Why are humans different heights? Scientists answer the long and short of height questions as they pin down genetic mutations

Research could lead to a breakthrough in forensic science that allows scientists to estimate a person’s height from DNA samples left at the scene of a crime

Scientists have come closer to answering the question of why some children are destined to grow tall while others will end up shorter than average following a study that has identified hundreds of genetic mutations influencing human height.

Although genes have been known to be central to height for many years, researchers now believe they have found some of the key genetic elements that contribute to at least 20 per cent of the variation seen within the human population.

The findings could help doctors to diagnose growth abnormalities in children, as well as helping to understand height-related illnesses such as osteoporosis, cancer and heart disease, the researchers said.

The research could also lead to a breakthrough in forensic science that allows scientists to estimate a person’s height from DNA samples left at the scene of a crime, said Professor Tim Frayling of the University of Exeter, one of the lead authors of the study published in Nature Genetics.

“In a few years times it may well be possible to take a DNA sample from a crime scene and tell a policeman that the suspect is likely to be a certain height, or at least to narrow the height down,” Professor Frayling said.

The research involved scanning the entire genomes of more than 250,000 people to search for single point mutations in the DNA that play a role in influencing a person’s height. It found nearly 700 genetic variants located within just over 400 regions that collectively contributed to a fifth of the genetic variation in height.

“Despite knowing that height was genetic, before this research we knew absolutely nothing about the genes involved. Yet how a baby grows into a fully-growth adult is a fascinating transformation that we’d like to know more about,” Professor Frayling said.

About 80 per cent of the normal variation in human height is the result of inherited genetic differences between people, with the rest of the height difference being due to environmental influences, such as diet or upbringing.

“It’s common knowledge that people born to tall parents are more likely to be tall themselves. Most of this is down to the variations in our DNA sequence that we inherit from our parents – the different versions of all our genes,” Professor Frayling said.

“We have now identified nearly 700 genetic variants that are involved in determining height. This goes a long way towards fulfilling a scientific curiosity that could have real impact in the treatment of diseases that can be influenced by height, such as osteoporosis, cancer or heart disease,” he said.

“It is also a step towards a test that may reassure parents worried that their child is not growing as well as they’d hoped – most of these children have probably simply inherited a big batch of ‘short genes’,” he added.

Widening the scope of the study to include millions of people from different ethnic backgrounds could eventually lead to the identification of all the key genes involved in determining the inherited component of height, and will lead to a better understanding of the factors influencing abnormal growth, said Joel Hirschhorn of Boston Children’s Hospital.

“Many of the genes we identified are likely to be important regulators of skeletal growth, but were not known to be involved until now. Some may also be responsible for unexplained syndromes of abnormal skeletal growth in children,” Professor Hirschhorn said.

“As you increase the sample size, you get more biology,” he said.

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