Genetics: Study of Height

Genetics

After a recent study, a group of scientists have come to understand the genetic components which contribute to height. Their results have confirmed findings unearthed in prior studies. Thus, questions about varying heights between mothers, fathers, sisters, and brothers can be answered with greater confidence.

Scientists have worked to determine the genetics behind height variations. In what researchers are calling the biggest study of its kind to date, they have analyzed genome data in over 250 thousand people. Their analysis found almost 700 genetic variants and over 400 genome regions relative to height.

According to the study, 80 percent of height can be attributed by genetics. Environmental factors and nutrition account for the remaining 20 percent. Nutrition, in part, can account for the height increasing with the most recent generations of people throughout the world.

Geneticist Dr. Joel Hirchhorn says the purpose of the study is to obtain a model for human disease. Also a pediatric endocrinologist, Dr. Hirchhorn ascertains that studying diseases such as diabetes, obesity, and asthma are made possible through genetic models used to study height. Hirchhorn practices at Boston Children’s Hospital, the Broad Institute of MIT (Massachusetts Institute of Technology), and Harvard.

Pediatric endocrinologists have experienced a significant clinical issue in short stature during childhood. Identifying the interaction of genes with other variants central to one’s height could assist doctors in diagnosing children whose short stature could be the result of one central underlying source.

The data was analyzed by an international team of researchers. Researchers examined genomes belonging to 253,288 people with European origins. The subjects come from Europe, Australia, and North America. Approximately two million shared genetic variants were observed in the subjects. Relative to height, 697 gene variants were identified in 424 gene regions.

The journal, Nature Genetics, has published the study on height. Researchers suspect a lot of the genes identified in the study were pivotal to skeletal growth, but that their involvement was not previously accounted for. Collagen, a bone component, and chondroitin sulfate, a cartilage component, were also related. Growth plates – an area located near the ends of long bones where tissue grows – were related as well.

Timothy Frayling, a geneticist from Britain’s University of Exeter, says they discovered that DNA contained variants that accounted for 20 percent of genetics relative to height. He recalls a previous situation when they had not known the relationship between genes and human genome regions as it related to height variations.

The previous study sampled twins and results showed that nearly genetic variation accounted for 90 percent of normal variation in the height of humans. The variants were likely distributed among countless genes. Frayling and Hirschhorn teamed up with Mark McCarthy and others in the study of genome association in 5,000 people. Two variants conterminous to HMGA2 were found to be connected to height variation.

In the previous study, the team of researchers used a smaller sample of people in which they discovered 199 genetic variants inhabiting 180 genome regions. Hirchhorn says multiplying the sample size by two doubles the gene regions associated with height. In turn, the numbers of genes by which to connect the biology of average skeletal growth can be increased seven-fold.

The scientists have come a long way in three years’ time. Information derived from the study gets medication and science professionals closer to understanding some human illnesses and theories about physical attributes. The next study is likely to render more definitive conclusions regarding genetics and height.

By Charice Long

Sources:
Reuters
Time
Nature Genetics

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