Emirati genome mapping quest awaits approval

The search is on for 100 candidates to participate in a programme that will determine the genetic makeup of Emiratis.

It is essential to establish genetic benchmarks before the Emirati gene pool becomes too diverse, says Dr Ghazi Omar Tadmouri, the assistant director at the Centre for Arab Genomic Studies.

Scientists will map the genomes of at least 100 Emirati volunteers in a groundbreaking study that will help the prevention, diagnosis and cure of hereditary diseases.

Experts at the Centre for Arab Genomic Research (Cags) will be looking for individuals with no history of serious illnesses. Samples of their DNA will be used to create a "reference template", which will be used as a benchmark when evaluating other people with variant genes.

"A sample size of 100 may sound small, but in reality it is large," said Mahmoud Al Ali, the director of Cags. "We have to go into the history of each individual and their families. There is also the issue of ethnicity, which is quite diverse. Good sampling means that we cover many ethnicities and the reality of the situation."

The centre is in the process of submitting documents for ethical approval by the Ministry of Health. Approval is expected in about two weeks and sample collection will begin after Eid Al Adha.

Dr Ghazi Omar Tadmouri, the assistant director at Cags, said choosing the most accurate samples required a collective effort.

"You need the help of many people, including historians, people who deal with demographics, and population geneticists, so that they are able to decide which sample to select from every emirate," he said.

The sample collection could take from several months to a year, Dr Tadmouri said. Samples will be taken in the form of blood, but DNA can also be obtained from a cheek swab or a strand of hair.

The second phase, the recording of the data, takes a couple of weeks and the final phase, the analysis and annotation of the data, is an ongoing process.

The raw genetic make-up of a single individual takes about three terabytes of hard disk space, Dr Tadmouri said. For 100 samples, this is the equivalent of more than 600 laptops filled with data. However, only 10 per cent of the genetic coding actually useful.

"The remaining part is inter-gene space, mainly for support or genes that are no longer functional," Dr Tadmouri said.

There are about 5 billion differences between the genetic code of one person and another. However, the Emirati gene samples are expected to show a strong resemblance to one another.

"We're expecting only a diversity of 5 per cent in the genes among the Emiratis," Dr Al Ali said. "This could be attributed to several factors; one could be the intertribal marriage within the Emirati community. The environment is a very crucial factor when looking at the genetic make-up of people from a particular region."

The results from the mapping will be used towards the prevention, diagnosis and cure of various diseases.

"Instead of dealing with a disease only when it appears, we can decide on the susceptibilities of the disease for that individual and modify the lifestyle before it happens," Dr Tadmouri said. "That information is available the moment a person is born, so why wait."

In the UAE, it is estimated that nearly 70 per cent of diseases affecting nationals are genetic.

In 2003, the international human genome project was completed on eight masked samples of unknown origin, from which a reference map was drawn.

"The [sample size] is very little to represent humanity," Dr Tadmouri said. "Although it's a very important landmark, that reference map will never be representative of the whole world."

By benchmarking local maps with those that are not representative of the country's normal population, scientists c be missing out on important variations.

One such example of this is thalassaemia. Alpha-thalassaemia, which usually results in the death of children in utero or at birth, is the product of a gene defect that is estimated to be carried by nearly half of all Emiratis. Meanwhile beta-thalassaemia effects about 8 per cent of the population. The world average does not exceed 3 per cent, Dr Tadmouri said.

"Every population has between three to seven common mutations for this disease," he said. "But when you come to the Arab world, especially in the UAE among the nationals, you will have an array of 30 mutations."

Dr Tadmouri attributed such variations in the region to diversity.

"This region was exposed to lots of intermingling between different populations that settled or passed by the area," he said. "Each population left their genetic contribution causing a 'cosmopolitan' gene pool."

Now is the ideal time to start the mapping process, Dr Tadmouri said, before the gene pool becomes too diverse to pinpoint genetic trends in specific populations.

"With advanced technology allowing us to travel and intermarriage, the population is getting mixed. This is not good for science as it makes it very difficult to resolve anything," he said. "We need to get a snapshot of the immediate past before this picture gets lost forever."