What makes tall people tall and short people short is becoming less of a mystery to scientists. An international team of researchers has identified nearly 700 gene variants in more than 400 gene regions that are connected to height — an estimated 20 percent of all the gene variants that play a role in determining one’s size.

The findings of the study were published in the journal Nature Genetics, Reuters reports. It is believed to be the biggest study of its kind to date.

Scientists believe that about 80 percent of a person’s height is hereditarily determined, with environmental factors such as nutrition determining the rest. The average height of humans around the world has risen throughout the last few generations as world nutrition generally improves.

Researchers studied the genomes of 253,288 people from Europe, North America and Australia, all with European ancestry and found 424 gene regions with 697 gene variants that are linked to height. Many of the genes identified were not previously known to have an effect on skeletal growth.

“For over 100 years, [height has] been a great model for studying the genetics of diseases like obesity, diabetes, asthma that are also caused by the combined influence of many genes acting together,” Dr. Joel Hirschhorn, a pediatric endocrinologist and geneticist at Boston Children’s Hospital and the Broad Institute. “So by understanding how the genetics of height works, we can understand how the genetics of human disease works.”

[Reuters]

Write to Nolan Feeney at nolan.feeney@time.com.