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Posts Tagged ‘human beings

[LINK] On evidence of Australian Aborigine ancestry in Amazonia

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The Nature paper “Genetic evidence for two founding populations of the Americas” has a remarkable abstract.

Genetic studies have consistently indicated a single common origin of Native American groups from Central and South America. However, some morphological studies have suggested a more complex picture, whereby the northeast Asian affinities of present-day Native Americans contrast with a distinctive morphology seen in some of the earliest American skeletons, which share traits with present-day Australasians (indigenous groups in Australia, Melanesia, and island Southeast Asia) Here we analyse genome-wide data to show that some Amazonian Native Americans descend partly from a Native American founding population that carried ancestry more closely related to indigenous Australians, New Guineans and Andaman Islanders than to any present-day Eurasians or Native Americans. This signature is not present to the same extent, or at all, in present-day Northern and Central Americans or in a ~12,600-year-old Clovis-associated genome, suggesting a more diverse set of founding populations of the Americas than previously accepted.

The Smithsonian goes into more detail.

Genetic studies have since connected both these ancient and modern humans to ancestral populations in Eurasia, adding to the case that a single migratory surge produced the first human settlers in the Americas. Aleutian Islanders are a notable exception. They descend from a smaller second influx of Eurasians 6,000 years ago that bear a stronger resemblance to modern populations, and some Canadian tribes have been linked to a third wave.

[David] Reich’s group had also previously found genetic evidence for a single founding migration. But while sifting through genomes from cultures in Central and South America, Pontus Skoglund, a researcher in Reich’s lab, noticed that the Suruí and Karitiana people of the Amazon had stronger ties to indigenous groups in Australasia—Australians, New Guineans and Andaman Islanders—than to Eurasians.

Other analyses haven’t looked at Amazonian populations in depth, and genetic samples are hard to come by. So the Harvard lab teamed up with researchers in Brazil to collect more samples from Amazonian groups to investigate the matter. Together they scrutinized the genomes of 30 Native American groups in Central and South America. Using four statistical strategies, they compared the genomes to each other and to those of 197 populations from around the world. The signal persisted. Three Amazonian groups—Suruí, Karitiana and Xavante—all had more in common with Australasians than any group in Siberia.

The DNA that links these groups had to come from somewhere. Because the groups have about as much in common with Australians as they do with New Guineans, the researchers think that they all share a common ancestor that lived tens of thousands of years ago in Asia but that doesn’t otherwise persist today. One branch of this family tree moved north to Siberia, while the other spread south to New Guinea and Australia. The northern branch likely migrated across the land bridge in a separate surge from the Eurasian founders. The researchers have dubbed this hypothetical second group “Population y” for ypykuéra, or “ancestor” in Tupi, a language spoken by the Suruí and Karitiana.

When exactly Population y arrived in the Americans remains unclear—before, after or simultaneously with the first wave of Eurasians are all possibilities. Reich and his colleagues suspect the line is fairly old, and at some point along the way, Population y probably mixed with the lineage of Eurasian settlers. Amazonian tribes remain isolated from many other South American groups, so that’s probably why the signal remains strong in their DNA.

Written by Randy McDonald

July 22, 2015 at 10:42 pm

[URBAN NOTE] On how Torontonians (and other humans) benefit from trees

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A post on Discover magazine’s Inkfish blog alerted me to some interesting research.

What’s a tree worth to you? According to a large study in Toronto, trees may increase both how healthy you feel and how healthy you really are. Having some extra foliage on your block could be as good for your health as a pay raise–or an anti-aging machine.

It’s a complicated relationship to figure out, because variables that affect how many trees you see each day could also affect your health. The population of a concrete, inner-city apartment complex may have socioeconomic differences, for example, from the population of a leafy, well-tended suburb. University of Chicago psychologist Marc Berman and his colleagues used a detailed analysis to try to tease out the impact of trees themselves.

They started by going to Canada. In a country with universal health care, they figured, access to doctors isn’t as much of a variable as in the United States. Since socioeconomic status can still affect how people use doctors, the authors also gathered information on their subjects’ income and education. And rather than comparing people from multiple areas, they focused only on the city of Toronto.

From a large-scale, ongoing project called the Ontario Health Study, the authors collected data on over 31,000 adult residents of Toronto. In addition to household income and years of education, they looked at subjects’ sex, diet (self-reported servings of fruits and vegetables per day), and neighborhood. The Ontario Health Study questionnaires also asked subjects whether they’d ever been diagnosed with various physical and mental health conditions.

The final measurement was health perception: how healthy do subjects feel they are, on a scale from 1 to 5? It sounds vague, but this measurement has been found to strongly predict actual health, the authors write.

The Toronto Star‘s Geoffrey Vendeville went into more detail.

Using data from Toronto, a team of researchers has found that having 10 more trees on your block has self-reported health benefits akin to a $10,000 salary raise or moving to a neighbourhood with a $10,000 higher median income or being seven years younger.

By comparing satellite imagery of Toronto, an inventory of trees on public land and general health surveys, the team, led by University of Chicago psychologist Marc Berman, found that people who live on a tree-lined block are less likely to report conditions such as high blood pressure, obesity, heart disease or diabetes.

Their findings appeared last week in the open-access journal Scientific Reports.

The study suggests “pretty strongly” that planting 4 per cent more trees would have significant health benefits, Berman said.

Researchers don’t know why, exactly, trees seem to be good for people’s health.

“Is it that the trees are cleaning the air? Is it that the trees are encouraging people to go outside and exercise more? Or is it their esthetic beauty? We need to understand that,” he said.

Written by Randy McDonald

July 15, 2015 at 6:49 pm

[BLOG] Some Thursday links

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  • Centauri Dreams argues that humans have a deep-seated instinct to explore.
  • Crooked Timber looks at how Greek debt is a political problem.
  • The Dragon’s Gaze notes an unsuccessful search for gas giant exoplanets around a white dwarf and looks at a new system for classifying exoplanets by mass.
  • The Dragon’s Tales looks at a report that a Patriot missile battery in Turkey got hacked.
  • Geocurrents notes how the eastern Yemeni region of Al Mahrah is seeking autonomy.
  • Lawyers, Guns and Money notes the failure of the United States’ Cuban embargo.
  • Marginal Revolution speculates as to the peculiar dynamics of political leadership in China.
  • Personal Reflections’ Jim Belshaw reflects on Greece.
  • The Planetary Society Blog notes that Pluto can now be explored via Google Earth.
  • Registan looks at the decline of Tajikistan’s Islamic Renaissance Party.
  • Strange Maps shares a map that charts out the City of London and its threats.
  • Towleroad notes an upcoming vote over a civil partnership bill in Cyprus.
  • Window on Eurasia reports that most books published in Russia have small print runs.

[LINK] “Ancient Romanian jawbone sheds light on Neanderthal interbreeding”

The Globe and Mail hosts Will Dunham’s Reuters article reporting that an ancient Homo sapiens skeleton in Romania has substantial Neanderthal ancestry. That this skeleton does not belong to a population that left descendants in contemporary Europe is also noteworthy, IMHO.

You may not know it, but you probably have some Neanderthal in you. For people around the world, except sub-Saharan Africans, about 1 to 3 percent of their DNA comes from Neanderthals, our close cousins who disappeared roughly 39,000 years ago.

Scientists said on Monday a jawbone unearthed in Romania, of a man who lived about 40,000 years ago, boasts the most Neanderthal ancestry ever seen in a member of our species.

[. . .]

“We show that one of the very first modern humans that is known from Europe had a Neanderthal ancestor just four to six generations back in his family tree,” said geneticist Svante Pääbo of Germany’s Max Planck Institute for Evolutionary Anthropology.

“He carries more Neanderthal DNA than any other present-day or ancient modern human seen to date.”

Harvard Medical School geneticist David Reich said 6 to 9 percent of this individual’s genome derived from a Neanderthal ancestor.

Written by Randy McDonald

June 22, 2015 at 7:04 pm

[BLOG] Some Friday links

  • blogTO notes that Diner en blanc will be returning to Toronto this summer.
  • D-Brief observes that DNA testing of the skeleton of Kennewick Man reveals the person to have been of indigenous American background.
  • The Dragon’s Gaze links to a paper making the case for circumbinary exoplanets orbiting compact binaries.
  • The Dragon’s Tales notes the controversy over the question of whether flooding doomed pre-Columbian Cahokia.
  • In the aftermath of the Charleston tragedy, Lawyers, Guns and Money notes the close linkage of the Confederate flag to racism.
  • Marginal Revolution looks at rhetoric of austerity in Greece.
  • The New APPS Blog considers the inhibitory role of copyright in popular culture.
  • Personal Reflections’ Jim Belshaw muses that the clash of ideologies is fundamentally irrelevant to Australian life, that things work differently than left versus right.
  • The Planetary Society Blog notes transient hot spots on Venus indicative of volcanism.
  • Peter Rukavina celebrated Autism Acceptance Day yesterday, and his son Oliver.
  • Mark Simpson notes the ridiculous rhetoric of masculinity with commercial products.
  • Speed River Journals’ Van Waffle celebrates the rebirth of St. Jacob’s Farmer’s Market.
  • Towleroad shares a video of Lady Gaga’s stunning performance of “Imagine.”
  • Window on Eurasia is skeptical about the prospects of the Russian economy and argues Ukrainians should not hope for much from Russia.

[BLOG] Some Thursday links

  • The Broadside Blog’s Caitlin Kelly wonders who we should trust.
  • Centauri Dreams notes the discovery of Kepler-138b, a Mars-sized exoplanet orbiting a red dwarf star.
  • Cody Delistraty considers whether language influences morality.
  • Geocurrents’ Martin Lewis shares different scenarios for the breakup of Nigeria.
  • Lawyers, Guns and Money notes the oppression of women workers.
  • Marginal Revolution argues that there is a skills shortage in the American economy and is in favour of the TPP trade agreement.
  • Steve Munro shares plans for TTC improvement.
  • The Russian Demographics Blog notes how Russia’s neighbours see it as a greater or lesser threat.
  • Torontoist and Transit Toronto react to the extension of cell service into the subways.
  • Window on Eurasia notes how Ukrainian Baptists in the Donbas resist Russian influence and argues that Russian militarization will ultimately hurt Russians.

[BLOG] Some Wednesday links

  • The Big Picture has a photo essay about albino children in Panama.
  • Crooked Timber considers African-American radicalism.
  • The Dragon’s Gaze links to one paper imagining the frequency of habitable planets in other universes, and links to another suggesting that to host habitable worlds exoplanet systems will need their worlds to have aligned orbits.
  • Joe. My. God. notes that police in Seoul cannot halt the Pride parade.
  • Language Hat reports on a pavilion at the Venice Biennale featuring Native American languages.
  • Marginal Revolution notes that 19th century Chinese bet on the outcome of student exams.
  • The Power and the Money’s Noel Maurer notes the crackdown on money laundering has not hit the average Mexican.
  • Savage Minds considers race from the perspective of a library cataloguer.
  • Torontoist notes a local call for ghost bikes.
  • Window on Eurasia notes the repression of Crimean Tatars, notes a Chinese proposal for settlement in Siberia, and looks at how the war in Ukraine has given nuclear weapons new life.
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