Science & Technology

Evolution study finds Icelandic genomes contain more Denisovan DNA fragments than expected

genomeweb
Wed, 22 Apr 2020 13:17 UTC

© MAAYAN HAREL
This artist's reconstruction, based on anatomical estimates from a new method, shows the face of a Denisovan girl from Siberia in Russia

A team of European researchers led by DeCode Genetics' Kari Stefansson examined the effects of the admixture of modern humans and Neanderthals, and found that Icelandic genomes had more Denisovan-like DNA fragments than expected.

As the researchers described in a study published on Wednesday in Nature, they analyzed 14.4 million putative archaic chromosome fragments that were detected in fully phased whole-genome sequences from 27,566 Icelanders. These fragments corresponded to a range of 56,388 to 112,709 unique archaic fragments that covered 38 percent to 48.2 percent of the callable genome. On the basis of similarity with known archaic genomes, the researchers assigned 84.5 percent of the fragments to an Altai or Vindija Neanderthal origin and 3.3 percent to Denisovan origin, while 12.2 percent of the fragments were of unknown origin.

The unexpectedly large proportion of Denisovan DNA in the Icelandic genomes is likely explained by gene flow either into ancestors of the introgressing Neanderthals or directly into humans, the researchers said.

'Handful' of Neanderthals contributed all the interbred DNA found in modern humans, scientists find

Ciaran McGrath
Express
Sun, 19 Apr 2020 12:00 UTC

A HANDFUL of amorous Neanderthals - possibly as few as 20 individuals - are likely to have provided all the DNA originating from the species which is found in modern humans, a new study has indicated.

But the Denisovans, a lesser-understood branch of the human family, are likely to have intermixed with modern humans in at least two distinct mixing events, meaning DNA from them makes up a higher proportion of the genetic code of some populations of people living in east Asia and Oceania. The study offers the most comprehensive analysis of human genetic diversity to date, after the sequencing of 929 human genomes by scientists at the Wellcome Sanger Institute, the University of Cambridge and collaborators. It suggests Neanderthal ancestry of modern humans can be explained by just one major mixing event, probably involving several Neanderthal individuals who came into contact with modern humans shortly after the latter had expanded out of Africa.

The study's first author, Dr Anders Bergstrom, of the Francis Crick Institute and an alumnus of the Wellcome Sanger Institute, told Express.co.uk: "Our results imply that several Neanderthal individuals contributed genetic material, but it's difficult to say if it was a question of tens, or hundreds, or an even larger number.

Comment: Laura Knight-Jadczyk explored some of the possible reasons and implications behind this limited interbreeding event in her article The Golden Age, Psychopathy and the Sixth Extinction back in 2011.

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Ocean floor bacteria with unique metabolism discovered

Paul M. Sutter
Universe Today
Tue, 21 Apr 2020 12:00 UTC

Bacteria come in two basic forms: the kinds that use a lot of hydrogen, and the kinds that don't. And recently researchers think they've found a new bacteria that appear to do both at the same time, allowing it to live in a variety of extreme environments, like the ocean floor.

Its name is Acetobacterium woodii, often shortened to A. woodii, and it seems like it's a superhero of the small-sized world.

Many kinds of bacteria are anaerobic, meaning they don't use oxygen for their metabolism. You're quite familiar with these critters: they eats the sugars in foods to turn them into other yummy things, like cheese and sauerkraut. One of the byproducts of this process is the production of hydrogen, which to these bacteria is just a useless waste gas, but in too high concentrations it can disrupt their metabolism and choke them to death.

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Doctors in China report coronavirus can survive in the human eye

The Jerusalem Post
Wed, 22 Apr 2020 17:52 UTC

Coronavirus may live longer in one's eye than in other parts of the body, according to a Chinese report cited by Channel 13. The report stated that a Chinese woman was carrying the virus in her eye, while her nose was clear.

The woman, who is 65 years old, flew to Italy from the Chinese city of Wuhan where the coronavirus first broke out. She reported feeling sick on January 27 and quickly began to cough and experience high fever as well as an eye infection.

After 20 days of being in hospital, the eye infection cleared, but the virus was found in her eyes the next day. No virus was detected in her eyes or nose after that date, but on her 27th day in the hospital the virus was discovered again in her eyes.

The report claimed that the virus can replicate even when it is no longer detectable, meaning the infection potential exists even when patients seem to be healthy.

Iran's IRGC launches its first military satellite into orbit

Oleg Burunov
Sputnik
Wed, 22 Apr 2020 05:29 UTC

Iran has successfully sent into orbit its first military satellite, the country's Tasnim news agency reported on Wednesday.

The satellite called Noor (Light) was put into an orbit located 425 kilometres (624 miles) above the Earth's surface via a two-stage carrier called Qassed (Envoy).

The launch, which was conducted by the Islamic Revolutionary Guards Corps (IRGC), comes after Iranian Defence Minister Amir Hatami in February rejected allegations issued by the US that the satellite carriers could be turned into military missiles and that the recent unsuccessful launch of a Zafar satellite was part of Iran's missile programme.

"The satellite launch and satellite carrier [...] are not related to missile [programme]", Hatami pointed out.

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Fomalhaut b: Astronomers discover planet that never was

Daniel Stolte, University of Arizona
Phys.org
Mon, 20 Apr 2020 06:26 UTC

This artist's illustration depicts the collision of two 125-mile-wide icy, dusty bodies orbiting the bright star Fomalhaut, located 25 light-years away

© ESA, NASA and M. Kornmesser
Clash of Titans: This artist's illustration depicts the collision of two 125-mile-wide icy, dusty bodies orbiting the bright star Fomalhaut, located 25 light-years away.

What astronomers thought was a planet beyond our solar system has now seemingly vanished from sight, suggesting that what was heralded as one of the first exoplanets to ever be discovered with direct imaging likely never existed.

Two University of Arizona astronomers conclude that NASA's Hubble Space Telescope was instead looking at an expanding cloud of very fine dust particles from two icy bodies that smashed into each other. Hubble came along too late to witness the suspected collision but may have captured its aftermath. The missing-in-action planet was last seen orbiting the star Fomalhaut, 25 light years away.

"These collisions are exceedingly rare and so this is a big deal that we actually get to see evidence of one," said Andras Gaspar, an assistant astronomer at the University of Arizona's Steward Observatory and lead author of a research paper announcing the discovery. "We believe that we were at the right place at the right time to have witnessed such an unlikely event with NASA's Hubble Space Telescope."

"The Fomalhaut star system is the ultimate test lab for all of our ideas about how exoplanets and star systems evolve," added George Rieke, a Regents Professor of Astronomy at Steward Observatory. "We do have evidence of such collisions in other systems, but none of this magnitude has been observed in our solar system. This is a blueprint of how planets destroy each other."

Neolithic genomes from modern-day Switzerland indicate parallel ancient societies

Max Planck Institute
Mon, 20 Apr 2020 12:00 UTC

© Switzerland Urs Dardel, Archäologischer Dienst des Kanton Bern
Top view of the Dolmen of Oberbipp, one of the largest burial sites in the study.

Genetic research throughout Europe shows evidence of drastic population changes near the end of the Neolithic period, as shown by the arrival of ancestry related to pastoralists from the Pontic-Caspian steppe. But the timing of this change and the arrival and mixture process of these peoples, particularly in Central Europe, is little understood. In a new study published in Nature Communications, researchers analyze 96 ancient genomes, providing new insights into the ancestry of modern Europeans.

Scientists sequence almost one hundred ancient genomes from Switzerland

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Folium: The mysterious Medieval blue dye that eluded researchers until now

Unviersidade Nova de Lisboa
Mon, 20 Apr 2020 12:00 UTC

An interdisciplinary team of LAQV researchers from NOVA University Lisbon, University of Porto and University of Aveiro, unveiled the complex chemical structure of the medieval purple-blue dye used in the illumination of medieval manuscripts. The elucidation of the chemical structure of the medieval folium dye was a mystery until now, despite the efforts of several international research teams since the 20th century. The results obtained in this research work are an important contribution to the preservation of our cultural heritage and are now published in the high-impact journal Science Advances.

The study was developed by LAQV chemists and conservation and restoration researchers, specialists in the identification of natural products and the reproduction of medieval colors, and counted on the collaboration of a biologist from the University of Lisbon with extensive knowledge of Portuguese flora who supervised the collection of fruits and allowed to find and identify the mysterious small plant, Chrozophora tinctoria.

Comment: See also:

Coronavirus has mutated into at least 30 different strains new study finds

Alex Winston
The Jerusalem Post
Tue, 21 Apr 2020 21:49 UTC

The study was carried out by Professor Li Lanjuan and colleagues from Zhejiang University in Hangzhou, China and published in a non-peer reviewed paper released on website medRxiv.org on Sunday.

A new study in China has found that the novel coronavirus has mutated into at least 30 different variations.The results showed that medical officials have vastly underestimated the overall ability of the virus to mutate, in findings that different strains have affected different parts of the world, leading to potential difficulties in finding an overall cure.

The study was carried out by Professor Li Lanjuan and colleagues from Zhejiang University in Hangzhou, China and published in a non-peer reviewed paper released on website medRxiv.org on Sunday.

Collapse of Eurasian Ice Sheet 14,600 years ago raised seas by eight metres

Patrick Galey
Phys.org
Mon, 20 Apr 2020 21:51 UTC

At the time the Eurasian ice sheet covered much of Scandinavia

The melting of the Eurasian ice sheet around 14,000 years ago lifted global sea levels by about eight metres, according to new research published Monday that highlights the risks of today's rapid ice cap melt.

Earth's last Glacial Maximum period began around 33,000 years ago, when vast ice sheets covered much of the Northern Hemisphere.

At the time, the Eurasian ice sheet — which covered much of Scandinavia — contained approximately three times the amount of frozen water held in the modern-day Greenland ice sheet.

But rapid regional warming saw the ice sheet collapse over a period of just 500 years, according to authors of the study published in Nature Geoscience.

Comment: For insight into what cataclysmic events may have brought about the collapse of the Eurasian Ice Sheet, see:

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Science & Technology

Evolution study finds Icelandic genomes contain more Denisovan DNA fragments than expected

'Handful' of Neanderthals contributed all the interbred DNA found in modern humans, scientists find

Ocean floor bacteria with unique metabolism discovered

Doctors in China report coronavirus can survive in the human eye

Iran's IRGC launches its first military satellite into orbit

Fomalhaut b: Astronomers discover planet that never was

Neolithic genomes from modern-day Switzerland indicate parallel ancient societies

Folium: The mysterious Medieval blue dye that eluded researchers until now

Coronavirus has mutated into at least 30 different strains new study finds

Collapse of Eurasian Ice Sheet 14,600 years ago raised seas by eight metres

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