Study suggests Neanderthals not the only one humans bred with

May 13, 2010 By Leave a Comment

London, May 13 (ANI): A new study has found that Neanderthals were not the only other Homo species early Homo sapiens mixed with.

João Zilhão at the University of Bristol, UK, suggests H. sapiens migrated from Africa to meet and interbred with other Homo species that have now become extinct.

Swedish biologist Svante Svante Pääbo”s team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany have found the first definitive evidence of interbreeding.

They reported last week that the genome of humans today is roughly 1 to 4 per cent Neanderthal.

The fact that all non-Africans have this percentage, suggests that H. sapiens and Neanderthals interbred sometime between 100,000 and 45,000 years ago, after the first humans left Africa but before they split into regional populations.

Another genetic study confirmed the suggestion made by Svante Pääbo”s team.

Jeffrey Long at the University of New Mexico in Albuquerque presented results from nearly 100 modern human populations at a meeting of the American Association for Physical Anthropologists in April.

The experts found proof that Eurasians became genetically diverse by breeding with other Homo species after they left Africa, reports New Scientist.

Also, they observed a spike in genetic diversity in Indo-Pacific peoples, dating to around 40,000 years ago. Again, it”s unlikely the diversity came from H. sapiens interbred with Neanderthals, as the latter never travelled that far south.

Meanwhile, Zilhão”s team in Portugal discovered the 25,000-year-old bones of a child they are convinced is a human-Neanderthal hybrid. Zilhão says fossils from Romania and the Czech Republic also bear Neanderthal features, though others dispute this.

Moreover, decorative artefacts characteristic of humans have cropped up at Neanderthal sites, dated to around the time of contact with humans in Africa and the Middle East. Further east, 40,000-year-old human bones from a cave near Beijing, China, have features that recall other Homo species, says Erik Trinkaus of Washington University in St Louis, Missouri.

In March, Pääbo”s team reported the discovery of DNA from a hominin that is probably neither human nor Neanderthal that lived 50,000 to 30,000 years ago in a cave in southern Siberia. They dubbed the creature X-woman, and sequencing machines are already decoding its genome, says Pääbo”s colleague Ed Green of the University of California, Santa Cruz.

Green does not wish to dismiss the idea that X-woman or its kind have bred with humans. (ANI)

Filed Under: International News Tagged With: , , , , , , , , , , , , , , , , , , ,

Genetic study sheds light on chronic pain

May 7, 2010 By Leave a Comment

Washington, May 7 (ANI): Chronic pain, which often occurs without an apparent cause, may be caused by the inadvertent reprogramming of more than 2,000 genes in the peripheral nervous system, suggests new research.

Mayo Clinic researchers think that the finding could ultimately lead to ‘transcription therapy’, which would employ drugs that kill pain by correcting the activity of specific genes.

The researchers focused on nerve cells suspected to be involved in pain: dorsal root ganglion neurons of the peripheral nervous system in rodent models. They performed high-throughput sequencing of hundreds of millions of mRNA molecules, the messengers of gene activity.

Powerful computer science was required to sort through the many pieces of information (50 base-pair long mRNA sequence “reads”) assembling the complicated genomic puzzle.

The resulting picture revealed a number of surprises, among them 10,464 novel exons (sections of the genome involved in creating proteins) and some 400 gene candidates described for the first time in the study.

Furthermore, detailed building plans for thousands of spliced mRNA were mapped.

“Using this new approach offers greater sensitivity, dynamic range and more efficient unbiased genetic mapping compared to the previous microarray-based methods and may be an efficient new approach to a wide array of problems in neuroscience research,” says Andreas Beutler, Mayo Clinic oncologist and co-author on the study.

The findings appear in the current issue of the journal Genome Research. (ANI)

Filed Under: International News Tagged With: , , , , , , , , , , , , , , , , , , ,

Smoking may be in your genes

April 26, 2010 By Leave a Comment

London, April 26 (ANI): For some smokers, quitting the habit could be especially difficult because their dependence may be explained in part by genetics, says a new study.

Scientists have identified genetic variants associated with key smoking behaviors that have a significant impact on health.

Helena Furberg, and Patrick Sullivan, from University of North Carolina at Chapel Hill School of Medicine, led the largest genetic study of smoking, called the Tobacco and Genetics Consortium (TAG), collaborating with scientists from 16 large genetic studies worldwide.

They compared the DNA marker profiles between smokers and non-smokers to examine whether genetic variants affect whether people start to smoke.

They also compared the DNA among smokers to see if genetic variants affected the number of cigarettes smoked per day, the age when people began to smoke and whether smokers were able to quit.

The team found that three genetic regions were associated with the number of cigarettes smoked per day, one region was associated with smoking initiation and one variant was associated with smoking cessation.

The variants on chromosome 15 that were associated with heavy smoking lie within a region that contains nicotinic receptor genes, which other scientists have previously associated with nicotine dependence and lung cancer.

“We hope that this work will allow researchers from multiple disciplines to develop a better understanding of the genetics of addiction and evaluate how drug-gene interactions could be used to create and tailor therapies to improve the rates of smoking cessation,” said Furberg.

“More work needs to be done before these findings can be used to treat smokers who wish to quit. At this time, testing for these variants will not tell you anything meaningful about your risk of smoking or nicotine dependence. Of course, all smokers should be encouraged to quit regardless of their genetic make-up,” she added.

The study has been paper in the journal Nature Genetics. (ANI)

Filed Under: International News Tagged With: , , , , , , , , , , , , , , , , , , ,

Worker bees engage in ‘reproductive class war’ with queen

September 10, 2009 By Leave a Comment

Washington, Sep 10 (ANI): All is not hunky-dory among the members of bee colonies, which are known for their cooperation. A new research has shown a conflict for reproduction between worker bees and their Queens, leading some workers to selfishly exploit the colony for their own needs.

The study focused on Melipona scutellaris, a Brazilian species of highly social stingless bees, found throughout the Atlantic rainforest. Colonies contain around 1,500 workers and are headed by one single-mated Queen.

Researchers led by Denise Alves, carried out a genetic study of nearly 600 males from 45 colonies to discover the parentage of the worker population.

Their results showed that 22.89 percent of Melipona scutellaris males are sons of the workers rather than the Queen, which demonstrated an on-going conflict for reproduction.

“Surprisingly our results show that over 80% of the worker’s sons had genotypes that were incompatible with them being the sons of the present queen. This demonstrates, for the first time, how workers continue this conflict by reproductively parasitizing the next-generation of the workforce for their own selfish benefit,” said Alves.

Worker bees are generally unable to mate, but are capable of laying unfertilised eggs which can develop into male offspring.

To assure dominance over reproduction the Queen often selectively eats any worker laid eggs. In some species other workers may eat the eggs of fellow workers in what is known as ‘worker policing’.

But despite these barriers there is much to gain for worker bees producing their own offspring, however the benefit is entirely for the individual and can be costly for the colony overall.

The team found that workers who reproduce could live as much as three times longer, meaning that reproducing workers have a life expectancy almost matching the Queen herself.

This added life expectancy could be because workers who reproduce do not usually carry out risky tasks such as foraging.

However as worker bees who are reproducing are not working, an increase in individual workers who reproduce puts the collective production of the colony in jeopardy, hence a queen-worker conflict over the production of males ensues.

To demonstrate this conflict the team studied the genotypes of worker and queen bees from 45 colonies.

If a male carried a genotype not present in either the mother queen or her mate, then it was clear the male was either the son of an invading bee or of a worker who superseded the Queen.

The team estimates 77.11 percent of the males were the queen’s sons, 4.34 percent were the sons of the workers derived from the current queen and 18.54 percent were the sons of workers derived from a previous, superseded queen.

“These results are the first explicit demonstration that conflict over male parentage in insect societies is not just played out between the queen and workers, but shows that the conflict may also spill over from one generation of workers to the other,” concluded Alves.

The study has been published in Molecular Ecology. (ANI)

Filed Under: Science News Tagged With: , , , , , , , , , , , , , , , , , , , ,

Six facts about the female orgasm revealed by modern science

May 29, 2009 By Leave a Comment

London, May 29 (ANI): While female orgasm has been the subject of so many myths and folk beliefs, scientists are trying their best to know more about the mystery behind the phenomenon.

And now, after some intense field research, a team of experts have uncovered six facts about the female orgasm, as revealed by modern science, reports New Scientist magazine.

The six facts are as follows:

The G spot is real

The G spot is a small region in the vagina that, if stimulated, can produce wildly intense orgasms – or so goes the popular claim. But, since decades, strong evidence for the region’s existence was harder to find than the spot itself.

However, in 2008, an Italian research team solved the mystery after they found anatomical differences between women who could have G-spot orgasms and women who couldn’t. And since then, researchers have since begun teaching women with G spots how to put them to use.

The brain switches off

It’s folk wisdom that people can’t think straight when they have sex on their minds, and a brain scanning study showed that many areas of women’s brains were deactivated during orgasm, including those involved in emotion.

Many women can’t have orgasms

According to a 1999 survey, around 43 per cent of women in the US have some sort of problem with their sex lives.

Female sexual dysfunction (FSD) is so common that the very idea that it is a medical disorder has come under attack and thus efforts to develop drugs to treat it are underway.

Genes affect orgasm frequency

According to the first genetic study of the female orgasm, up to 45 per cent of the variation in women’s ability to have them could be down to genes.

Many women never have orgasms during intercourse, and some also cannot have them through masturbation. Some of this may be down to external factors like upbringing, but the study showed the genetic factor is significant.

Technology can help

Perhaps the most extreme solution for sexual dysfunction among women is the so-called “orgasmatron”-an implant inserted into the spinal cord, which stimulates the user when switched on via a remote control.

Despite an initial struggle to find subjects for clinical testing, the device is now in development.

Some mystery remains

The female orgasm is a puzzle for evolutionary biologists. It is unclear why women should have orgasms at all, and it is particularly baffling that so many women should be unable to have orgasms during penetrative sex, but able to have them by masturbation.

According to researcher Elisabeth Lloyd, this implies that female orgasms are an evolutionary accident. Like male nipples, they persist simply because there is no good reason to get rid of them. (ANI)

Filed Under: Science News Tagged With: , , , , , , , , , , , , , , , , , , ,

Indian-origin researcher unveils gene behind autoimmune disease lupus

March 30, 2009 By Leave a Comment

Washington, Mar 30 (ANI): A gene linked to the autoimmune disease lupus, and its location on the X chromosome can explain why females are 10 times more susceptible to the disease than males, according to a new study.

Researchers at UT Southwestern Medical Center identified the gene called IRAK1 as part of an international human genetic study.

Systemic lupus erythematosus, or lupus for short, causes a wide range of symptoms such as rashes, fever or fatigue that make it difficult to diagnose.

Dr. Chandra Mohan, professor of internal medicine and senior author of the study, said that identifying IRAK1 as a disease gene may also have therapeutic implications.

“Our work also shows that blocking IRAK1 action shuts down lupus in an animal model. Though many genes may be involved in lupus, we only have very limited information on them,” he said.

He also said that locating IRAK1 on the X chromosome also represents a breakthrough in explaining why lupus seems to be sex-linked.

He pointed out that researchers have for long focused on hormonal differences between males and females as a cause of the gender difference.

“This first demonstration of an X chromosome gene as a disease susceptibility factor in human lupus raises the possibility that the gender difference in rates may in part be attributed to sex chromosome genes,” he said.

The study involved 759 people who had developed lupus in their childhood, 5,337 patients who had developed it as adults, and 5,317 healthy controls.

Each group comprised four ethnicities: European-Americans, African-Americans, Asian-Americans and Hispanic-Americans.

Although researchers had found an association between lupus and IRAK1 in previous genetic studies, they failed to find a definite link.

For the current study, the researchers studied five variations of the IRAK1 gene in the subjects, and found that three of the five variants were common in people with either childhood-onset or adult-onset lupus.

For further testing of the link, they took mice of a strain that normally were prone to developing lupus, and engineered them to lack the IRAK1 gene.

It was found that when IRAK1 was absent, the animals lacked symptoms associated with lupus, including kidney malfunction, production of autoimmune antibodies and activation of white blood cells.

“The extensive involvement of IRAK1 in the regulation of the immune response renders its association with lupus a prime candidate for careful genetic and functional analysis,” said Mohan.

Future research will investigate the role that X-linked genes, versus hormonal differences, play in the gender susceptibility rates of lupus.

The study appeared online in the Proceedings of the National Academy of Sciences. (ANI)

Filed Under: Science News Tagged With: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Species of Australian lizards much more than previously thought

March 5, 2009 By Leave a Comment

Washington, March 5 (ANI): A genetic study, conducted by a University of Adelaide researcher, has discovered that there are many more species of Australian lizards than previously thought, raising new questions about conservation and management of Australia’s native reptiles.

The study, done by Paul Oliver, a PhD student from the University’s School of Earth and Environmental Sciences, focused on the Australian gecko genus Diplodactylus and found more than twice the recognised number of gecko species, from 13 species to 29.

“Many of these species are externally very similar, leading to previous severe underestimation of true species diversity,” said Oliver.

According to Oliver, “One of the major problems for biodiversity conservation and management is that many species remain undocumented. This problem is widely acknowledged to be dire among invertebrates and in developing countries.”

“But, in this group of vertebrates in a developed nation, which we thought we knew reasonably well, we found more than half the species were unrecognized,” he added.

Oliver said that this has great significance for conservation.

For instance, what was thought to be a single very widespread species of gecko has turned out to be eight or nine separate species with much narrower, more restricted habitats and possibly much more vulnerable to environmental change, he said.

“This completely changes how we look at conservation management of these species. Even at just the basic inventory level, this shows that there is a lot of work still to be done,” he said.

“Vertebrate taxonomy clearly remains far from complete with many species still to be discovered. This will require detailed genetic and morphological work, using integrated data from multiple sources.

It will require considerable effort and expense but with potentially rich returns,” he added. (ANI)

Filed Under: Science News Tagged With: , , , , , , , , , , , , , , , , , , ,

How little ‘nano-machines’ inside the body operate

December 20, 2008 By Leave a Comment

Washington, December 20 (ANI): A team of researchers from the university of Montreal and the University of Chicago claims to have made a discovery that can improve scientists’ understanding of ion channels, which are akin to little ‘nano-machines’ or ‘nano-valves’ inside the body.

The discovery attains significance as ion channels, when malfunction, can cause genetic illnesses that attack muscles, the central nervous system, and the heart.

Reporting their work in the Proceedings of the National Academy of Sciences (PNAS), the researchers said that they had developed a new method to detect the movement of single proteins that control the ion exchange between the cells and their environment.

According to background information in the research article, these proteins open and close much like an iris in a camera, and thereby control the movement of ions between the cells and their environment, which allows the transmission of electrical signals along our nerve cells.

The article further states that these valves are about a million times smaller than the pupil of a human eye.

The researchers insist that their new technique can help measure one single ion channel at the time, and investigate how different parts inside the ion channels communicate.

“Our discovery will help advance the basic understanding of ion channels. These membrane proteins mark a major drug target, since they play a central role in the entire body and mutations in their genes cause many severe genetic illnesses,” says Rikard Blunck, a professor from the University of Montreal’s Department of Physics, and one of the lead researchers.

For their study, the researchers investigated potassium channels built out of four identical subunits, which form a pore through the membrane that can open and close in order to allow or block ion conduction.

Their study solved a long debate over whether the four subunits of a K+ channel function independently or in a concerted action.

With a view to determining that question, the researchers developed a fluorescence spectroscopy technique that allowed distinguishing between the subunits so that one could follow the movement of each of the four subunits, information that was lost in previous measurements.

The team observed that the four molecules act together, which explains why no intermediate steps are found in the electrical current measured in electrophysiological experiments. (ANI)

Filed Under: Science News Tagged With: , , , , , , , , , , , , , , , , , , , , , , , , , , , ,