When a single genetic mutation first let ancient Europeans drink milk, it set the stage for a continental upheaval. During the most recent ice age, milk was essentially a toxin to adults because — unlike children — they could not produce the lactase enzyme required to break down lactose, the main sugar in milk. But as farming started to replace hunting and gathering in the Middle East around 11,000 years ago, cattle herders learned how to reduce lactose in dairy products to tolerable levels by fermenting milk to make cheese or yogurt. Several thousand years later, a genetic mutation spread through Europe that gave people the ability to produce lactase — and drink milk — throughout their lives.
Young children almost universally produce lactase and can digest the lactose in their mother's milk. But as they mature, most switch off the lactase gene. Only 35% of the human population can digest lactose beyond the age of about seven or eight (2). “If you're lactose intolerant and you drink half a pint of milk, you're going to be really ill.
Most people who retain the ability to digest milk can trace their ancestry to Europe, where the trait seems to be linked to a single nucleotide in which the DNA base cytosine changed to thymine in a genomic region not far from the lactase gene. There are other pockets of lactase persistence in West Africa (see Nature 444, 994–996; 2006), the Middle East and south Asia that seem to be linked to separate mutations3 (so called 'Lactase hotspots').
The single-nucleotide switch in Europe happened relatively recently. Thomas and his colleagues estimated the timing by looking at genetic variations in modern populations and running computer simulations of how the related genetic mutation might have spread through ancient populations4. They proposed that the trait of lactase persistence, dubbed the LP allele, emerged about 7,500 years ago in the broad, fertile plains of Hungary.
Carrie Underwood, who recently signed on as the newest Global Brand Ambassador for Almay, is taking fans behind the scenes of her first Almay campaign. “I love makeup. I always have,” she says in the clip.
New research suggests a surprising degree of similarity in the organization of regions of the brain that control language and complex thought processes in humans and monkeys. The study also revealed some key differences. The findings may provide valuable insights into the evolutionary processes that established our ties to other primates but also made us distinctly human.
The research concerns the ventrolateral frontal cortex, a region of the brain known for more than 150 years to be important for cognitive processes including language, cognitive flexibility, and decision-making. "It has been argued that to develop these abilities, humans had to evolve a completely new neural apparatus; however others have suggested precursors to these specialized brain systems might have existed in other primates," explains lead author Dr. Franz-Xaver Neubert of the University of Oxford, in the UK.
By using non-invasive MRI techniques in 25 people and 25 macaques, Dr. Neubert and his team compared ventrolateral frontal cortex connectivity and architecture in humans and monkeys. The investigators were surprised to find many similarities in the connectivity of these regions. This suggests that some uniquely human cognitive traits may rely on an evolutionarily conserved neural apparatus that initially supported different functions. Additional research may reveal how slight changes in connectivity accompanied or facilitated the development of distinctly human abilities.
The researchers also noted some key differences between monkeys and humans. For example, ventrolateral frontal cortex circuits in the two species differ in the way that they interact with brain areas involved with hearing.
"This could explain why monkeys perform very poorly in some auditory tasks and might suggest that we humans use auditory information in a different way when making decisions and selecting actions," says Dr. Neubert.
A region in the human ventrolateral frontal cortex -- called the lateral frontal pole -- does not seem to have an equivalent area in the monkey. This area is involved with strategic planning, decision-making, and multi-tasking abilities.
Editor's Note: We've always held that content curation (with added insight and value) is great for SEO. The below infographic (courtesy of TechMagnate and Beth Kanter) lays out some of the benefits of content curation.
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