Study: Northerners Are Hot Stuff

(AP)  People native to the far north evolved to produce more heat in their cells, a new study says. The researchers suggest this change is a climate-driven effect.

The change occurs in the mitochondria, the parts of human cells that burn fuel to produce heat and energy, according to the team of researchers led by Eduardo Ruiz-Pesini of the University of California at Irvine.

The scientists analyzed mitochondria from 1,125 people ranging from Africa to Europe and Arctic Siberia. They found that that mutations in mitochondria DNA, increasing production of heat, though reducing energy production, rise in people living closer to the pole, compared to tropical residents.

The change results in an increase propensity for energy deficiency diseases, but also in increased longevity and resistance to aging, they report in Friday's edition of the journal Science.

"Our observations support the hypothesis that certain (mitochondrial DBA) variants permitted humans to adapt to colder climates," the researchers concluded.

The variants continue to produce differences in energy production and affect health, they said.

DNA provides the blueprint for the development of the body, combining information from the separate DNA of each parent. However, mitochondrial DNA directing the energy production in cells is inherited only from the mother, unlike the DNA that provides the body's primary set of instructions for operation.