Genetic study pushes back timeline for first significant human population expansion

This week in the advance access edition of the journal Molecular Biology and Evolution

2013-09-25

(Press-News.org) About 10,000 years ago, the Neolithic age ushered in one of the most dramatic periods of human cultural and technological transition, where independently, different world populations developed the domestication of plants and animals. The hunter-gatherers gave rise to herders and farmers. Changes to a more sedentary lifestyle and larger settlements are widely thought to have contributed to a worldwide human population explosion, from an estimated 4-6 million people to 60-70 million by 4,000 B.C.

Now, researchers Aimé, et al., have challenged this assumption using a large set of populations from diverse geographical regions (20 different genomic regions and mitochondrial DNA of individuals from 66 African and Eurasian populations), and compared their genetic results with archaeological findings. The dispersal and expansion of Neolithic culture from the Middle East has recently been associated with the distribution of human genetic markers.

They conclude that the first significant expansion of human populations appears to be much older than the emergence of farming and herding, dating back to the Paleolithic (60,000-80,000 years ago) rather than Neolithic age. Therefore, hunter-gatherer populations were able to thrive with cultural and social advances that allowed for the expansion. The authors also speculate that this Paleolithic human population expansion may be linked to the emergence of newer, more advanced hunting technologies or a rapid environmental change to dryer climates.

Finally, they also suggest that strong Paleolithic expansions may have favored the emergence of sedentary farming in some populations during the Neolithic. Indeed, the authors also demonstrate that the populations who adopted a sedentary farming lifestyle during the Neolithic had previously experienced the strongest Paleolithic expansions. Conversely, contemporary nomadic herder populations in Eurasia experienced moderate Paleolithic expansions, and no expansions were detected for nomadic hunter-gatherers in Africa. "Human populations could have started to increase in Paleolithic times, and strong Paleolithic expansions in some populations may have ultimately favored their shift toward agriculture during the Neolithic," said Aimé.

### END

ELSE PRESS RELEASES FROM THIS DATE:

UK study shows improvements in life expectancy in type 1 diabetes which should now be reflected in life insurance and other relevant policies for those with the condition

2013-09-25

A study from the UK reveals that, in the population of Scotland, UK, life expectancy for people with type 1 diabetes has improved substantially, and this improvement should now be reflected in life insurance and other relevant policies for those with the condition. The research is by, Professor Helen Colhoun and Shona Livingstone, University of Dundee, UK, and colleagues on behalf of the Scottish Diabetes Research Network, and is presented at this year's annual meeting of the European Association for the Study of Diabetes (EASD) in Barcelona, Spain. "Historically those ...

Study shows social deprivation a key factor in mortality in type 1 diabetes

2013-09-25

Levels of social deprivation, as well as how well a patient controls their blood sugar, is an independent risk factor for mortality in people with type 1 diabetes. These are the findings of new research presented at this year's annual meeting of the European Association for the Study of Diabetes in Barcelona, Spain. The research is by the Diabetes Clinical Academic Group at King's Healthcare Partners, UK, and presented by Dr Stephen Thomas, Dept of Diabetes and Endocrinology, Guy's and St Thomas' Hospitals NHS Foundation Trust (GSTT), London. Despite advances in care ...

Having children lowers mortality in people with type 1 diabetes, but for women more than men

2013-09-25

New research published at this week's annual meeting of the European Association for the Study of Diabetes (EASD) in Barcelona, Spain, shows that having children lowers mortality in people with type 1 diabetes, but for women more than men. The research is by Dr Lena Sjöberg, University of Helsinki, Helsinki, Finland, and National Institute for Health and Welfare, Helsinki, Finland, and colleagues. Previous research has shown that type 1 diabetes is associated with increased mortality compared with the general population, from both acute and long-term diabetic complications. ...

'Traffic light' test could prevent hundreds of people developing alcohol-related cirrhosis

2013-09-25

A simple 'traffic light' test that detects hidden liver fibrosis and cirrhosis in high risk populations could reduce harmful drinking rates and potentially prevent hundreds of alcohol-related deaths a year. Devised by Dr Nick Sheron and colleagues at University of Southampton and Southampton General Hospital, the Southampton Traffic Light (STL) test, which costs about £50, could be used by GPs in the community. Published in the October 2013 issue of the British Journal of General Practice (BJGP), the STL appeared to help reduce drinking rates in people with the highest ...

The 'in-law effect': Male fruit flies sleep around but females keep it in the family

2013-09-25

Male fruit flies like to have a variety of sexual partners, whereas females prefer to stick with the same mate – or move on to his brothers. An Oxford University study of mating preferences in fruit flies (Drosophila) has found that males and females respond to the sexual familiarity of potential mates in fundamentally different ways. While male fruit flies preferred to court an unknown female over their previous mate or her sisters, female fruit flies displayed a predilection for their 'brothers-in-law'. These responses were significantly weaker in mutated flies ...

4-year repeat of bone mineral density screening in seniors offers limited value

2013-09-25

BOSTON – Repeating bone mineral density (BMD) tests after four years provides little clinical benefit when assessing bone fracture risk in seniors age 75 and older, according to a recent study led by researchers at the Harvard Medical School-affiliated Institute for Aging Research at Hebrew SeniorLife. The study appears in the Sept. 25 online issue of JAMA. BMD testing is an important tool in osteoporosis risk assessment and management, although there are no established guidelines for the appropriate time interval between tests. Medicare pays for BMD screening every two ...

NREL calculates emissions & costs of power plant cycling necessary for increased wind and solar

2013-09-25

New research from the Energy Department's National Renewable Energy Laboratory (NREL) quantifies the potential impacts of increasing wind and solar power generation on the operators of fossil-fueled power plants in the West. To accommodate higher amounts of wind and solar power on the electric grid, utilities must ramp down and ramp up or stop and start conventional generators more frequently to provide reliable power for their customers – a practice called cycling. The study finds that the carbon emissions induced by more frequent cycling are negligible ( END ...

NASA's Hubble and Chandra find evidence for densest nearby galaxy

2013-09-25

Astronomers using NASA's Hubble Space Telescope and Chandra X-ray Observatory and telescopes on the ground may have found the most crowded galaxy in our part of the universe. The ultra-compact dwarf galaxy, known as M60-UCD1, may be the densest galaxy near to Earth, packed with an extraordinary number of stars. This galaxy is providing astronomers with clues to its intriguing past and its role in the galactic evolutionary chain. M60-UCD1, estimated to be about 10 billion years old, is near the massive elliptical galaxy NGC 4649, also called M60, about 54 million light ...

Astronomers discover densest galaxy ever

2013-09-25

Imagine the distance between the sun and the star nearest to it – a star called Alpha Centauri. That's a distance of about 4 light years. Now, imagine as many as 10,000 of our suns crammed into that relatively small space. That is about the density of a galaxy that was recently discovered by an international team of astronomers led by a Michigan State University faculty member. "This galaxy is more massive than any ultra-compact drawfs of comparable size," said Jay Strader, MSU assistant professor of physics and astronomy, "and is arguably the densest galaxy known in ...

New study shows how ICU ventilation may trigger mental decline

2013-09-25

PHILADELPHIA— At least 30 percent of patients in intensive care units (ICUs) suffer some form of mental dysfunction as reflected in anxiety, depression, and especially delirium. In mechanically-ventilated ICU patients, the incidence of delirium is particularly high, about 80 percent, and may be due in part to damage in the hippocampus, though how ventilation is increasing the risk of damage and mental impairment has remained elusive. Now, a new study published in the American Journal of Respiratory and Critical Care Medicine from researchers at the University of Oviedo ...

Wiley advances Knowitall Solutions with new trendfinder application for user-friendly chemometric analysis and additional enhancements to analytical workflows

Genetic study pushes back timeline for first significant human population expansion

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: