of interest. In a highly publicized case, GEDmatch was used earlier this year to identify the "Golden State Killer," a serial rapist and murderer who terrorized California in the 1970s and 1980s, but was never caught. In April, investigators were able to use a genealogy database to narrow down DNA data from crime scenes and identify the "Golden State Killer," a serial rapist and murderer who terrorized California in the 1970s and 1980s.

Researchers at the University of Washington have developed 3D printed assistive technology that can track and store their use -- without using batteries or electronics. From a blog post on University of Washington: Cheap and easily customizable, 3D printed devices are perfect for assistive technology, like prosthetics or "smart" pill bottles that can help patients remember to take their daily medications. But these plastic parts don't have electronics, which means they can't monitor how patients are using them. Now engineers at the University of Washington have developed 3D printed devices that can track and store their own use -- without using batteries or electronics. Instead, this system uses a method called backscatter, through which a device can share information by reflecting signals that have been transmitted to it with an antenna.

"We're interested in making accessible assistive technology with 3D printing, but we have no easy way to know how people are using it," said co-author Jennifer Mankoff, a professor in the UW's Paul G. Allen School of Computer Science & Engineering. "Could we come up with a circuitless solution that could be printed on consumer-grade, off-the-shelf printers and allow the device itself to collect information? That's what we showed was possible in this paper." The UW team will present its findings next week at the ACM Symposium on User Interface Software and Technology in Berlin.

Two astronomers have asked a question for the ages: Can moons have moons? The delightful, if theoretical, answer is: Yes -- yes, they can. Sarah Laskow, writing for Atlas Obscura: As Gizmodo reports, this particular scientific inquiry began with a question from Juna Kollmeier's son. Kollemeier, who works at the Observatories of the Carnegie Institution of Washington, recruited Sean Raymond, of the University of Bordeaux, to help her answer the question. In a paper posted on arXiv [PDF], they lay out their case that moons can have moons. The conditions have to be right -- the primary moon has to be big enough and far away enough from the planet it's orbiting for the smaller, secondary moon to survive. But, even given these caveats, they found that moons in our very own solar system could theoretically have their own smaller moons. Two of Saturn's moons and one of Jupiter's are candidates. So is our favorite moon -- the Earth's moon.

[...] One of the great challenges of talking about recursive places is deciding what call them. The prefix "sub-" can do a lot of work here: We can islands within islands "subislands," and in the arXiv paper, Kollmeier and Raymond call a moon's moon a "submoon." But there are other options. New Scientist notes that "moonmoon" has been put forth as a name for a moon's moon. For those of us who are less than fluent in meme culture: This is a reference to Moon Moon, sometimes described as the internet's derpiest wolf. Moon Moon was born in 2013, from a werewolf name generator, and soon started frolicking across Tumblr and all other places memes can be found.

Huge reductions in meat-eating are essential to avoid dangerous climate change, according to the most comprehensive analysis yet of the food system's impact on the environment. From a report: In western countries, beef consumption needs to fall by 90% and be replaced by five times more beans and pulses. The research [PDF] also finds that enormous changes to farming are needed to avoid destroying the planet's ability to feed the 10 billion people expected to be on the planet in a few decades. Food production already causes great damage to the environment, via greenhouse gases from livestock, deforestation and water shortages from farming, and vast ocean dead zones from agricultural pollution. But without action, its impact will get far worse as the world population rises by 2.3 billion people by 2050 and global income triples, enabling more people to eat meat-rich western diets.

The U.S. Air Force on Wednesday awarded funds to three rocket companies to help them complete development of their boosters. The three winners include:

United Launch Services: $967,000,000 for the development of the Vulcan Centaur launch system.
Northrop Grumman: $791,601,015 for development of the Omega launch system
Blue Origin: $500,000,000 for the development of the New Glenn launch system

The obvious company missing from the list is SpaceX, which did not win an award. Aerojet Rocketdyne also failed to win an award since it "does not appear to have a customer for its AR1 rocket engine, which the military initially supported," Ars Technica reports. From the report: These are hugely consequential awards for the rocket companies. Essentially the U.S. Air Force, which launches more complex, heavy payloads than any other entity in the world, believes these boosters will have a significant role to play in those missions during the next decade. And when the military has confidence in your vehicle, commercial satellite contracts are more likely to follow as well. After speaking with a couple of aerospace sources, Ars has a few theories as to why SpaceX didn't win an award: For one, SpaceX has already built and flown a rocket that can reach all of the Air Force's reference orbits -- the Falcon Heavy. Moreover, the Falcon Heavy is already certified for the Air Force and has won contracts. Air Force officials may also feel that, through NASA contracts for commercial cargo and crew, the government already facilitated development of the Falcon Heavy -- which uses three Falcon 9 rocket cores. It also depends upon what SpaceX bid for. The government would have been more inclined to fund development of an advanced upper stage for the Falcon Heavy or vertical integration facilities. But it seems like the military would not have been as interested in the Big Falcon Rocket, which is more booster than it deems necessary at this time. So if SpaceX bid the BFR, that is one possible explanation for no award.