Tuesday October 23, 2018
Home World Why is Neande...

Why is Neanderthal Genetic material Found in only Small amount in Genomes of Modern Humans?

The scientists estimated that these gene variations were able to persist in Neanderthals because Neanderthals had a much smaller population size than humans

0
//
96
FILE - A model of an adult Neanderthal male head and shoulders by artist John Gurche on display in the Hall of Human Origins in the Smithsonian Museum of Natural History in Washington, D.C. VOA
Republish
Reprint

New York, November 9, 2016: Neanderthal genetic material is found in only small amount in the genomes of modern humans because, after inter-breeding, natural selection removed large numbers of weakly deleterious Neanderthal gene variants, says a study.

Humans and Neanderthals inter-bred tens of thousands of years ago, but today, Neanderthal DNA makes up only one to four per cent of the genomes of modern non-African people.

NewsGram brings to you current foreign news from all over the world.

[bctt tweet=”Scientists found that natural selection removed many Neanderthal alleles from the genome that might have had mildly negative effects. ” username=””]

“For a while now we have known that humans and Neanderthals hybridised. Many Europeans and Asians – along with other non-African populations – are the descendants of those hybrids,” said Ivan Juric from the University of California, Davis in the US.

“Previous work has also shown that, following hybridisation, many Neanderthal gene variants were lost from the modern human population due to selection. We wanted to better understand the causes of this loss,” Juric noted.

To understand how modern humans lost their Neanderthal genetic material and how humans and Neanderthals remained distinct, the researchers developed a novel method for estimating the average strength of natural selection against Neanderthal genetic material.

NewsGram brings to you top news around the world today.

They found that natural selection removed many Neanderthal alleles from the genome that might have had mildly negative effects.

The scientists estimated that these gene variations were able to persist in Neanderthals because Neanderthals had a much smaller population size than humans.

Once transferred into the human genome, however, these alleles became subject to natural selection, which was more effective in the larger human populations and has removed these gene variants over time.

“Our results are compatible with a scenario where the Neanderthal genome accumulated many weakly deleterious variants, because selection was not effective in the small Neanderthal populations. Those variants entered the human population after hybridisation,” Juric said.

Check out NewsGram for latest international news updates.

“Once in the larger human population, those deleterious variants were slowly purged by natural selection,” Juric noted.

These findings, published in the journal PLOS Genetics, shed new light on the role of population size on losing or maintaining Neanderthal ancestry in humans. (IANS)

Click here for reuse options!
Copyright 2016 NewsGram

Next Story

Novel Synthetic DNA Vaccines Safe To Use Against Ebola: Scientists

While there are no licensed treatments available for Ebola virus disease yet, multiple experimental therapies are being developed.

0
Ebola, UNICEF. congo, DNA
A Congolese health worker administers Ebola vaccine to a woman who had contact with an Ebola sufferer in the village of Mangina in North Kivu province of the Democratic Republic of Congo

Scientists, including one of Indian-origin, have found that the novel synthetic DNA vaccine is safe against Ebola virus and offers a long-term alternative to traditional vaccines.

The team, from The Wistar Institute in Philadelphia, US, optimised a shorter, dose-sparing, immunisation regimen and simplified vaccine that can be directly administered into the skin. They targeted a virus surface protein called glycoprotein.

This new approach induced rapid and protective immunity from virus challenges.

Importantly, the approach showed strong immune responses one year after the last dose, supporting the long-term immunogenicity of the vaccine — a particularly challenging area for Ebola vaccines.

Ebola, UNICEF. congo, DNA
A boy runs past a dispenser containing water mixed with disinfectant, east of Mbandaka, DRC. VOA

“Synthetic non-viral based DNA technology allows for rapid vaccine development by delivery directly into the skin, resulting in consistent, potent and rapid immunity compared to traditional vaccine approaches,” said lead researcher David B. Weiner, Director of Wistar’s Vaccine and Immunotherapy Center.

“An anti-Ebola virus DNA vaccine like this may provide an important new tool for protection, and we are excited to see what future studies will unveil,” he added.

In the study, published in the Journal of Infectious Diseases, the team detected antibody levels were equal or higher to those reported for other vaccines currently being evaluated in the clinic.

“The success of intradermal delivery of a low-dose regimen is very encouraging,” said Ami Patel, Ph.D., associate staff scientist in the Weiner Lab. “The ultimate goal of our work is to create effective and safe vaccines that are optimised for field use in at-risk areas.”

Ebola, UNICEF. congo, DNA
Photo taken Sept 9, 2018, shows health workers walking with a boy suspected of having the Ebola virus at an Ebola treatment centre in Beni, Eastern Congo. VOA

Ebola virus disease is a serious and often fatal illness that can cause fever, headache, muscle pain, weakness, fatigue, diarrhoea, vomiting, stomach pain and haemorrhage (severe bleeding).

First discovered in humans in 1976 in the Democratic Republic of the Congo, the largest outbreak occurred in West Africa from 2014 to 2016, which claimed more than 11,000 lives, according to the World Health Organization.

Also Read: Ebola Increases The Number of Orphans in DRC: UNICEF

The death rate is about 50 per cent and the virus is spread by contact with contaminated body fluids, including blood and semen.

While there are no licensed treatments available for Ebola virus disease yet, multiple experimental therapies are being developed. (IANS)