Researchers have discovered the first brain regulatory gene that shows clear evidence of evolution from lower primates to humans. They said the evolution of humans might well have depended in part on hyperactivation of the gene, called prodynorphin (PDYN), that plays critical roles in regulating perception, behavior and memory.
According to brightsurf.com, they reported that, compared to lower primates, humans possess a distinctive variant in a regulatory segment of the prodynorphin gene, which is a precursor molecule for a range of regulatory proteins called “neuropeptides.“ This variant increases the amount of prodynorphin produced in the brain.
While the researchers do not understand the physiological implications of the activated PDYN gene in humans, they said their finding offers an important and intriguing piece of a puzzle of the mechanism by which humans evolved from lower primates.
They also said that the discovery of this first evolutionarily selected gene is likely only the beginning of a new pathway of exploring how the pressure of natural selection influenced evolution of other genes.
They also said their finding demonstrates how evolution can act more efficiently to alter the regulatory segments, or “promoters,“ that determine genes’ activity, rather than on the gene segment that determines the structure of the protein it produces.
Such regulatory alteration, they said, can more readily generate variability than the hit-or-miss mutations that alter protein structure and function.
Proteins constitute the molecular machinery of the cell, for example, catalyzing the multitude of chemical reactions in the cell.
DNA genes constitute the blueprints for such proteins, with the regulatory segments of these genes determining how actively the genes churn out proteins.
In their studies, the researchers analyzed the sequence structure of the PDYN promoter segment in humans and in seven species of non-human primates--chimpanzees, bonobos, gorillas, orangutans, baboons, pig-tailed macaques and rhesus monkeys.
They found significant mutational changes in the regulatory sequence leading to humans that indicated preservation due to positive evolutionary selection. They also found an “evolution-by-association,“ in which sequences near the regulatory segment showed greater mutational change--as if they were “dragged along“ with the evolving regulatory sequence.
In contrast, the researchers found that the DNA segment that coded for the PDYN protein itself--as well as other sites spread around the genome--showed evidence of “negative selection“ that would preserve their original structure.
The researchers also found evidence of evolutionary selection when they compared the regulatory sequences in people from different populations--including those from Cameroon, China, Ethiopia, India, Italy and Papua New Guinea.
Those analyses showed higher differences among the individual populations, but reduced variation within them. Such a pattern is a signature of evolutionary selection acting on the genetic sequence, said Wray.

Scientists at UCSF have determined that the quality of bone matrix, a key component of bone, is regulated by a molecule known as transforming growth factor beta, Eurekalert reported.
The finding, they say, suggests a possible target for preventing and treating bone fractures associated with aging and genetic diseases.
The study will be reported later this week in the Online Early Edition of Proceedings of the National Academy of Sciences (PNAS).
The ability of bone to resist damage depends on the mass, or quantity, of bone, its architecture and the quality of bone matrix, the mineralized material between cells.
Several molecular factors have been shown to regulate the mass and architecture of bone. So far, however, none have been shown to regulate bone matrix, which is responsible for bone elasticity and toughness.
There has been significant disagreement about whether the quality of bone matrix varies among individuals and, if it does, whether it could be altered for therapeutic reasons.
In any case, until now, scientists have lacked a strategy for measuring its quality and teasing out its impact, says senior study author Tamara Alliston, PhD, UCSF assistant adjunct professor of Cell and Tissue Biology.
In the current study, the team explored whether transforming growth factor beta (TGF-§) regulates the properties of bone matrix because there were hints that it might. TGF-§ is known to play a role in the development of osteoblasts, cells that produce bone matrix.
The researchers carried out their evaluation in five sets of mice genetically engineered to produce differing levels of TGF-§ signaling within osteoblasts, and, for comparison, in normal, or ’wild type’ mice. After the animals had been euthanized, the team utilized highly sensitive instruments developed in the materials sciences--atomic-force microscopy, x-ray tomography and micro-Raman spectroscopy--to measure the properties of bone matrix independent of bone mass and architecture. They also compared the bones’ resistance to fracture in a bending test.
The results were notable, according to Alliston. In animals genetically engineered to produce high levels of TGF-§, the measurements of bone matrix indicated increased susceptibility to fracture.
The matrix was less elastic, less hard and contained lower levels of the mineral calcium phosphate. In addition, the animals’ bones were less resistant to fracture in the bending test.
In contrast, in animals with low levels of TGF-§ the bone matrix was more elastic, harder, had higher mineral concentration and the bone overall had increased mass. In addition, the bones were more resistant to fracture in the bending test.
The bones studied included the femur, tibia and calvarial parietal bones.
The study suggests, she says, that TGF-§ could be targeted for clinical intervention in patients. “By decreasing TGF-§ signaling at the relevant site in the body, we may be able to improve the quality of bone to either prevent the damage that occurs in osteoarthritis and osteoporosis, or improve the quality and speed of bone repair following bone fracture, joint implantation, dental implants or bone grafting.

The burned-out stellar remnant is a faint companion of the brilliant blue-white Dog Star, Sirius, located in the winter constellation Canis Major.

An international team of astronomers has used the Hubble Space Telescope to isolate light from the white dwarf called Sirius B.
The burned-out stellar remnant is a faint companion of the brilliant blue-white Dog Star, Sirius, located in the winter constellation Canis Major, Science Daily reported.
It’s been a source of frustration for astronomers that the nearest white-dwarf to Earth was buried in the glow of the brightest star in our nighttime sky. But the European Space Agency/NASA telescope will now allow them to measure precisely the white dwarf’s mass based on how its intense gravitational field alters the wavelengths of light emitted by the star.
“Studying Sirius B has challenged astronomers for more than 140 years,“ said Martin Barstow of England’s University of Leicester, leader of the observing team.
“Only with Hubble have we at last been able to obtain the observations we need, uncontaminated by the light from Sirius, in order to measure its change in wavelengths.
“Accurately determining the masses of white dwarfs is fundamentally important to understanding stellar evolution,“ said Barstow.

By encoding information in the quantum states of subatomic particles, quantum computers have the potential to make the latest Pentium chip look as outmoded as the abacus. But before such a device can even begin to compete with its classical counterpart, we need to first find a way to scale-up individual quantum “bits“, Physicsweb.com reported.
Now, physicists in the US have made an important step towards this goal by creating an ion trap on a semiconductor chip. Such microscale traps could allow many qubits to be integrated in a workable quantum computer.
Classical computers store and process information as bits with one of two values: “0“ or “1“. But a quantum computer would exploit the ability of quantum particles to be in superpositions of two or more states at the same time. These “entangled“ states, in principle, allow a quantum computer to outperform a classical computer for certain tasks. One of the most exciting candidates for such a quantum bit or “qubit“ is a trapped ion, whose internal energy states can be manipulated using a laser.
The basic requirements for such a qubit have already been met, and very recently two groups set a new record by entangling up to eight calcium ions in a single trap. But a real quantum computer will require such trapping and manipulation to take place for millions of atoms.
Chris Monroe of the University of Michigan and colleagues at the University of Maryland have now made an ion trap from four alternating layers of aluminium-gallium-arsenide and gallium-arsenide grown on a substrate using molecular-beam epitaxy.
The team created a hole through the chip and fashioned a set of cantilevered electrodes over it using techniques routinely employed in fabricating microelectromchanical systems (MEMS). They then mounted the chip on a socket inside a vacuum, and introduced a gas of cadmium-111 atoms into the hole using a pulsed laser.

Physicists at nearly a dozen research institutions, including New York University, have discovered evidence for very high energy gamma rays emitting from the Milky Way, marking the highest energies ever detected from the galactic equator.
According to Eurekalert, their findings were obtained using the Milagro Gamma Ray Observatory, a new detector located near Los Alamos, N.M., that allows monitoring of the northern sky on a 24-hour, 7-day-per-week basis.
Gamma rays are considered by scientists to be the best probe of cosmic rays outside the solar neighborhood.
The research team, which includes nearly 40 physicists, reported that Milagro, positioned at an altitude of 8600 feet in the Jemez Mountains, detected a signal along the galactic equator region and interpreted it as arising from gamma rays with a median energy of 3.5 trillion electron-volts, or 3500 times the mass-energy of a proton.
Previous satellite experiments have seen gamma-ray emissions along the galactic equator reaching up to energies of only 30 billion electron-volts.
These emissions are understood to be produced by interactions of cosmic-ray particles with the abundant interstellar medium near the galactic equator.
Previously, some researchers had speculated that additional mechanisms were needed to explain the large number of particles observed at high energies.
However, the measurements by Milagro can be understood by assuming a cosmic ray energy spectrum near the galactic center similar to that in the solar system and the standard properties of particle interactions.

A team of theoretical and experimental physicists from Rice University is preparing a unique probe in hopes of “dialing in“ elusive quantum states called “quantum criticalities.“
According to Science Daily, the team is using nanotechnology to create a probe capable of trapping and tuning a single electron to create the rarified physical state in nearby magnetic electrodes.
The probe, a transistor thousands of times smaller than a living cell, is described in research published online this week by the Proceedings of the National Academy of Sciences.
“The traditional theory of metals, which has held sway for 50 years and has fostered terrific technological advances in computing and materials science, breaks down completely in matter that exists in a ’quantum critical state,’“ said Qimiao Si, professor of physics and astronomy at Rice and the lead theoretician on the project.
The term “quantum critical point“ refers to a phase transition. Just as water goes through a phase transition when it turns to ice or steam, all matter is subject to phase transitions due to fluctuations produced by the peculiar forces of quantum mechanics.
The probe proposed by Si and colleagues is based on a transistor with an active channel measuring just a few billionths of meter across. The transistor also uses a pair of electrodes made of ferromagnetic metal.
The researchers plan to trap a single electron in the active channel between the electrodes. Then, they will capitalize on a uniquely quantum effect--the tendency of a trapped electron to “tunnel,“ or wink out of existence in one place and appear in another--to establish a quantum critical state in the metallic electrodes that trap the tiny particle.
Elementary particles like electrons have an intrinsic angular momentum known as spin. The probe’s design will allow the physicists to confine an electron with its spin on one molecule inside the transistor.
In one quantum state, the tunneling effect causes the constrained electron spin to become “entangled“ with the spins of electrons in the nearby metal electrodes.
The magnetic nature of the electrodes also dictates the existence of a collective oscillation among the spins of electrons in the electrodes. These oscillations--known as “spin waves“--will interact with the magnetic moment of the constrained electron’s spin and try to break the entanglement.
The quantum critical point occurs when it is broken and the material transitions from one quantum phase to the next.
The effect is manifested in the unique way that the electrical conductance of the transistor depends on temperature and frequency.
Though nano in scale, the new probe serves as a realistic model system to elucidate physics that cannot be explained by the traditional theory of metals, including phenomena associated with bulk materials like rare-earth-based heavy fermion metals and copper-based high temperature superconductors.