Original: Current research has established that human beings are genetically highly homogenous; that is, the DNA of individuals is more alike than usual for most species, which may have resulted from their relatively recent evolution or the Toba catastrophe.
Simplified: Current research has established that human beings are genetically highly homogenous. The DNA of individuals is more alike than usual for most species. This may have resulted from their relatively recent evolution or the Toba catastrophe.