Researchers at the University of California, Davis, have discovered a key tool that helps sperm and eggs develop exactly 23 chromosomes each. The work, which could lead to insights into fertility, spontaneous miscarriages, cancer and developmental disorders, is published April 13 in the journal Cell.

Healthy humans have 46 chromosomes, 23 from the sperm and 23 from the egg. An embryo with the wrong number of chromosomes is usually miscarried, or develops disorders such as Down syndrome, which is caused by an extra copy of chromosome 21.

During meiosis, the cell division process that creates sperm and eggs, matching chromosomes pair up and become connected by "crossing over" with each other, said Neil Hunter, a professor of microbiology at UC Davis and senior author of the new study.

These connections are essential for precise chromosome sorting and the formation of sperm and eggs with exactly the right numbers of chromosomes. Crossovers also play a fundamental role in evolution by allowing the chromosomes to swap chunks of DNA, introducing some variety into the next generation.

Each pair of chromosomes must contain at least one crossover. But there shouldn't be more than about two crossovers per pair, or the genome could be destabilized.

In their paper, Hunter and his colleagues describe a "missing tool" that explains how crossovers are regulated.

"There must be enzymes that ensure at least one crossover, but not too many," said Hunter, who is also a member of the UC Davis Comprehensive Cancer Center research program.

New analysis of 36-year-old data, resuscitated from printouts, shows that NASA found life on Mars, an international team of mathematicians and scientists conclude in a paper published this week. Further, NASA doesn't need a human expedition to Mars to nail down the claim, neuropharmacologist and biologist Joseph Miller, with the University of Southern California's Keck School of Medicine, told Discovery News.

"The ultimate proof is to take a video of a Martian bacteria. They should send a microscope - watch the bacteria move," Miller said. "On the basis of what we've done so far, I'd say I'm 99 percent sure there's life there," he added. Miller's confidence stems in part from a new study that reanalyzed results from a life-detection experiment conducted by NASA's Viking Mars robots in 1976.

Researchers crunched raw data collected during runs of the Labeled Release experiment, which looked for signs of microbial metabolism in soil samples scooped up and processed by the two Viking landers. General consensus of scientists has been that the experiment found geological, not biological, activity.

In 1937, after the rise of quantum mechanics, Ettore Majorana, an Italian theoretical physicist, realized that the new physics implied the existence of a novel type of particles, now called Majorana fermions. After a 75-year hunt, researchers have now spotted the first solid evidence of their existence. And their discovery could hold the key to finally creating workable quantum computers .

Prior to Majorana's work, Austrian physicist Erwin Schrödinger came up with an equation that describes how quantum particles behave and interact. Paul Dirac, an English physicist, tweaked that equation to apply it to fermions, such as electrons, moving at near-light speed. That work tied together quantum mechanics and Einstein's special theory of relativity. It also implied the existence of antimatter, where every particle has an antimatter counterpart - such as electrons and positrons - and that the two would annihilate each other if they ever met. Dirac's work suggested that some particles, such as photons, could serve as their own antiparticles. But fermions weren't thought to be among them. It was Majorana's manipulations of Dirac's equations that suggested the possible existence of a new type of fermion that could serve as its own antiparticle.

At the time, Majorana thought a type of neutrino, an electrically neutral particle with a tiny mass, might fit the bill for his proposed particle. And scientists continue to search for evidence that neutrinos are or are not their own antiparticles. But decades after Majorana's proposal, theoretical physicists realized that the coordinated motion of large numbers of electrons in electronic devices might mimic the behavior of Majorana fermions. These collective motions aren't elementary bits of matter the way electrons and neutrinos are. Rather, they are "quasiparticles." But they should behave much as would elementary particles of the same type. It is the signs of these quasiparticles that researchers led by physicist Leo Kouwenhoven and colleagues at Delft University of Technology report online today in Science.

The first human eggs grown from human stem cells could be fertilized with human sperm cells later this year, potentially revolutionizing fertility treatment for women. This could be one more step on the path toward reproduction sans human interaction - in this case, a potential parent wouldn't even need to donate her eggs. But it could also turn stem cells into an infinite loop, of egg cells into embryos into stem cells, and on and on, in a fractal-like repetition of reproduction.

In February, we heard about a study involving Japanese women whose reproductive stem cells were donated because they were undergoing gender reassignment surgery. Researchers at Massachusetts General Hospital were able to coax these ovarian stem cells into becoming immature human egg cells, which were then incubated in mice so they'd have the proper ovarian structures. Now these same scientists, working with a team at Edinburgh University, want to fertilize them.

After sperm implantation, the scientists would watch the blastocysts develop into embryos for two weeks - the legal limit - and determine if they're viable. Then these embryos would either be frozen or "allowed to perish," according to the Independent. The tests would validate the stem-cell-derived human eggs, more properly called oocytes, and serve as an early indicator of whether they could someday be used to eradicate infertility.

New scientific research raises the possibility that advanced versions of T. rex and other dinosaurs - monstrous creatures with the intelligence and cunning of humans - may be the life forms that evolved on other planets in the universe. "We would be better off not meeting them," concludes the study, which appears in the Journal of the American Chemical Society.

In the report, noted scientist Ronald Breslow, Ph.D., discusses the century-old mystery of why the building blocks of terrestrial amino acids (which make up proteins), sugars, and the genetic materials DNA and RNA exist mainly in one orientation or shape. There are two possible orientations, left and right, which mirror each other in the same way as hands. This is known as "chirality."

In order for life to arise, proteins, for instance, must contain only one chiral form of amino acids, left or right. With the exception of a few bacteria, amino acids in all life on Earth have the left-handed orientation. Most sugars have a right-handed orientation. How did that so-called homochirality, the predominance of one chiral form, happen?

In science fiction - like in Star Trek, for example - interstellar communication was never a problem; all you had to do was have Urhura open up hailing frequencies to Starfleet command. But in the real universe, communicating between star systems poses a dilemma with current radio technology.

There's also a very real problem today for operating spacecraft in that communications are impossible when a planetary body is blocking the signal. One of the more outlandish methods proposed for solving deep space communication problems has been to devise a technique using neutrinos. But now, it turns out, using neutrinos for communication might not be that crazy of an idea: communicating with neutrinos has, for the first time, been tested successfully.

Scientists of the MINERvA collaboration at the Fermi National Accelerator Laboratory successfully transmitted a message through 240 meters of rock using neutrinos. The team says their demonstration "illustrates the feasibility of using neutrino beams to provide a low-rate communications link, independent of any existing electromagnetic communications infrastructure."

The scientists used the a 170-ton MINERvA detector at Fermilab and a NuMI beam line, a powerful, pulsed accelerator beam to produce neutrinos. They were able to manipulate the pulsed beam and turn it - for a couple of hours - into a sort of "neutrino telegraph," according to R&D magazine.

There may be some frantic activity going on in the narrow, dusty disk surrounding a nearby star named Fomalhaut. Scientists have been trying to understand the makeup of the disk, and new observations by the Herschel Space Observatory reveals the disk may come from cometary collisions. But in order to create the amount of dust and debris seen around Fomalhaut, there would have to be collisions destroying thousands of icy comets every day.

"I was really surprised," said Bram Acke, who led a team on the Herschel observations. "To me this was an extremely large number."

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The chip achieves unprecedented accuracy by processing information from many different sensors.

Broadcom has just rolled out a chip for smart phones that promises to indicate location ultra-precisely, possibly within a few centimeters, vertically and horizontally, indoors and out.

The unprecedented accuracy of the Broadcom 4752 chip results from the sheer breadth of sensors from which it can process information. It can receive signals from global navigation satellites, cell-phone towers, and Wi-Fi hot spots, and also input from gyroscopes, accelerometers, step counters, and altimeters.

The variety of location data available to mobile-device makers means that in our increasingly radio-frequency-dense world, location services will continue to become more refined.

A team of California scientists have developed the world's first portable brain scanner, and it may soon be able to "read a person's mind," playing a major role in facilitating medical breakthroughs.

"This is very exciting for us because it allows us to have a window into the brain. We're building technology that will allow humanity to have access to the human brain for the first time," said the project's leader, Phillip Low.

KGTV reports that the device, created by San Diego-based NeuroVigil, and dubbed the iBrain, fits over a person's head and measures unique neurological patterns connected to specific thought processes.

Comet Garradd sails slowly past globular star cluster M92 in this stunning image from a skywatcher in California.

The comet approached M92 as it flew over the Hercules constellation. It passed within half a degree of M92 on the day the image was taken.
M92 is one of the brightest globular clusters in the sky, and can sometimes be seen with the naked eye from the northern hemisphere. It's located more than 27,000 light-years from Earth. (A light-year is the distance light travels in one year - about 6 trillion miles, or 10 trillion kilometers.)