DNA fingerprinting turns 25

Posted by liza On September - 12 - 2009

On September 11th, 1984 Alec Jeffreys, now Professor Sir Alec Jeffreys, discovered something called “genetic fingerprinting” in a laboratory in the Department of Genetics at the University of Leicester. His discovery was to become the turning point for forensic DNA analysis, paternity tests and DNA cloning.

Professor Jeffreys and his team were working on DNA patters, overwhelmed by the number of variables present even between mother and son or identical twins. “This is too complicated”, thought Jeffreys, but then came came what he calls his “eureka” moment and realized that every DNA strain contains not only the information the organism has inherited from parents, but also its unique “fingerprint” trace which repeats itself in its every single cell. What initially appeared to be a random and confusing bulk of unlinked information information, was actually the individual’s distinctive feature.

This accidental discovery opened up a new area for science, making DNA analysis crucial for criminal investigation, paternity tests and diversity analysis also among non-human species. The first real legal case involving DNA fingerprints analysis came in March 1985. A family of UK citizens originally from Ghana was accused of child swapping because the youngest one flew back to Great Britain after a trip to their hometown on a damaged passport. Blood typing analysis concluded that the boy was part of the family but couldn’t be determined if he was the son or a nephew with no residence rights. This is where Professor Alec Jeffreys got involved and scientifically proved he was a full member of the family.

Another headline-making investigation, successfully concluded thanks to Professor’s Jeffreys work, was the identification of the remains of the Nazi criminal Josef Mengele. After the Second World War he fled from the Allies and escaped to South America, where he lived for the rest of his life without ever being caught. In 1996 the German government, keen to close the case, asked professor Jeffreys together with professor Erika Hagelberg, an expert in extracting DNA from bones, to analyze the remains of Wolfgang Gerhard, a man of German origins buried in the cemetery of a small Brazilian town. The man, who drowned some years earlier in a swimming accident, was proven with a 99.94% certainty to be Mengele.

To celebrate the 25th anniversary of the discovery, the University of Leicester has organized various events and conferences to stretch once more the importance of Professor’s Jeffreys work. To read more about this, visit http://www2.le.ac.uk/departments/genetics/jeffreys/

Cloning a mammoth

Posted by liza On April - 19 - 2009

Japanese cloning experts were successful in cloning a mouse that has been dead for 15 years, and that the new animal turned out fine. It was even able to reproduce with another female rat, which gave researchers a field day, seeing how this step in science could bring forth a cloning “revolution.” The cell that the team used was stored for all these years in an environment with a constant temperature of about -20 degrees Celsius (-4 degrees Fahrenheit).

Because this temperature is almost identical to the one frozen ground has, cloning experts are confident that they can find a mammoth cell that was preserved since the last Ice Age. Such a huge breakthrough in the field of genetics has the international scientific community buzzing with excitement, as the new experiment proved that not only living animals can be cloned, but dead ones as well.

Current estimates place the potential number of dead mammoths under Siberian soil at about 10,000, so the odds of scientists finding a good cell are pretty good. The main problem for cloning the large beast is not a good cell though, but rather a host to plant the cell in. The mouse was “resurrected” when his cell was inserted into a female mouse and developed there.