Genetic map of Europe shows differences between populations
Scientists at the Erasmus University Medical Center in the Netherlands have developed a genetic map of Europe that shows the degree of genetic relatedness between populations. While all European populations are genetically quite similar, enough differences exist to make it possible to develop a forensic test that could determine from which European country an individual originates.
The major genetic differences exist between the northern and southern populations. The geographic pattern of genetic differences likely reflects the results of three ancient migrations of humans from the south and Near East, according to the study. The map also outlines two genetic barriers within the continent. The first separates Finland from the rest of Europe because the Finnish population expanded from a very small base. The other separates the Italians, likely because the Alps hindered migration between Italy and the rest of Europe.
The study tested 300,000 sites of common genetic variation on almost 2,500 people. Analyzing these sites of genetic variation requires more genetic material than is available in most forensic samples, so scientists are currently searching for sites with the highest diagnostic ability for European origin. Of the 100 strongest sites, 17 are found in the region that enables humans to tolerate lactose – a trait that originated in cattle herders of northern Europe 5,000 years ago. (Source: nytimes.com)
Caffeine myths debunked
The Center for Science in the Public Interest published a review of numerous scientific reports outlining myths and facts about coffee.
Caffeine has long been thought to be a strong diuretic, but studies last year revealed that people who drink up to 550 milligrams of caffeine do not produce any more urine than those drinking caffeine-free beverages. A Starbucks grande coffee contains only 330 milligrams of caffeine and therefore would not speed up urine production. Anything over 575 milligrams is considered to have diuretic effects.
Contrary to the popular belief that caffeine increases the risk of heart disease, researchers at UC San Francisco concluded that daily coffee drinkers do not have a higher risk of heart disease. While caffeine does, however, cause a small temporary rise in blood pressure, it does not contribute to hypertension in the long-term.
A 1981 Harvard study sent panic throughout the coffee-drinking world when it claimed caffeine was linked to pancreatic cancer, but it appears now that smoking was the culprit in that study. An international review of 66 studies last year confirmed that coffee drinking has little to no effect on the development of kidney or pancreatic cancer. Another study even found that coffee drinkers have half the risk of getting liver cancer. (Source: nytimes.com).
Science Scene is compiled by ALYSOUN BONDE. She can be reached at campus@californiaaggie.com
