Technical objections to the idea that Neanderthals interbred with the ancestors of Eurasians have been overcome, thanks to a genome analysis method described in the April 2014 issue of the Genetics Society of America’s journal GENETICS. The technique can more confidently detect the genetic signatures of interbreeding than previous approaches and will be useful for evolutionary studies of other ancient or rare DNA samples.
"Our approach can distinguish between two subtly different scenarios that could explain the genetic similarities shared by Neanderthals and modern humans from Europe and Asia," says study co-author Konrad Lohse, a population geneticist at the Univ. of Edinburgh.
If antimicrobial-resistant Salmonella is showing up in pigs, then are bacon-loving people also at risk? In his latest research, North Carolina State Univ. population health and pathobiology professor Sid Thakur looks at serotypes — or groups — of antibiotic-resistant Salmonella in people and pigs, to try to determine whether these strains are being passed from pork to people.
Sid Thakur is an expert on antimicrobial resistance in bacteria like Salmonella and Campylobacter, and how they may enter the food supply, particularly via pigs. For his latest study, he wanted to look at whether pigs and humans had the same types of antimicrobial-resistant Salmonella, which is a big public health concern. Thakur compared clinical human samples to samples he took from 30 North Carolina farms – from both the pigs and their surrounding environment, including everything from feed to floors – and found seven predominant serotypes of antimicrobial-resistant Salmonella, of which one, Salmonella Typhimurium, is also found in humans.
We’re the Only Primate Whose Teeth Shrink as Our Brain Grows
We’re the Only Primate Whose Teeth Shrink as Our Brain Grows Andalusian researchers, led by the Univ. of Granada, have discovered a curious characteristic of the members of the human lineage: Homos are the only primates where — throughout their 2.5-million year history — the size of their teeth has decreased alongside the increase in their brain size.
The key to this phenomenon, which scientists call “evolutionary paradox” could be in how the Homo’s diet has evolved. Digestion starts first in the mouth and, so, teeth are essential in breaking food down into smaller pieces. The normal scenario would be that — if the brain grows in size the body’s metabolic needs grow at the same rate — so should teeth.
In March, the health media wrote of a new link between old age and caloric restriction. We were told that hunger is healthy; scientists praise intermittent fasting; and if you eat less you’ll live longer. In short, the message was clear: eating less increases lifespan. The research that inspired these headlines used flies as study subjects, not people.
But the link between limited amounts of calories and living longer isn’t new. “I didn’t discover this, it’s a theory that’s been around since the 1930s,” said Margo Adler, the lead author of the study cited in the earlier coverage. Instead, in her paper published in BioEssays, Adler outlined a new argument as to why the well-fed appear to die young. Her hypothesis is based on data from animal studies she conducted at the Univ. of New South Wales, using Australian neriid flies. However, the longevity-hunger link she observed doesn’t translate from the lab into the real world. So, how often do lab-based experiments obscure the reality of the field? How does this affect the impact of their findings on human health?
Modern humans of European descent have a lot in common with their Neanderthal ancestors when it comes to genes related to fat breakdown in the brain. A team led by investigators from the Chinese Academy of Sciences in Shanghai has found that people of European descent have three times the number of Neanderthal-like sequences in such genes compared to other modern human populations examined. The results, published this week in Nature Communications, point to how studying ancestral sequences could help researchers better understand modern humans.
"This paper presents a sort of second-phase research using what we know about where genes have come from,” says John Hawks, a paleoanthropologist at the Univ. of Wisconsin, Madison, who was not involved in the study. “For some that come from Neanderthals, we can use that information to learn something new about human genetics and human biology.”
Human Trial Proves Stem Cells Effective for Hearts
Patients with severe ischemic heart disease and heart failure can benefit from a new treatment in which stem cells found in bone marrow are injected directly into the heart muscle, according to research presented at the American College of Cardiology’s 63rd Annual Scientific Session.
"Our results show that this stem cell treatment is safe and it improves heart function when compared to placebo," says Anders Mathiasen, research fellow in the Cardiac Catherization Lab at Rigshospitalet Univ. Hospital Copenhagen, and lead investigator of the study. "This represents an exciting development that has the potential to benefit many people who suffer from this common and deadly disease."
Scientist Developing Critical Vaccines for Humans, Pigs
Pig herds infected with porcine reproductive and respiratory syndrome can be financially devastating to farmers. The syndrome causes reproductive failure in sows and respiratory disfunction in young pigs.
Mike Zhang, a professor in the Department of Biological Systems Engineering at Virginia Tech, is researching how to develop a vaccine to combat this porcine pandemic that costs farmers as much as $560 million per year. The disease is one of the most economically devastating illnesses to the swine industry.
Scientists have discovered a previously unrecognized gene variation that makes humans have healthier blood lipid levels and reduced risk of heart attacks — a finding that opens the door to using this knowledge in testing or treatment of high cholesterol and other lipid disorders.
But even more significant is how they found the gene, which had been hiding in plain sight in previous hunts for genes that influence cardiovascular risk.
Chimpanzee Empathy Sheds Light on Human Engagement
In their latest study about empathy, Emory Univ.’s Yerkes National Primate Research Center researchers Matthew Campbell and Frans de Waal have shown chimpanzees exhibit flexibility in their empathy, just as humans do. These findings, which appear in the current issue of the Proceedings of the Royal Society B, may help explain the evolution of how and when humans engage with others and choose to offer flexibility, and how we can do more.
While it’s been long known that human empathy can extend to family, friends, strangers and even other species, it has been unknown until now whether nonhumans are similarly broad in their empathic responses. To answer this question, Campbell and de Waal used contagious yawning as a measure of involuntary empathy. According to Campbell, “Copying the facial expressions of others helps us to adopt and understand their current state.”
Researchers have discovered how Native Americans may have survived the last Ice Age after splitting from their Asian relatives 25,000 years ago.
Academics at Royal Holloway, Univ. of London and the Universities of Colorado and Utah have analyzed fossils that revealed that the ancestors of Native Americans may have set up home in a region between Siberia and Alaska which contained woody plants that they could use to make fires. The discovery breaks new ground as until now no-one had any idea of where the Native Americans spent the next 10,000 years before they appeared in Alaska and the rest of the North America.
The DNA of a baby boy who was buried in Montana more than 12,000 years ago has been recovered, and it provides new indications of the ancient roots of today’s Native American and other native peoples of the Americas.
The boy was part of the Clovis culture, which existed in North America from about 13,000 years ago to about 12,600 years ago.
Human beings are emotional creatures whose state of mind can usually be observed through their facial expressions.
A commonly held belief, first proposed by Paul Ekman, posits there are six basic emotions that are universally recognized and easily interpreted through specific facial expressions, regardless of language or culture. These are: happiness, sadness, fear, anger, surprise and disgust.
Designer Proteins Shed Light on Body’s Signal Processes
Researchers at the Univ. of Copenhagen can radically alter the properties of proteins by redesigning their chemical structure. New fundamental research based on designer proteins highlights important communication processes in the human body. In the long term, this new knowledge may lead to pharmaceuticals with fewer side effects. The findings have just been published in Nature Communications.
Proteins play a fundamental role in almost all biological processes. They consist of chains constructed of up to 20 different amino acids, and their composition, structure and function are controlled by the genetic code. Brilliant minds at the Center for Biopharmaceuticals are now attempting to rewrite the core function of proteins by making alterations in their molecular backbone, for example. By combining biological and chemical methods, researchers are able to design semi-synthetic proteins with almost no regard to the limitations of nature.
Every time you open your eyes, visual information flows into your brain, which interprets what you’re seeing. Now, for the first time, MIT neuroscientists have noninvasively mapped this flow of information in the human brain with unique accuracy, using a novel brain-scanning technique.
This technique, which combines two existing technologies, allows researchers to identify precisely both the location and timing of human brain activity. Using this new approach, the MIT researchers scanned individuals’ brains as they looked at different images and were able to pinpoint, to the millisecond, when the brain recognizes and categorizes an object, and where these processes occur.
Ancient DNA from early Iberian farmers shows that the widely held evolutionary hypothesis of calcium absorption was not the only reason Europeans evolved milk tolerance. Most of us grew up drinking milk. We were told it was the ultimate health drink. It is packed full of nutrients like calcium and other minerals, vitamins, including vitamin D, protein, fat and sugar in the form of lactose.
In the West we take milk drinking for granted because most people of European decent are able to produce the enzyme lactase in adulthood and so digest the milk sugar lactose. However, this is not the norm in much of the world, and was not the norm for our Stone Age ancestors. In fact, genetic data has shown that the ability of adults to produce the enzyme lactase has only evolved within the last ten thousand years under strong natural selection. Without this enzyme, consuming milk can lead to some unpleasant side effects like bloating, cramps, flatulence and diarrhea – a condition known as lactose intolerance.