Human genome shows DNA differences - revised DNA map

DNA :: Human genome shows DNA differences - revised DNA map

Humans are genetically more diverse and the repercussions could be far-reaching for medical diagnosis, new drugs and the tale of human evolution itself, a new research, published in the British journal Nature, suggests. Scientists have shown that our genetic code varies between individuals far more than was previously thought.

A US-led team made a detailed analysis of the DNA found in 270 people and identified vast stretches in their codes to be duplicated or even missing.

In 2000, the Human Genome Project unveiled a road map of the six billion chemical bases, or alphabet molecules, that make up the body's genetic structure called DNA.

The DNA encodes for 30,000 genes or proteins which are responsible for every physical characteristic in the body, including eye and hair color. At the time, scientists said all humans could be 99.9 percent genetically identical.

But as they peered more deeply into the DNA of unrelated individuals, researchers made a startling discovery - large segments of their DNA, from thousands to millions of units, varied greatly, a phenomenon called copy number variations, or CNVs.

The new understanding will change the way in which scientists search for genes involved in disease.

Scientists are not sure why the copy variations emerge, but it probably has something to do with the shuffling of genetic material that occurs in the production of eggs and sperm; the process is prone to errors.

As well as aiding the investigation of disease and the development of new drugs, the research will also inform the study of human evolution, which probes genetic variation in modern populations for what it can say about their relationship to ancestral peoples.

This new study is based on two technical breakthroughs: one in faster, accurate sequencing of DNA and the other in a powerful software programme to spot the CNVs.