Researchers have found that a single change in genetic sequence of the fat mass and obesity-associated FTO gene has a significant effect on the variability of body mass index (BMI).

This change, referred to as a single nucleotide polymorphism (SNP), is the replacement of one nucleotide with another. Nucleotides are the units that make up our DNA.

This is the first study to identify specific genes or mechanisms that explain the phenomenon of genetic differences in variability of specific traits witnessed in many plant and animal species.