SCIENTISTS HAVE sequenced the complete genetic code of an Irish person for the first time. The 3.1 billion sub-units of DNA that comprise the human genome were mapped by a team from the Conway Institute at University College Dublin, using advanced sequencing technology.
The landmark study, due to be published in the online journal Genome Biology, provides the first complete genetic picture of the Irish branch of the European ancestral tree.
Scientists are reading the genomes of many species to understand how life forms differ from each other, and why they become diseased. Unravelling the differences between the Irish genome and other population groups may yield vital clues as to why Irish people are more susceptible to certain diseases, such as cystic fibrosis.
The UCD team, led by professor of comparative genomics Brendan Loftus, used DNA from an anonymous Irish male with a confirmed Irish ancestry of three generations.
Prof Loftus said the choice of individual to sequence was also made on the basis of prior genetic work with this individual that “showed variation typical of the island”.
“We have a better chance of understanding disease biology and susceptibility if we can stratify different populations on the basis of their genes,” he said.
The study uncovered some three million genetic variants in the Irish genome compared to a reference genome. Though most of the variation has been seen in other population groups, some 13 per cent, corresponding to about 300,000 variations in genome steps, had not been recorded before.
The big question is how much of this variation is specific to the individual and how much is representative of an “Irish genetic signature”, said Prof Loftus.
His team has already made one important discovery, identifying a variation in the sequence that disrupts a gene associated with inflammatory bowel disease, which affects about 15,000 people in Ireland.
The first full sequence of human DNA was published in the US in 2003, after some 13 years of research, costing $2.7 billion. The six-man UCD team took little over a year to sequence the first complete Irish human genome, at a cost of €30,000.
