WORLD DNA Day is celebrated every year on April 25 to honour the achievement of the Human Genome Project (HGP), which was completed in April 2003, and the ground-breaking elucidation of the model structure of DNA double helix which was published in Nature magazine on April 25,1953. After the US Congress passed a resolution designating April 25 as DNA Day, the National Human Genome Research Institute began celebrating the day.

The HGP was an international project aimed at discovering the sequence of human DNA and defining all genes that are found in the human genome. The HGP played a big role in explaining the genetics of humans and helped us understand a variety of fundamental questions, including the total number of genes that we have, how our cells function, how diseases develop and what actually happens when we become sick.

The HGP improved biology and medicine because establishing the human genome sequence led to the designing of high-throughput sequencing technologies, and encouraged scientists, doctors and the community to discuss the ethical and social problems raised by such technologies.

Facts discovered about our DNA are quite amazing. For instance, siblings with the same mother and father, except identical twins, share 50% of their DNA. Uncle-nephew or aunt-nephew/niece share 25% of their DNA while cousins share 12.5%. When the HGP was completed, it was found that humans contain approximately 25,000 genes. These genes differ in size from a few hundred DNA bases to over two million bases. Each individual inherits two copies of each gene, one from each parent. Humans are 99.9% genetically similar and it is the 0.1% difference that makes each of us unique.

One of the biggest beneficiaries of the HGP is the field of medicine. Data from a patient's genetic profile may assist doctors in selecting the appropriate drug or treatment and administering it at the appropriate dose or regimen. This new approached in healthcare is called personalised or precision medicine. Every day, new genetic data is being profiled and used to improve the implementation of personalised medicine. As more DNA data is understood, personalised medicine may soon become routine and a part of mainstream medicine.

Besides blood, DNA can be extracted from skin, saliva, amniotic fluid and other tissues. These specimens can be studied in a genetic lab for variations in genes, DNA or proteins. Services for such genetic testing are now available online. Many companies are now offering direct to consumer genetic testing which offers the public genetic tests without having to go through a medical doctor.

Anyone can now order a genetic test by contacting these companies which will then send test kits that provide manuals and tools for extracting a saliva sample or a buccal smear that contains DNA in the comfort of their home. The specimen can then be delivered to a laboratory where the search for unique variations in genes or DNA is carried out.

While such direct to consumer genetic testing has helped many people to know more about their DNA, it must be understood that genetic data analysis is complicated and contextual reliant, and the results can yield false positive and false negative outcomes.

Anyone who is worried about the outcome of a direct to consumer genetic test should ask for guidance from a certified clinical geneticist or a genetic counsellor. The public should understand that these new technologies and approaches are intended to assist clinicians and they are not without their limitations and shortcomings.

Geneticists, health professionals, educators and the general public should join hands in the effort to study our DNA and appreciate current developments in genetic research that contribute to advances that affect our lives.

PROF ZILFALIL ALWI

Head, Malaysian Node of the Human Variome Project (MyHVP) & President, Malaysian Society of Human Genetics (MSHG)

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Appreciating genetic research that affects our lives - The Star Online