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The Wellcome Trust completes a genetic scan of 4000 TEDS twins

In the 2009 newsletter we told you about the prestigious Wellcome Trust project that has been using the cheek-swab DNA you provided and the latest technology to look at millions of DNA markers across the genomes of 4000 TEDS twins. The laboratory work involved in the first stage of the project has been carried out at the Wellcome Trust Sanger Institute near Cambridge.

In the lab, each of the 4000 TEDS twins was assigned their own GeneChip. A GeneChip is a silicon wafer smaller than a postage stamp; it’s similar to a computer chip, but each one is covered with a carpet made up of billions of short strands of DNA. The chips were processed in batches. For each batch, the cheek-swab DNA was added to the GeneChips and the chips were incubated in a low oven overnight. During the night a chemical reaction took place as the cheek-swab DNA attached itself to the DNA carpet on the chip. In the morning, a computer-driven laser read off the combination of DNA variants, just like the laser in a DVD player, and the genetic information was stored in computerised form. Earlier this year, the Sanger Institute finished working their way through all 4000 twins and the first stage of the lab work was complete.

Now we have the electronic catalogue of DNA variants for each person, we have begun the task of analysing the data to try to identify the sections of the human genome that influence all the different things TEDS was set up to study. As you can imagine, the genome-wide information from 4000 twins is a vast amount of data, so we need something more than a pocket calculator for the analysis. In fact, if we did try to use a calculator and entered one value per second, it would take us almost one hundred years to enter the three billion numbers involved in the first stage of the analysis. Luckily, we are instead using one of King’s College London’s supercomputers to crunch the numbers, so we’ll be seeing some results way before next century! We’ll be publishing the first of these studies this year and we’ll bring you the findings here on the website, and in the next edition of the TEDS newsletter.