The biological definition of race is: a population, or group of populations, within a species that has measurable, defining biological characteristics and an Fst of at least 0.25 relative to other populations of the species.
Fst scores among humans average 0.17. So there are no biological races within H. sapiens. Also there is no way to look at a gene and determine "race". In other words, there are no genes or alleles that are Black, White, Asian or any of the other major "races" that society has made up.
Arathi- the question was about the biological definition, not "what is your opinion" or "what is the taxonomy of H. sapiens".
Taxonomy and race are not the same. Race and subspecies, however, are. If you honestly believe that skin colors separate human beings into groups based on shades of brown, there isn't much I can do to explain it to you. There are many genes that code for skin color. Sure, you can tell if someone had a high level of melanin production. But can you distinguish an East African from an Austrailian aborigine? No. One could tell that both had dark skin, and that is all. Again, there is not enough variation in the human population to separate them into races, or subspecies. My answer is based on scientific facts, not opinion. mmmkay?
Forgot my source the first time: Core Concepts in Biological Anthropology, Augustin Fuentes. McGraw Hill. 2008.