Penguins can sniff out relatives

Penguins can be able to smell some feathery, waddling whiff of kinship on others of their kind.

In some sniff tests, Humboldt penguins (Spheniscus humboldti) in the Brookfield Zoo outside Chicago could discriminate between the odor of birds they knew and birds they weren’t familiar with, says Jill Mateo of the University of Chicago. More intriguingly, the birds also showed evidence of an ability to distinguish between the scents of relatives and nonrelatives even if they weren’t personally familiar with the scent owners, Mateo and her colleagues report September 21 in PLoS ONE.

The ability to recognize kin by smell has shown up in many other kinds of animals, including mammals, amphibians and fish. Although the new study is limited by its small size, it could be the first to show odor-based kinship recognition among birds.

New evidence that a sense of smell may be important in birds also makes the study intriguing. For decades, scientists thought that most species of birds responded minimally, if at all, to odor cues. In recent years, though, researchers have uncovered more and more evidence for functionally significant sniffing, such as the odor detection of food out in the open ocean by blue petrels and some other tubenose seabirds.

Odor-based kin recognition would make sense for colony-dwelling birds with lifetime monogamy such as the Humboldt penguins, which return to the same rookeries where they hatched in search of mating prospects. Birds hatched in different years by same parents could easily meet, Mateo says. “If familiarity is the only mechanism available to them, they might say, ‘Hey, I’m not related to you. Let’s have sex.” So a sniff test for kinship could come in handy.

To test the idea, Mateo’s team set up tests of odor discrimination for zoo penguins known to have had significant past contact with each other or not. Oily glandular secretions that the penguins use to preen their feathers provided the odors, and researchers smeared samples onto plastic dog kennels. Birds were allowed a short session of exploring an observation room with a pair of the plastic kennels, each newly perfumed with a different bird’s preen secretion.

Initially, researchers tested the birds’ ability to discriminate scents by comparing kennels scented with a familiar, nonrelated bird with that of an unrelated stranger. The birds spent about six times as long inside the familiar-smelling kennels.

Then researchers added kinship to the mix. In a test of 12 penguins, birds spent more than twice as long inside kennels scented with unfamiliar, unrelated birds than in kennels smelling of unfamiliar kin, the researchers noted.

Also, birds were twice as fast to toddle over and investigate the novel smell of unrelated strangers than when taking a closer sniff of unfamiliar kin. And nine of the 12 penguins entered that unrelated stranger’s kennel first, although neither of these results were as statistically convincing as the time the birds spent inside.

Working with a small colony of 22 birds and no more than 12 penguins for any given test, Mateo acknowledges that some results indicate only trends and more work is needed.

“It’s a very intriguing and promising start,” says avian behavioral ecologist Julie Hagelin of the University of Alaska Fairbanks, who studies chemical communication in birds.

Gabrielle Nevitt of the University of California, Davis, who works on bird olfaction, would like to know more about just what the penguins might have been detecting. “There is currently very little evidence to suggest that volatile signatures associated with preen gland secretion represent necessarily a 'genetic' signature of odor,” she says.

Other laboratories are investigating kin recognition by looking at underlying mechanisms, either at the genetic or biochemical level, Nevitt says

Source:  http://www.sciencenews.org

How Human Reached Asia

DNA extracted from a 40,000-year-old pinky bone and a 100-year-old lock of hair has provided glimpses of two Stone Age human migrations to Asia, including an early foray marked by interbreeding between ancient people and some mysterious, well-traveled members of the human evolutionary family.
Denisovans, an ancient humanlike population previously identified via nuclear DNA taken from a finger bone excavated in Siberia’s Denisova Cave, contributed a small portion of genes to living New Guineans, Australian aborigines, two aboriginal groups in the Philippines and populations on several nearby islands, say geneticist David Reich of Harvard Medical School in Boston and his colleagues.

Earlier analyses of modern human mitochondrial DNA, which is maternally inherited, had suggested that a single wave of humans took a southern coastal route from Africa to Asia around 65,000 years ago. Patterns of nuclear DNA alterations in an ancient Denisovan and in living groups instead point to at least two Stone Age human migrations into Asia, Reich’s team reports in a paper published online September 22 in the American Journal of Human Genetics.
A one-two punch of human migrations into Asia, including early interbreeding with the mysterious Denisovans, also emerges from an inspection of an Australian aboriginal man’s DNA, led by geneticist Morten Rasmussen of the Natural History Museum of Denmark in Copenhagen. Those results appear in a paper published online September 22 in Science.
Both new reports advance the idea that, after leaving Africa, modern humans interacted with a greater number of humanlike groups than are documented in the fossil record, remarks anthropologist John Hawks of the University of Wisconsin–Madison. Now that scientists can isolate ancient DNA from nondescript bits of bone, “we’re discovering lost peoples whose existence we never suspected,” Hawks says.

Several Chinese sites have yielded hominid fossils that may come from Denisovans, says anthropologist Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. These fossils date to between 200,000 and 100,000 years ago and don’t appear to him to belong to Homo sapiens orHomo erectus, a possible direct ancestor of modern humans.

“Denisovan genetic material in New Guinea, Melanesia and Australia implies that this ancient group peopled a territory much broader than the southern part of Siberia where it was first identified,” Hublin says.
An initial human spread into Asia included ancestors of groups now living in eastern Oceania, some of whom interbred with Denisovans, Reich’s group concludes. Earlier evidence from the same team indicated that New Guineans and residents of neighboring Bougainville Island inherited 4 to 6 percent of their DNA from Denisovans, a sister group of Neandertals (SN: 1/15/11, p. 10). A second migratory wave brought ancestors of present-day East Asians and Indonesians, who didn’t dally with Denisovans.

Intriguingly, H. sapiens interbred with Neandertals upon reaching western Asia (SN: 6/5/10, p. 5) and with Denisovans upon reaching southeastern Asia, says molecular anthropologist Mark Stoneking of the Max Planck Institute for Evolutionary Anthropology, a study coauthor with Reich. In both instances modern human populations contained relatively few individuals, creating pressure to mate with outsiders in order to expand group numbers, Stoneking speculates.

Reich’s team compared Denisovan DNA to that of 260 people from 33 Asian populations. Denisovan genetic signatures are easily recognizable in the DNA of people today, Reich says.
Australian aborigines share as much DNA with Denisovans as do New Guineans, the researchers say. Several other island populations in eastern Oceania display lesser amounts of Denisovan genetic material. Groups in Indonesia and mainland Asia possess no Denisovan genetic remnants.
All non-Africans possess roughly the same amount of Neandertal DNA, about 1 percent to 4 percent. That’s consistent with a single human migration out of Africa about 65,000 years ago, followed by interbreeding with Neandertals in western Asia, Reich says. A trek to Southeast Asia then must have occurred. Common ancestors of New Guineans and Australian aborigines mated with Denisovans there at least 44,000 years ago, before journeying to their current homelands, the scientists estimate. Ancestors of East Asians and Indonesians arrived in a later migration.

Further genetic evidence that ancient people reached Asia in at least two waves — the first of which interbred with Denisovans — comes from a preserved lock of hair that an Australian aboriginal man donated to scientists about 100 years ago. Rasmussen’s group compared the man’s DNA, and that of three Chinese individuals, to genetic sequences of living Africans and Europeans, as well as to Denisovan DNA.

Australian aborigines trace their ancestry to a human migration into Southeast Asia sometime between 75,000 and 62,000 years ago, the investigators estimate. Denisovans interbred to a slightly lesser extent with ancestors of Australian aborigines than with ancestors of New Guineans, they find.
A second round of human arrivals gave rise to East Asians starting between 38,000 and 25,000 years ago, Rasmussen and his colleagues propose. As in Reich’s study, most current Asian populations studied by Rasmussen’s team lack Denisovan DNA.

By the time of the second human migration into Asia, early arrivers had displaced or replaced Denisovans in Southeast Asia, Hublin suggests.
Further investigations of the genetic history of Australian aborigines will reveal much about human evolution, Hawks predicts. Unlike most people today, these hardy foragers have DNA uncluttered by the relatively recent evolutionary legacy of agricultural lifestyles.

Source:  http://www.sciencenews.org

Cern Claims Neutrons Travel Faster Than The Speed Of Light

Scientists have said they have clocked subatomic particles traveling faster than light – a feat that, if true, would break Albert Einstein’s special theory of relativity and undermine laws that underpin physics.

The Cern team says a neutrino beam fired from a particle accelerator near Geneva to a lab 730km (454 miles) away in Italy traveled 60 nanoseconds faster than the speed of light.

They calculated the margin of error at just ten nanoseconds, making the difference statistically significant.

The researchers have asked others to independently verify the data before claiming the discovery.

‘We have not found any instrumental effect that could explain the result of the measurement,’ said Antonio Ereditato, a physicist at the University of Bern, Switzerland, who was involved in the experiment.

But other experts have remained cautious.

‘This would be such a sensational discovery, if it were true, that one has to treat it extremely carefully,’ said physicist John Ellis.

‘The feeling that most people have is this can’t be right, this can’t be real,’ said James Gillies, a spokesman for Cern, which also hosts the massive Large Hadron Collider which did not take part in the experiment.

Einstein insisted nothing could travel faster than light – 300,000km (186,282 miles) a second.

He reasoned something that travels faster than light would, in theory, arrive before it left.

Special relativity, which helps explain everything from black holes to the Big Bang theory about the origins of the universe, underlies ‘pretty much everything in modern physics,’ added Mr Ellis. ‘It has worked perfectly up until now.’

He also warned that the neutrino researchers would also have to explain why similar results weren’t detected before, such as when stars exploded.

There was no doubt that the use of natural course. Alvaro de Rujula, where the neutron beam of the CERN, Geneva, previously undetected by the European Organization for Nuclear Research, a theoretical physicist, human error to blame for reading. When you open the doors to the wild, and it is great. De Rujula the average person, "as a theory, back to the time of travel and the world before they kill her mother." Said However, science fiction stories Ereditato intimidate his team and kept them at night.  

"We are continuing the investigation, and we will wait patiently for"

The AP said. "Everyone can do. This is a dream" Then, "I'll tell you my dreams." He said 

Source: www.eutimes.net