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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)

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Just in! Like Computer Software, Scientists can now Programme Cells in your Body to Fight Diseases!

Scientists found that RNA which is produced abundantly by humans, plants and animals can be genetically engineered to allow scientists to programme cells with specific commands

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Scientists have found that cells can be programmed with pre-defined RNA commands, in the manner of a computer's microprocessor VOA

London, September 19, 2017 : A new technique can help programme cells like a computer to fight cancer, influenza, and other serious conditions, suggests new research.

A common molecule — ribonucleic acid (RNA), which is produced abundantly by humans, plants and animals — can be genetically engineered to allow scientists to programme cells, said the study published in the journal Nucleic Acids Research.

RNAs carry information between protein and DNA in cells, and the research proved that these molecules can be produced and organised into tailor-made sequences of commands — similar to codes for computer software — which feed specific instructions into cells, programming them to do what we want.

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Cells have the capacity to process and respond to instructions and codes inputted into their main system, said lead researcher Alfonso Jaramillo, Professor at University of Warwick in Britain.

Similar to software running on a computer, or apps on a mobile device, many different RNA sequences could be created to empower cells with a ‘Virtual Machine’, able to interpret a universal RNA language, and to perform specific actions to address different diseases or problems, the study said.

This will allow a novel type of personalised and efficient healthcare, allowing us to ‘download’ a sequence of actions into cells, instructing them to execute complex decisions encoded in the RNA.

The researchers made their invention by first modelling all possible RNA sequence interactions on a computer, and then constructing the DNA encoding the optimal RNA designs, to be validated on bacteria cells in the laboratory.

After inducing the bacterial cells to produce the genetically engineered RNA sequences, the researchers observed that they had altered the gene expression of the cells according to the RNA programme — demonstrating that cells can be programmed with pre-defined RNA commands, in the manner of a computer’s microprocessor.

ALSO READ Zika Virus Fight: FDA Plans To Exterminate Disease With Genetically Modified Mosquitoes

“The capabilities of RNA molecules to interact in a predictable manner, and with alternative conformations, has allowed us to engineer networks of molecular switches that could be made to process arbitrary orders encoded in RNA,” Jaramillo said.

As well as fighting disease and injury in humans, scientists could harness this technique to control plant cells and reverse environmental and agricultural issues, making plants more resilient to disease and pests.

“Throughout last year, my group has been developing methodologies to enable RNA sensing the environment, perform arithmetic computations and control gene expression without relying on proteins, which makes the system universal across all living kingdoms,” Jaramillo said.

“The cells could read the RNA ‘software’ to perform the encoded tasks, which could make the cells detect abnormal states, infections, or trigger developmental programmes,” he added.  (IANS)

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‘It is Definitely a Woman’ ; DNA tests Reveal First Strong Evidence of a Female Viking Warrior

The researchers say it's the first confirmed remains of a high-ranking female Viking warrior

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Programme cells
Scientists have found that cells can be programmed with pre-defined RNA commands, in the manner of a computer's microprocessor VOA

Berlin, September 12, 2017 : Scientists say DNA tests on a skeleton found in a lavish Viking warrior’s grave in Sweden show the remains are those of a woman in her 30s.

While bone experts had long suspected the remains belong to a woman, the idea had previously been dismissed despite other accounts supporting the existence of female Viking warriors.

Swedish researchers used new methods to analyze genetic material from the 1,000-year-old bones at a Viking-era site known as Birka, near Stockholm.

Charlotte Hedenstierna-Jonson of Uppsala University said Monday the tests show “it is definitely a woman.”

Hedenstierna-Jonson said the grave is particularly well-furnished, with a sword, shields, various other weapons and horses.

Writing in the American Journal of Physical Anthropology, the researchers say it’s the first confirmed remains of a high-ranking female Viking warrior.

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Checkpoint Protein (CHK2) Inhibitor Drug to Protect Women’s Infertility Post Cancer Treatments

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Sep 02, 2017: An existing drug may one day protect premenopausal women from infertility that commonly follows cancer treatments, new research has found.

Women who are treated for cancer with radiation or certain chemotherapy drugs are commonly rendered sterile.

Women are born with a lifetime reserve of oocytes, or immature eggs, but those oocytes are among the most sensitive cells in the body and may be wiped out by such cancer treatments.

The new findings, published in the journal Genetics, raises hope of curbing infertility from cancer treatment.

The study builds on his 2014 research that identified a so-called checkpoint protein (CHK2) that becomes activated when oocytes are damaged by radiation.

Checkpoint protein functions in a pathway that eliminates oocytes with DNA damage, a natural function to protect against giving birth to offspring bearing new mutations.

When the researchers irradiated mice lacking the CHK2 gene, the oocytes survived, eventually repaired the DNA damage, and the mice gave birth to healthy pups.

Also Read: Treatment with Uterine Fibroids helps to restore Fertility in Women

The new study explored whether the checkpoint 2 pathway could be chemically inhibited.

“It turns out there were pre-existing CHK2 inhibitor drugs that were developed, ironically enough, for cancer treatment, but they turned out not to be very useful for treating cancer,” said study senior author John Schimenti, Professor at Cornell University in New York.

“By giving mice the inhibitor drug, a small molecule, it essentially mimicked the knockout of the checkpoint gene,” first author Vera Rinaldi, a graduate student in Schimenti’s lab, said.

By inhibiting the checkpoint pathway, the oocytes were not killed by radiation and remained fertile, enabling birth of normal pups, the study said.

“While humans and mice have different physiologies, and there is much work to be done to determine safe and effective dosages for people, it is clear that we have the proof of principle for this approach,” Schimenti said. (IANS)