What we're trying to do in behavioral genetics and medical genetics is explain differences. It's important to know that we all share approximately 99 percent of our DNA sequence. If we sequence, as we can now readily do, all of our 3 billion base pairs of DNA, we will be the same at over 99 percent of all those bases. That's what makes us similar to each other. It makes us similar to chimps and most mammals. We're over 90 percent similar to all mammals. There's a lot of genetic similarity that's important from an evolutionary perspective, but it can't explain why we're different. That's what we're up to, trying to explain why some children are reading disabled, or some people become schizophrenic, or why some people suffer from alcoholism, et cetera. We're always talking about differences. The only genetics that makes a difference is that 1 percent of the 3 billion base pairs. But that is over 10 million base pairs of DNA. We're looking at these differences and asking to what extent they cause the differences that we observe. 

ROBERT PLOMIN is a professor of behavioral genetics at King's College London and deputy director of the Social, Genetic and Developmental Psychiatry Centre at the Institute of Psychiatry, Psychology and Neuroscience. Robert Plomin's Edge Bio Page [2]