Indian genetic study says women more upwardly mobile

Indian genetic study says women more upwardly mobile

Scientists say a genetic study in India suggests that it's easier for women than men to rise through the country's caste system.
It found that genetic material passed on by women was more commonly found in adjacent castes than similar material passed on by men.
The study , carried out at Andhra University and based on blood samples from three-hundred men, also found that the DNA of men from higher castes resembled that of people who entered India from the north-west.
This would appear to support the theory that it was they who set up the caste system formed by the ruling elite.

Gene 'helped create human brain'

Gene 'helped create human brain'

The human brain is highly evolvedScientists have identified a gene that appears to have played a key role in the development of the human brain.
They believe it is responsible for the expansion of an area of the brain called the cerebral cortex which controls abstract reasoning.
This is much bigger in humans than their closest relatives - and gives us our extraordinary brain power.
The research, by Howard Hughes Medical Institute, US, is published in the journal Human Molecular Genetics.
Lead researcher Dr Bruce Lahn said: "People have studied the evolution of the brain for a long time, but they have traditionally focused on the comparative anatomy and physiology of brain evolution.

PRIMATE SPECIES STUDIED
Man
Chimpanzee
Gorilla
Orangutan
Gibbon
Macaque
Owl monkey

"I would venture, however, that there really hasn't been any convincing evidence until now of any gene whose changes might have contributed to the evolution of the brain."
The Howard Hughes team focused on the particular gene, called ASPM, because mutations in its make-up are known to be linked to severe reductions in the size of the cerebral cortex in people who carry them.
They compared the make-up of the human form of the gene with that in six other primate species, each of which corresponds to a key stage in the evolutionary path of modern man.
They ranged from the chimpanzee, which is man's closest living relative, to the owl monkey, a relatively primitive creature analogous to an early stage of human evolution.
They found evidence that the make-up of the gene changed significantly between the species - and the higher up the evolutionary scale they went, the more changes they found.
The biggest difference was found between the human and chimpanzee forms of the gene - confirming that the recent phase of human evolution has been the most speedy and profound.

Man's closest living relativeBy contrast, when researchers looked at the make-up of the gene in more primitive animals such as cows, sheep, cats and dogs they found little evidence of significant changes between species.
This implies that the speed of change was much slower further down the evolutionary ladder.
Dr Lahn said: "The fact that we see this accelerated evolution of ASPM specifically in the primate lineage leading to humans, and not in these other mammals, makes a good case that the human lineage is special."
The next stage in the research will be pin down exactly how ASPM functions in the brain.
Research has suggested that the gene regulates the rate at which brain cells are produced in the cerebral cortex.

Research finds 'unique human DNA'

Research finds 'unique human DNA'

Something in our genes gives us a powerful brainScientists say they have discovered a gene sequence which appears to play a central role in giving humans their unique brain capacity.
The area, called HAR1, has undergone accelerated evolutionary change in humans and is active during a critical stage in brain development.
The researchers compared genes from humans, chimpanzees and other animals to try to see which set man apart.
The Nature study was led by the University of California, Santa Cruz.

Something caused our brains to evolve to be much larger and have more functions than the brains of other mammals
Dr David Haussler

The researchers say they have yet to determine the precise function of the gene।
But they say the evidence suggests it may play a role in the development of the cerebral cortex - and may help explain the dramatic expansion of this part of the brain during human evolution.
They used a sophisticated computer analysis technique to compare genes from various species and pinpoint those which have undergone accelerated evolutionary changes in humans.
This highlighted the HAR1 region of the human genome.
Specialised nerve cells
The researchers examined this area more closely in the lab to pin down its structure, the tissues in which it is active, and to try to better understand its function.
They found HAR1 was part of two overlapping genes, of which one - HAR1F - was active in special nerve cells called Cajal-Retzius neurons.
These cells appear early in embryonic development and play a critical role in the formation of the layered structure of the human cerebral cortex.
Cajal-Retzius neurons release a protein called reelin that guides the growth of neurons and the formation of connections among them.
HAR1F was found to be active at the same time as the reelin gene.
Lead researcher Dr David Haussler said: "We don't know what it does and we don't know if it interacts with reelin.
"But the evidence is very suggestive that this gene is important in the development of the cerebral cortex and that's exciting because the human cortex is three times as large as it was in our predecessors.
"Something caused our brains to evolve to be much larger and have more functions than the brains of other mammals."
The analysis showed that HAR1 is essentially the same in all mammals except humans. There were just two differences between the versions found in chickens and chimps.
However, there were 18 differences between the chimp version and the one found in humans - which scientists say is an incredible amount of change to take place in a few million years.
The researchers believe the key gene does not control the production of specific proteins as most genes do, but instead plays a role in modifying the function of other genes.
Professor Chris Ponting, of the University of Oxford, said this suggested that the rapid evolution of the human brain might be due to subtle fine-tuning of genetic function.
His colleague, Dr Gerton Lunter, said: "What is really interesting is that this is a special type of gene.
"It seems likely that it changes the way the brain is wired in some way."

High IQ link to being vegetarian

High IQ link to being vegetarian

Intelligent children are more likely to become vegetarians later in life, a study says.

Vegetariansim has been linked to better heart health.

A Southampton University team found those who were vegetarian by 30 had recorded five IQ points more on average at the age of 10.
Researchers said it could explain why people with higher IQ were healthier as a vegetarian diet was linked to lower heart disease and obesity rates.
The study of 8,179 was reported in the British Medical Journal.
Twenty years after the IQ tests were carried out in 1970, 366 of the participants said they were vegetarian - although more than 100 reported eating either fish or chicken.
Men who were vegetarian had an IQ score of 106, compared with 101 for non-vegetarians; while female vegetarians averaged 104, compared with 99 for non-vegetarians.

We've always known that vegetarianism is an intelligent, compassionate choice benefiting animals, people and the environment
Liz O'Neill, of The Vegetarian Society

There was no difference in IQ score between strict vegetarians and those who said they were vegetarian but who reported eating fish or chicken।
Researchers said the findings were partly related to better education and higher occupational social class, but it remained statistically significant after adjusting for these factors.
Vegetarians were more likely to be female, to be of higher occupational social class and to have higher academic or vocational qualifications than non-vegetarians.
However, these differences were not reflected in their annual income, which was similar to that of non-vegetarians.
Lead researcher Catharine Gale said: "The finding that children with greater intelligence are more likely to report being vegetarian as adults, together with the evidence on the potential benefits of a vegetarian diet on heart health, may help to explain why higher IQ in childhood or adolescence is linked with a reduced risk of coronary heart disease in adult life."
Intelligence
However, she added the link may be merely an example of many other lifestyle preferences that might be expected to vary with intelligence, such as choice of newspaper, but which may or may not have implications for health.
Liz O'Neill, of the Vegetarian Society, said: "We've always known that vegetarianism is an intelligent, compassionate choice benefiting animals, people and the environment.
"Now we've got the scientific evidence to prove it. Maybe that explains why many meat-reducers are keen to call themselves vegetarians when even they must know that vegetarians don't eat chicken, turkey or fish."
But Dr Frankie Phillips, of the British Dietetic Association, said: "It is like the chicken and the egg. Do people become vegetarian because they have a very high IQ or is it just that they tend to be more aware of health issues?"