The world’s largest study into the genetics behind human height has discovered the trait’s vast complexity.
Researchers at The University of Queensland took a leading role in the analysis of more than a quarter of a million samples, finding hundreds of new genes that play a role in determining height.
Co-senior investigator Professor Peter Visscher, from UQ’s Queensland Brain Institute (QBI), said the discovery would help provide a model for genetic studies of other human traits and of diseases such as psychiatric disorders and dementia.
“Just as neuroscientists use experimental organisms as a model to study brain function, geneticists use human height as a model trait to study genetic variation,” he said.
The study involved more than 300 organisations across the world and found 697 DNA variants which influence height.
Joint-lead author and QBI researcher Dr Jian Yang said the findings were significant because they proved exactly how complicated human height is.
“The DNA variant with the largest effect on height only has an impact of about five millimetres, and most of the other variants have a much smaller effect,” Dr Yang said.
“Taken together, all DNA variants we discovered account for height differences spanning approximately 11 centimetres.”
“This shows that the genetic basis for height isn’t controlled by a single gene or small group of genes – there are thousands of genes involved.
“It’s estimated that about 80 per cent of a normal healthy individual’s height is controlled by heritable genetic factors, and we’ve only discovered around one-fifth of those genes.
“The remaining 20 per cent is determined by environmental factors such as nutrition and healthcare in childhood.”
The research harnessed a genome-wide association study (GWAS) which sifted through two million DNA variants in more 250,000 individuals to identify the genetic variants influencing height.
“Sample size is critical in a GWAS study because the more people you include, the greater statistical power you have to distinguish the subtle height difference between groups of people carrying different genetic variants,” Dr Yang said.
The study, jointly led by the University of Exeter, Harvard University, and UQ, is published in Nature Genetics.