10,000 genetic markers key to a person’s height

NEW DELHI: Approximately 10,000 genetic markers may together hold the key to why some people are tall and others aren’t, according to the study of genomic data of over 4 million people by a team of researchers in Australia.

The study says it has found markers that could explain close to 80% of variations in height, the most that can be attributed yet. This is in line with studies among identical twins that previously have projected that up to 80% of variation behind a person’s height could just be genes.

“This is a genuine landmark,” Daniel MacArthur of the Garvan Institute of Medical Research in Australia told Science Mag, which first reported about the study. The report adds that the findings could open the door to new understanding that could eventually lead to personalised medicines.

The analysis is based on a genomic study of 4.1 million individuals of European ancestries. Selecting a particular geographic ancestry enables the researchers to rule out the influence of nutrition and other environmental factors (such as exposure to different diseases) that may also play a role.

Such study, termed a genomewide association study (GWAS), involves the mapping of genetic markers with different traits and diseases, and ultimately helps scientists zero in on sets of genes or genetic markers that could explain why some people have certain attributes or may be susceptible to certain diseases.

The study by the Australian researchers, led by Loïc Yengo and Peter Visscher, is based on research spread over multiple years, the report adds. Over these years, this work has identified 9,900 genetic markers which may be a common factor.

What this essentially means is that someone with sets of these genetic markers common with another person is equally likely to be as tall or as short as them. The report, however, adds that “few of the height-linked DNA markers have been tied to specific genes that clearly alter the trait”. “It’s mostly all still ‘missing’ in a biological sense,” the Science report quoted David Goldstein of Columbia University as saying.

But, largely, the findings raise the chances of researchers being able to whittle down these common genetic markers soon. Instead of being scattered ran

domly across the entire genome, which would make it challenging to ever get a handle on the specific genes and their roles, the 9,900 or so markers are confined to only about 30% of the genome, the report quoted Yengo as saying.

“And many cluster in areas known to contain genes involved in growth,” the study added.