DNA typing at your fingertips
New outfit offers state- of- the- art testing for paternity or crime detection

Detecting diseases early
DNA typing is also an invaluable tool not
only in fighting infectious diseases such as dengue, TB and hepatitis but also in the early detection of genetic disorders such as thalassaemia .

If the clinical symptoms of dengue are present, a molecular diagnosis can be done through DNA typing to check for the virus within the first three days, unlike the usual blood tests which need to be taken only after the sixth day, says Dr. Gunasekera.

"Take the case of thalassaemia. We can check whether a person is a carrier by doing this test. Even in the cases where cancer runs in the family, we can do DNA typing to check out whether a healthy person is genetically pre-disposed to getting the disease," adds Dr. Fernandopulle.

By Kumudini Hettiarachchi
The only person who is certain of a child's
father is his mother, is an oft-mentioned
derogatory joke against women.

Frivolity apart, that scenario has changed forever. Now even a man can establish for certain whether he is the father or not, thanks to DNA typing.

And DNA typing has well and truly been established in Sri Lanka through the pioneering and trailblazing efforts of a few scientists who included Dr. Maya Gunasekera and Dr. Neil Fernandopulle.

To throw open and make bio-technology accessible to the wider public Dr. Gunasekera and Dr. Fernandopulle have set up Genetech, Sri Lanka's first biotech company, a private facility offering DNA typing services.

" Molecular biology lies at the interface between genetics and biochemistry. It is an exciting and rapidly growing area of science. Genetech Molecular Diagnostics and School of Genetech Technology seeks to introduce to Sri Lanka these benefits," says Dr. Gunasekera who is the Chief Executive, citing the example of how DNA typing was used a few years ago to allay the fears of a father about the paternity of his 13-year-old daughter. "All parties concerned, especially the daughter, were relieved to find that he was in fact the father."

DNA typing is used to identify individuals from biological samples. This is mainly done in forensic casework where it is possible to determine the identity of a criminal by typing the DNA left behind at the scene of the crime. The second important use of DNA typing is to determine family relationships such as paternity or maternity and even in the identification of mutilated bodies, explains Dr. Gunasekera.

Though DNA fingerprinting was discovered in 1986, with DNA typing following in the 1990s, it came to Sri Lanka only with tests being done for the first time in the infamous Hokandara murder case in 1996. Dr. Gunasekera who was part of the team at the University of Colombo's Science Faculty, which was involved in this pioneering effort used this near miraculous technique to test the DNA of one of the victims whose bloodstains had been found on the clothing of three of the accused.

DNA (deoxyribonucleic acid) is self-replicating material present in all living organisms. It is inherited from our parents and is considered the chemical blueprint that makes us unique, except in the case of identical twins and now in clones. A child inherits one half of his or her DNA from the mother and the other half from the father.

DNA encodes all the genetic information of an individual and is found in almost every cell in the human body. It does not change throughout a person's life and can be found in skin cells, muscle tissue, blood, hair follicles, saliva, semen, teeth, bones and even in tiny nail scrapings.

DNA is a constituent of chromosomes which are thread-like structures found in the cell nucleus and carry genetic information in the form of genes.

Considered even better proof than fingerprinting, DNA typing has been used in the west due to its 100% success rate in crime-busting.

Usually, the 'short-tandem-repeat' (STR) method is used to analyse DNA samples. This method identifies subjects not by the entire genetic blueprint but by tiny stretches of DNA coding known as short tandem repeats. These STRs are just two to seven base pairs long and give accurate results.

The chances of two people having the same DNA profile at three genetic locations would be about one in 2000; at nine locations one in a billion and at 12 locations one in at trillion.

DNA typing in Sri Lanka began as an award-winning Ph.D project of Dr. Fernandopulle in 1997 with Dr. Maya Gunasekera and Dr. Nalin Gunasekera as investigators at the Colombo University.

By 1999 they were in a position to offer DNA typing for judicial cases and that's when it was used in the Hokandara murders, where six in one family were murdered.

Later Dr. Maya had moved onto the Ragama medical faculty and seeing the demand of this kind of specialized service and feeling constrained in providing them within a university environment had decided to mobilize the expertise of 12 professionals and set up Genetech in Borella. Registered in May 2002, Genetech had accepted the first sample in a paternity case in October.

The official inauguration of Genetech took place yesterday at the SLFI.

" In November we did DNA typing in a rape-murder of a child, with two more similar cases coming in December," says Dr. Fernandopulle voicing concern over the incidents of rape-murder involving children.

Genetech undertakes DNA typing services for a fee of Rs. 9,000 in cases ranging from child custody and maintenance to rape and murder and even in adultery or testamentary cases.

DNA typing is also a boon to the innocent. " When we were at the university a man who was accused of making his daughter pregnant was proved otherwise while in another case a school van driver who was suspected of making a 12-year-old pregnant, when tested was found not to be the culprit," says Dr. Fernandopulle.

Back to Top  Back to Plus  

Copyright © 2001 Wijeya Newspapers Ltd. All rights reserved.