© AP Photo / Yahya AhmedThis Iraqi family can point to social and cultural factors that define them as an Iraqi, but a genome mapping programme will try to get to the bottom of the genetic factors in the Arab identity
One hundred people who describe themselves as Arabs - half of them originating on the Arabian peninsula and the rest from the wider Arabic nations including Egypt, Syria and the Maghreb - will have their entire genetic makeup sequenced by the Arab Genome Project.
Last month, an anonymous tribal figure from Saudi Arabia became the first Arab to have his genome sequenced by a consortium of researchers with Saudi Biosciences, the Danish firm CLC Bio and the Beijing Genomics Institute. They want the other 99 to be sequenced by the end of 2010 and the results to be publicly available.
David MacArthur, an Australian researcher who runs the science blog Genetic Future, said the Arab genome project stands out from what the increasingly commonplace announcements in genome research focus on.
"Middle Eastern populations represent an extremely attractive target for human geneticists: there is both a high level of genetic diversity due to the location of the Middle East at the nexus of Africa, Europe and Asia and a disproportionately high level of genetic disease, at least partly due to the prevalence of first cousin marriages," he wrote last month.
"The levels of genetic disease will provide plenty of fodder for rare disease gene hunters, and the genetic diversity may help to narrow down causative variants for some common diseases."
A secondary factor he identified is that as the Gulf countries look to a post-oil economic future, the burgeoning field of genetics provides the opportunity to turn the region into a centre of excellence in that field in the same way that Singapore has become a world hub for biomedicine - and with some distinctly local benefits.
Dubai has already become the home of the Centre for Arab Genomic Studies, established five years ago by the Sheikh Hamdan Bin Rashid Al Maktoum award for medical sciences. Within three years, the leading science journal Nature cited the centre for its potential to "bring practical health benefits to the states of the eastern Mediterranean".
"It is the diverse people across this geographical area who present one of the greatest opportunities for the application of medical genetics," the journal said in an editorial.
"The 23 member states of the Arab League are bound by the aim of cooperation for the health of their peoples, who comprise over 323 million from Mauritania to Oman. There now exists the declared intent, the human capital and the financial potential for considerably greater investment in research and development across the entire region. In addition, some 30 million people worldwide can trace their ancestry to this region."
The health benefit flows directly from the unique genetic and social aspects of the population that attract the interest of geneticists. As The National reported on Oct 10, Nature cited research that second cousin marriages happened in between 20 and 70 per cent of nuptials. The human face of this consanguinity - the sharing of common ancestors - comes in the form of an overrepresentation of noncommunicable illness, such as diabetes. The UAE has three times as many diabetics as the world average.
One of the benefits of analysing the genomes found among the Arabian population is it could also help resolve the conflict over whether the origin of those diseases is primarily genetic or social, as traditionally nomadic people suddenly change within living memory from a roaming lifestyle with a diet of complex carbohydrates to being far more sedentary and eating fattier processed food that comes with adopting the ways of the developed world.
Nature takes the view that social factors are likely to be greater determinants than the genetic ones.
"It is unlikely that consanguinity contributes significantly to polygenic or multifactorial diseases once socioeconomic variables have been controlled for," it said.
"However, in light of the high, and increasing, prevalence of cardiovascular diseases and diabetes with economic development in the region, it is important to consider the genetic component of common and complex diseases.
"The existence of diverse highly localised populations suggests that genetic characterisation of a range of populations within the region would be particularly rewarding in this respect. Indeed, in much of the rest of the world it is very hard to make sense of population structure because of migration, admixture or lack of historical records.
"The Arab world, possessing its own funding sources, geneticists and particular populations, is well placed to be a leader in demonstrating the type of cooperation between resource-rich and less well resourced countries that will characterize the next phase of human genomics."
When Saeed al-Turki, the coordinator of the Arab Human Genome Project, announced the completion of the first sequencing last month, he highlighted the possible health spinoffs from the 500 million Saudi riyal (Dh489m) project.
"The advantage of the project is that it studies the differences between peoples, and that will explain the spread of specific illnesses such as diabetes, heart diseases etc," he said.
"Twenty-five percent of the Saudi population has, or is liable to have, diabetes and that will form a big burden on health services."
With a better understanding of the causes of the illnesses comes the prospect of a targeted medical response.
The head of the board of directors at Saudi Biosciences, Prince Ahmad bin Sultan bin Abdulaziz, said at the time of the sequencing of the first Arab's genome that it was "the first milestone in our goal to pioneer the personalised medicine era in the Arab world".
"The Arab world was never an active participant in the large international projects in the field of genomics, and we believe that should change," he said.
One of the goals of modern medicine is to use individual genetic composition to tailor cures to a specific patient. For personalised medicine to work, human genetic variation has to be mapped accurately and that has only recently been available in a fast and affordable manner by the latest technological advances in the field.
Because most of the genome work to date has been on European, Asian and African populations, there was the prospect that Arabs might miss out on the breakthrough thought to be looming in specialised medicine.
Besides the possible health benefits, the study could also help provide clues to ancient migration such as the Semitic migration from Africa to the Arabian peninsula. Genome sequencing has already caused some previously settled scientific theories to be rewritten, with the famously well-travelled Polynesians now being traced back to the aboriginal hill tribes now found in Taiwan.
The Arab Human Genome Project is part of a much larger undertaking dubbed the 1,000 Genomes Project. This vast programme, launched in January of this year, involves teams of researchers across the globe taking advantage of the advent of cheaper and faster sequencing technology to create the most detailed catalogue of human genetic variation ever compiled. One-tenth of the catalogue's content is expected to come from the Arab researchers participating in its local manifestation.
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