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Photo of Kari Stefansson Iceland Genes -- Kari Stefansson

DeCode Genetics studies the unique genetic heritage of Iceland's population. What makes Icelanders unique -- and what does the company hope to find? To learn more, read answers about this topic from deCode Genetics president, Kari Stefansson.

Q Everybody we saw on the video seemed to have blond hair and blue eyes. Is that a genetic trait in Iceland -- or just a coincidence?

The answer is no and no. The blond hair and the blue eyes are not a trait (characteristic) conferred upon people by one gene. They are two traits that cosegregate. It is, however, no coincidence that these two traits cosegregate in the Icelandic population. The genes that lead to blond hair on one hand and blue eyes on the other are sufficiently common in Icelanders that they coincide in large proportion of the population. It's not a coincidence that these genes are common in Icelanders. They are common because large proportion of the settlers of Iceland were blond with blue eyes.

Another way to look at this is to say that blue eyes and blond hair is a polygenic trait like diabetes or asthma. Polygenic trait is a characteristic that requires the confluence of alleles or mutations of more than one gene.

Q What interested you in choosing your profession as a genetic researcher?

Human genetics is the discipline that studies how the information that goes into making a man is passed from one generation to the next. This information is written in DNA that contains clues to how both our strengths and our weaknesses can be explained. Hence, genetics provides a marvelous opportunity to study diseases. I am first and foremost a physician, concerned with how to cure and prevent diseases. I am secondly a scientist trying to find an explanation to diseases, in the hope that it will lead to new ways to treat and prevent diseases. I am convinced that genetics provides the best tools to discover the nature of human diseases and new ways to treat and prevent them. These are the reasons I became a geneticist.

Q The relative isolation of Icelanders creates an advantage for this genetic research -- but does being part of this homogeneous population pose any specific genetic disadvantages or health risks for them today?

The question here is whether the genetic homogeneity of Icelanders poses a threat to the population. One way in which it could do so is by subjecting Icelanders to an increased risk of recessive diseases (diseases that require that there is a mutation in both the gene from the mother and the father). The fact of the matter is that the prevalence of recessive diseases in Iceland is not greater than among the large heterogeneous nations.

The prevalence of the common diseases such as hypertension, diabetes and schizophrenia are also approximately the same in Iceland as among the heterogeneous nations, which tells us that when it comes to these diseases the founders of Iceland must have been rather average.

One way to rephrase this question would be to ask whether there is a high price to pay for the consanguinity that comes with the genetic homogeneity of a small, marginal population. The answer is probably no. It appears that the beneficial effects of the consanguinity balance out the negative effects.

Q With so many diseases still uncured, how does a company like yours decide which disease-causing genes to search for first?

The diseases that are still unsolved are many and it is difficult to give a satisfactory answer when we are asked why we are working on one disease rather than another. The truth of the matter is that there are many factors that figure into our decision including our own interest at the moment when the choice needs to be made, our ability to raise money to do the work, and pressure from patient groups and health care workers. We would love to have an opportunity to work on all diseases of man -- and perhaps we will!


Scientific American Frontiers
Fall 1990 to Spring 2000
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