Genetic make-up gives clues on past

The genetic make-up of modern humans can tell us a great deal about ancient humans and where they came from. Genetic variations can provide a glimpse into the past, according to a Trinity College researcher.

Dr Dan Bradley of the college's department of genetics delivered a public lecture yesterday at Trinity on the genetic origins of the Irish. The event was part of the Science Week Ireland programme which runs until Sunday.

Ireland was settled comparatively recently, about 9,000 years ago, Dr Bradley said. "Really, Ireland isn't that old in terms of its population." Our roots go back much further, however, to the emergence of the first modern humans in Africa about 200,000 years ago.

Geneticists studied modern DNA as a way to understand our origins but also to understand human migration. He described the work as "a more modern way of looking at the past".

Some people expressed concern about the work, suggesting it was an attempt to distinguish between peoples, but he dismissed this view.

"We are doing it to try to understand the past, not draw distinctions between present populations."

He likened the patterns of genetic variation between populations to the ripples caused when a stone hits water. You might not have seen the stone but you can see the results. "We are looking at modern ripples and trying to understand the stone that caused them."

The current genetic variability between people is very small, he told his audience. "As a species, we have quite a recent common ancestry. The differences between humans are not great."

Modern humans did not reach Asia until 60,000 years ago and Europe was populated by our kind only 35,000 years ago. Human development and diversity paralleled the development of agriculture and the domestication of animals, he explained.

Dr Bradley described his recent studies of male genetic variation and how this was matched to family name.

The analysis was dictated by surname because the family name carried information about a person's origins, he said.