Health Business Blog � Blog Archive � Are we really 99.9 percent identical? No.

Health Business Blog � Blog Archive � Are we really 99.9 percent identical? No.: "The 99.9% number that you hear about is bogus. The human genome has about 2 or 3 billion DNA base pairs. That is indeed about 99.9% similarity at the level of DNA base pairs, but if all of our DNA consisted of our ~20,000 genes and associated regulatory areas, the differences observed would average about 200 differences per gene. In practice, many genetic differences are outside coding areas, and many differences in proteins are relatively or completely silent when translated into proteins, but still the notion of sharing 99.9% of our genes is totally bogus. Sharing 99.9% of DNA base pairs is very different from sharing 99.9% of genes. It would be interesting if the paper actually runs the numbers of the number of genes that are identical at the amino acid level (this controls for redundancies in the genetic code). This probably comes as no surprise to most folks, who know that kids tend to look like their biological parents. But it will be a surprise to many people."

Putting some perspective on recent genetics news.