Aug 28 : Danish researchers from the University of Copenhagen have discovered DNA from living bacteria that are more than half a million years old.

Before this, traces of still living organisms has not been found.

According to Prof. Eske Willerslev, the exceptional discovery can lead to a better understanding of the ageing of cells and might even cast light on the question of life on Mars.

“Our results show that the best way to survive for a long time is to keep up metabolic activity. Doing this allows for continuous DNA repair,” said Prof. Willerslev, lead author of the study in the current issue of the Proceedings of The National Academy of Sciences (PNAS).

“The work suggests that if bacterial life existed on Mars or on Jupiter’s moon Europa, it might still survive locked in icy soils,” he said.

Prof. Willerslev and his team discovered ancient bacteria that still contain active and living DNA during excavations of layers of permafrost in north-western Canada, the north-eastern Siberia and Antarctica.

Prof. Willerslev said the team also found out a method that makes it possible to extract and isolate DNA traces from cells that are still active.

“It gives a more precise picture of the past life and the evolution towards the present because we are dealing with cells that still have a metabolistic function – unlike dead cells where that function has ceased,” said Prof. Wilerslev.

He, however, admitted that there is a very long way towards understanding why some cells become that old.

“But it is interesting in this context to look at how cells break down and are restored and thus are kept over a very long period. Our methods and results can be used to determine if there was ever life on Mars the way we perceive life on earth,” said Prof. Wilerslev.

“And then there is the grand perspective in relation to Darwin’s evolution theory. It predicts that life never returns to the same genetic level. But our findings allows us to post the question: are we dealing with a circular evolution where development, so to speak, bites its own tail if and when ancient DNA are mixed with new,” he said. (ANI)