Genetic variation is a term that is used to describe the DNA sequence variation in human genomes. It is what makes all people unique, whether in terms of skin color, the shape of our faces, or hair color. Although individuals of same species have similar characteristics, they are rarely identical. That difference in those individuals is referred to as variation.
Amongst people, single nucleotide polymorphisms are the most common type of genetic variation. Each nucleotide polymorphism denotes a difference in a base of single DNA. In a person’s DNA, DNA bases are A, C, G or T.
Genetic variation is a result of different alleles of genes. For instance, looking at eye color, individuals with blue eyes have a unique allele of the gene for eye color, while individuals with brown eyes have a different allele of the gene.
Face shape, height, skin tone and eye color are all determined by our genes. Therefore, any variation that occurs is due to the genes we inherit from our parents. In contrast, while weight is partly influenced by genes, it is highly influenced by environment. For example, how often we exercise and how much we eat.