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Indian-origin scientists find South Asians sharing ancestry with a mysterious population

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Denisovans were probably dark-skinned, unlike the pale Neandertals.n Image source: sci-news.com

New York: Indian-origin scientists among others have found that many bloodlines around the world, particularly of South Asian descent, may actually be a bit more Denisovan- a mysterious population of hominids.

Denisovans lived around the same time as the Neanderthals- researchers including Indian-origin scientists have revealed.

The team from Harvard Medical School and University of California-Los Angeles (UCLA) has created a world map and also used comparative genomics to make predictions about where Denisovan and Neanderthal genes may be impacting modern human biology.

The analysis also proposes that modern humans interbred with Denisovans about 100 generations after their trysts with the Neanderthals.

Denisovan genes can potentially be linked to a more subtle sense of smell in Papua New Guineans and high-altitude adoptions in Tibetans.

Meanwhile, Neanderthal genes found in people around the world most likely contribute to tougher skin and hair.

Most non-Africans possess at least a little bit Neanderthal DNA.

“There are certain classes of genes that modern humans inherited from the archaic humans with whom they interbred, which may have helped the modern humans to adapt to the new environments in which they arrived,” explained senior author David Reich, a geneticist at Harvard Medical School.

On the flip side, there was negative selection to systematically remove ancestry that may have been problematic from modern humans.

“We can document this removal over the 40,000 years since these admixtures occurred,” Reich added.

Reich and lab members, Swapan Mallick and Nick Patterson, teamed up with previous laboratory member Sriram Sankararaman, assistant professor of computer science at the University of California, Los Angeles for the project.

They found evidence that both Denisovan and Neanderthal ancestry has been lost from the X chromosome as well as genes expressed in the male testes.

The team theorises that this has contributed to reduced fertility in males, which is commonly observed in other hybrids between two highly divergent groups of the same species.

The researchers collected their data by comparing known Neanderthal and Denisovan gene sequences across more than 250 genomes from 120 non-African populations publicly available through the Simons Genome Diversity Project.

The analysis was carried out by a machine-learning algorithm that could differentiate between components of both kinds of ancestral DNA, which are more similar to one another than to modern humans.

The study’s limitation is that it relies on the current library of ancient genomes available.

“We can’t use this data to make claims about what the Denisovans or Neanderthals looked like, what they ate, or what kind of diseases they were susceptible to,” said Sankararaman, first author on the paper. “We are still very far from understanding that.”

The new map of archaic ancestry was published in the journal Current Biology. (IANS)

  • Shriya Katoch

    This is really interesting . The idea that South Asians may have a mix of Denisovan with them is fascinating .

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Stars’ ‘DNA’ could help scientists find Sun’s lost siblings

Unfortunately, astronomers cannot collect the DNA of a star with a mouth swab but instead use the starlight, with a technique called spectroscopy

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UFO religion as a concept is now becoming a part of popular understanding.
Countless galaxies exist in the universe, each hiding secrets that humankind is yet to unearth. Pixabay

With the aim to find the lost siblings of the Sun, now scattered across the sky, a team of astronomers has collected the “DNA” of more than 340,000 stars in the Milky Way.

The “DNA” can help trace the ancestry of stars, showing astronomers how the universe went from having only hydrogen and helium — just after the Big Bang — to being filled today with all the elements we have here on Earth that are necessary for life.

Little Cub galaxy
Scientists to find sun’s lost siblings. Wikimedia Commons

The research, detailed in the journal Monthly Notices of the Royal Astronomical Society, is based on the Galactic Archaeology survey, called GALAH, launched in late 2013 as part of a quest to uncover the formulation and evolution of galaxies. When complete, GALAH will investigate more than a million stars.

The GALAH survey used the HERMES spectrograph at the Australian Astronomical Observatory’s (AAO) 3.9-metre Anglo-Australian Telescope near Coonabarabran in New South Wales to collect spectra for the 340,000 stars. “No other survey has been able to measure as many elements for as many stars as GALAH,” said Gayandhi De Silva of the University of Sydney and AAO.

Also Read: Next Planet-Hunting Mission Of NASA Postponed

“This data will enable such discoveries as the original star clusters of the Galaxy, including the Sun’s birth cluster and solar siblings — there is no other dataset like this ever collected anywhere else in the world,” De Silva said.

The Sun, like all stars, was born in a group or cluster of thousands of stars, explained Sarah Martell from the University of New South Wales (UNSW) Sydney who leads the GALAH survey observations. “Every star in that cluster will have the same chemical composition, or DNA – these clusters are quickly pulled apart by our Milky Way Galaxy and are now scattered across the sky,” Martell said.

Black hole in milky way
Scientists are collecting DNA of stars. VOA

“The GALAH team’s aim is to make DNA matches between stars to find their long-lost sisters and brothers,” she added. For each star, this DNA is the amount they contain of each of nearly two dozen chemical elements such as oxygen, aluminium and iron.

Unfortunately, astronomers cannot collect the DNA of a star with a mouth swab but instead use the starlight, with a technique called spectroscopy. The light from the star is collected by the telescope and then passed through an instrument called a spectrograph, which splits the light into detailed rainbows, or spectra. IANS