Researchers from the Queensland Institute of Medical Research (QIMR) are a step closer to understanding the heritability of complex diseases.
By studying the genes and height of almost 4,000 Australians, researchers have discovered that it is the cumulative effect of lots of small genetic variations in many of our genes that determine our height.
According to lead researcher Professor Peter Visscher from QIMR’s Queensland Statistical Genetics Laboratory, “This finding helps us understand the underlying genetic architecture and can be applied to many other complex traits such as common diseases.”
“We know from family studies there is high heritability of these complex traits however, we could not fully account for the variation by studying common genetic changes. We were beginning to think that very rare mutations must play an important role. The question we wanted to answer was where is the missing heritability – the so-called dark matter of the genome?
“What we found was that many of the gene effects on height were so small that individually we were unable to detect them. However, when we studied the impact of all the common variants together we realised their cumulative effect was in fact very significant.”
These results are consistent with work completed by Visscher and colleagues last year who discovered that many common genetic variants together contribute to a person’s risk of developing schizophrenia and these variants can explain at least a third of the risk of inheriting the disease.
The research was carried out in collaboration with the University of Melbourne and Washington University (USA) and will be reported online in Nature Genetics on Monday 21 June 2010 and can be downloaded at http://dx.doi.org/10.1038/ng.608