Structure and Dynamics

From Darwin’s time in biology and even before Darwin in linguistics, the tree diagram has been the primary formal depiction of descent. The underlying logic of the dendrogram depends on a branching process: units fission, then diversify through time. This model of differentiation is generally correct for the evolution of species, languages, and genes. However, at the level of human populations, subject to the ramifying effects of gene flow and natural selection, a better model is a reticulating network. This paper will critically examine genetic dendrograms based on “classical” loci as well as mitochondrial DNA in the context of the history of Malaysian Orang Asli populations.