The distribution of genetic variants within and among human populations are impossible to describe succinctly because of the difficulty of defining a population, the clinal nature of variation, and heterogeneity across the genome (Long and Kittles 2003). In general, however, an average of 85% of statistical genetic variation exists within local populations, ~7% is between local populations within the same continent, and ~8% of variation occurs between large groups living on different continents. The recent African origin theory for humans would predict that in Africa there exists a great deal more diversity than elsewhere and that diversity should decrease the further from Africa a population is sampled. Hence, the 85% average figure is misleading: Long and Kittles find that rather than 85% of human genetic diversity existing in all human populations, about 100% of human diversity exists in a single African population, whereas only about 60% of human genetic diversity exists in the least diverse population they analyzed (the Surui, a population derived from New Guinea). Statistical analysis that takes this difference into account confirms previous findings that, "Western-based racial classifications have no taxonomic significance."