Unlocking genetic secrets could change medicine

A MEDICAL revolution might be in store after the sequencing of the complete genetic codes of five southern Africans, including Archbishop Desmond Tutu and four Namibian San, !Gubi, G/aq’o, D#kgao and !A.

The results from the Southern African Genome Sequencing Project conducted in Namibia and South Africa was released in Windhoek yesterday. The study has revealed surprising results, including the fact that ‘on average, there are more genetic differences between any two Bushmen in our study than between a European and an Asian,’ said Web Miller, professor of biology and computer science at Pennsylvania State University in the United States.This finding could revolutionise the pharmaceutical industry, as it will allow scientists to develop medicines based on the unique characteristics of individuals and groups of people.Traditionally, medicines have been tested on western Europeans, proving more effective for some than for others. Now, scientists believe that armed with the genetic sequences of distinct groups they can develop effective medicines for different types of individuals and groups.Professor Stephan Schuster, one of the scientists involved in the project, said that the genetic differences make people ‘individuals,’ resulting in different responses to certain medicines. The overall goal of the genetic mapping of Southern Africans and other global groups is to eventually develop ‘personalised medicine’ and to study the effects of different drugs on a variety of groups. Professor Schuster said that genetics enables an understanding of ‘human diversity’, which even though it is slight, could mean the ‘personalisation of medicine’.The study provided a ‘means to understand the migratory patterns of a virtually forgotten sector of our global society,’ Professor Errol Holland of the University of Limpopo said yesterday. He added that the results provide ‘convincing evidence in support of a virtual cliché – the brotherhood of man’.Archbishop Desmond Tutu called the study a ‘wake-up call … we are all members of the same family’.’Can you imagine what the world could become if we accept we are all family?’ he asked.Archbishop Tutu emphasised the study’s potential to change the face of modern pharmaceutical design, and said he hoped the study would lead to a time when everyone’s genetic sequence would be available on a database to help doctors to prescribe the most effective medical treatment available.He praised the study’s findings that link the global population to their ancestors in Africa, and said that Africa is ‘home for all the people of the world. Welcome home’.The four San, all tribal elders older than 80, were the first people whose genomes have been sequenced that still practice a hunter-gatherer lifestyle, the scientists said.The results identified several genetic adaptations unique to the San, including their vulnerability to malaria and a high-fat diet. The studies furthermore show that the Southern African ‘senses are highly developed’, a trait that is helpful in a hunter-gatherer tradition. According to Professor Schuster, migration of our early ancestors from the African continent was a ‘one-way street.’ These migratory ancestors only took a part of the human gene pool with them, whereas the larger part stayed behind.This explains the genetic diversity in Southern Africa, compared to the less diverse genetic make-up of European and Asians. Even Western African genetic sequencing has shown that these groups are as diversified from their Southern African neighbours as from Europeans.Archbishop Tutu said that on a personal level the results of his genetic map have shown that he doesn’t have a genetically determined disease. The fact that the Archbishop has had polio, tuberculosis and prostrate cancer made him an ideal subject for researchers.The Archbishop said that he volunteered for the project, and was delighted with the results, adding that he wished the information had been available to him during the struggle against Apartheid.’In South Africa, where we had a hierarchy based on pigmentation – the lighter, the higher you are in the hierarchy – [this] could have been dismissed with the genetic evidence that humans are all one family.’According to Dr Vanessa M Hayes, complex diseases were badly defined before genetic mapping. Now, geneticists can examine the particulars of certain diseases thoroughly, improving the development of medicinal treatments. Professor Schuster added that for Africans, this is an opportunity to tailor make drugs for the local market, and not to have to compete on a global market.Archbishop Desmond Tutu’s lineage, including a Xhosa father and a Tswana mother, was in line with the project’s objective ‘to capture as much genetic diversity as possible,’ Dr Hayes said.The study uncovered 1,3 million new markers never before identified in a genetic sequence. These markers are the backdrop of phase two of the project, in which a wider variety of Southern African genomes will be studied.The ‘sequencing revolution’ will, according to Professor Schuster, decrease the costs of mapping genetic sequences, and in future, it ‘will become viable to know the sequences of everyone’.