Racism
However, scientists say that humans do not really fit well into these categories, biologically.  The DNA of people from different races is very similar.  Evidence from genetics and archaeology suggests that all humans came from the same group of early humans in East Africa.  This means that different races did not appear at different times.  All humans came from the same race, and separated into different races later. Because white people historically had more power, some people call racism against whites reverse racism.