Bulletin Spring‧Summer Autumn‧Winter 1999

The University and the Hong Kong Government Join Hands in the Development of DNA Fingerprinting in Hong Kong DNA fingerprinting is a new identification technique originally proposed by Ale c Jeffreys o f the University of Leicester in 1985. Although this method has gained wide popularity among law enforcement agencies in the United Kingdom and the United States, it is still relatively new in Asia. DNA fingerprinting as its name implies is a procedure which enables experts to examine a particular person's genetic blueprint, namely his DNA, and obtain a pattern which uniquely belongs to him or her. In short, it is a fingerprint at the molecular level, and it is so unique to an individua l that an expert can identify him from among a million or even a billion people. In order to carry out this procedure, all that is needed is a sample of the individual's biological material, either a blood stain or a few hair roots. Compared with existing forensic techniques, DNA fingerprinting offers a resolution hundreds to thousands times more sensitive an d discriminating. In early 1989 ， the Forensic Laboratory of the Hong Kong Government approached the University's Biotechnology Laboratory to undertake a joint project on introducing the technology of DNA fingerprinting to Hong Kong. This proposal capitalized on the Biotechnology Laboratory's expertise in molecular biology and the Forensic Laboratory's experience in handling forensic samples. To star t the project off, a three-day workshop on DN A fingerprinting, sponsored by Amersham International PLC, was held on campus between 25th and 31st May 1989. The workshop was attended by representative s from Hong Kong, Taiwan and Singapore. Although the procedure of performing DNA fingerprinting is well established, its introduction in Hong Kong requires validation at severa l levels. There were three primary objectives in the join t venture: (1) to work out a standard protocol for DNA fingerprinting so that it can be performed faultlessly on a routine basis; (2) to evaluate the best set of restriction enzymes and probes for use in Hong Kong; (3) to obtain information on DNA profiles of the general population of Hong Kong in order to accurately calculate the allele frequency*. Funds for this project have been provided by the government's Science and Technology Committee. To date, with the help of the University's Biotechnolog Laboratory, a protocol has been worked out for routine use, and preliminary data on the DNA profile of over 150 individuals have been gathered. The foundation for a new technology to fight crime in Hong Kong has thus been laid. Th e Hong Kong government w i l l take further steps necessary to institutionalize the procedure in the courts o f law in Hong Kong, probably in 1991. * An allele is the variation in the DNA sequence occupying a given chromosomal locus. Within a population, a given allele will occur at a certain frequency, which is allele frequency. These frequencies change from population to population. What is DNA Fingerprinting? By Dr. Walter K.K. Ho ， Department of Biochemistry DNA (deoxyribonucleic acid) is located in the chromosomes of our cells and is a long chain-like structure with a sugar phosphate backbone carrying pairs of molecules called bases along its length. There are four types of bases and they form pairs with one another. In the human DNA, there are more than a billion of these base pairs and their sequence constitutes our genetic code. Wha t makes two persons alike or different can be attributed t o the sequence of base pairs in their DNA. Within our genetic makeup, there are genes which w i ll code for essential functions which are the same for all humans (e.g., genes for the formation o f the human eyes), and any variation in their DNA sequences w i l l mean abnormalities and diseases. However, within this framework , there are other genes S C I E N CE & ME D I C I NE 1 2 -