Subscribe to our free daily newsletters
. Earth Science News .




Subscribe to our free daily newsletters



ABOUT US
In saliva, clues to a 'ghost' species of ancient human
by Staff Writers
Buffalo NY (SPX) Jul 25, 2017


Given the rate that genes mutate during the course of evolution, the team calculated that the ancestors of people who carry the Sub-Saharan MUC7 variant interbred with another ancient human species as recently as 150,000 years ago, after the two species' evolutionary path diverged from each other some 1.5 to 2 million years ago.

In saliva, scientists have found hints that a "ghost" species of archaic humans may have contributed genetic material to ancestors of people living in Sub-Saharan Africa today.

The research adds to a growing body of evidence suggesting that sexual rendezvous between different archaic human species may not have been unusual.

Past studies have concluded that the forebears of modern humans in Asia and Europe interbred with other early hominin species, including Neanderthals and Denisovans. The new research is among more recent genetic analyses indicating that ancient Africans also had trysts with other early hominins.

"It seems that interbreeding between different early hominin species is not the exception - it's the norm," says Omer Gokcumen, PhD, an assistant professor of biological sciences in the University at Buffalo College of Arts and Sciences.

"Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva," he says. "When we looked at the history of the gene that codes for the protein, we see the signature of archaic admixture in modern day Sub-Saharan African populations."

The research was published on July 21 in the journal Molecular Biology and Evolution. The study was led by Gokcumen and Stefan Ruhl, DDS, PhD, a professor of oral biology in UB's School of Dental Medicine.

A tantalizing clue in saliva
The scientists came upon their findings while researching the purpose and origins of the MUC7 protein, which helps give spit its slimy consistency and binds to microbes, potentially helping to rid the body of disease-causing bacteria.

As part of this investigation, the team examined the MUC7 gene in more than 2,500 modern human genomes. The analysis yielded a surprise: A group of genomes from Sub-Saharan Africa had a version of the gene that was wildly different from versions found in other modern humans.

The Sub-Saharan variant was so distinctive that Neanderthal and Denisovan MUC7 genes matched more closely with those of other modern humans than the Sub-Saharan outlier did.

"Based on our analysis, the most plausible explanation for this extreme variation is archaic introgression - the introduction of genetic material from a 'ghost' species of ancient hominins," Gokcumen says. "This unknown human relative could be a species that has been discovered, such as a subspecies of Homo erectus, or an undiscovered hominin. We call it a 'ghost' species because we don't have the fossils."

Given the rate that genes mutate during the course of evolution, the team calculated that the ancestors of people who carry the Sub-Saharan MUC7 variant interbred with another ancient human species as recently as 150,000 years ago, after the two species' evolutionary path diverged from each other some 1.5 to 2 million years ago.

Why MUC7 matters
The scientists were interested in MUC7 because in a previous study they showed that the protein likely evolved to serve an important purpose in humans.

In some people, the gene that codes for MUC7 holds six copies of genetic instructions that direct the body to build parts of the corresponding protein. In other people, the gene harbors only five sets of these instructions (known as tandem repeats).

Prior studies by other researchers found that the five-copy version of the gene protected against asthma, but Gokcumen and Ruhl did not see this association when they ran a more detailed analysis.

The new study did conclude, however, that MUC7 appears to influence the makeup of the oral microbiome, the collection of bacteria within the mouth. The evidence for this came from an analysis of biological samples from 130 people, which found that different versions of the MUC7 gene were strongly associated with different oral microbiome compositions.

"From what we know of MUC7, it makes sense that people with different versions of the MUC7 gene could have different oral microbiomes," Ruhl says. "The MUC7 protein is thought to enhance the ability of saliva to bind to microbes, an important task that may help prevent disease by clearing unwanted bacteria or other pathogens from the mouth."

Research paper

ABOUT US
Startup touts neuro-stimulation as 'medicine for the brain'
Aspen, United States (AFP) July 19, 2017
They look like a set of fancy headphones. But a set of spikes inside the band act as electrodes to stimulate the brain. According to California startup Halo Neuroscience, the device can help improve the performance of athletes, pilots and surgeons, and potentially help rehabilitation for stroke victims. "The brain is an electrical organ," said Daniel Chao, a physician and co-founder of H ... read more

Related Links
University at Buffalo
All About Human Beings and How We Got To Be Here


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ABOUT US
Smart sensors could save lives

New phase change mechanism could lead to new class of chemical vapor sensors

Robot finds possible melted fuel inside Fukushima reactor

Cheap 3D printed prosthetics could be game changer for Nepal

ABOUT US
Writing with the electron beam: Now in silver

Scientists announce the quest for high-index materials

A new synthesis route for alternative catalysts of noble metals

Synthetic materials systems that can "count" and sense their size

ABOUT US
Coral gardening is benefiting Caribbean reefs

Vietnam says four fishermen wounded by Indonesian navy

Coastal armoring and its ecological effects in soft sediment environments

Health risk alarm over water rationing in Rome

ABOUT US
A new model yields insights into glaciers' retreats and advances

NASA flights gauge summer sea ice melt in the Arctic

Thawing permafrost releases old greenhouse gas

Microbe study highlights Greenland ice sheet toxicity

ABOUT US
Disneyland China falls a-fowl of huge turkey leg demand

French grape harvest heading to historic low

Kenyan cattle herders defend 'necessary' land invasions

Using treated graywater for irrigation is better for arid environments

ABOUT US
Floodwaters swallow Myanmar pagoda

Eight more dead in India's worsening monsoon floods

25 found dead as toll from Indian floods nears 120: officials

Crustal limestone platforms feed carbon to many of Earth's arc volcanoes

ABOUT US
Two German UN peacekeepers killed in Mali helicopter crash

China warns Botswana over Dalai Lama visit

Peace deal eludes Senegal's Casamance, 35 years on

Rwandan forces killing suspects without trial: HRW

ABOUT US
How did early humans survive aridity and prolonged drought in Africa

In saliva, clues to a 'ghost' species of ancient human

Artifacts suggest humans arrived in Australia earlier than thought

Startup touts neuro-stimulation as 'medicine for the brain'




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement