Multiregional thesis or theory (MRT) represents one side of the most hotly contended debate in the academic field of paleoanthropology, a discipline concerned with the origins, development and migrations of the human species and its primate ancestors. MRT takes issue with the previously dominant suppositions of its competitor thesis, Out of Africa theory (OOA). Both the MRT and OOA camps have their own evidence and continue to be contentious opponents in contemporary study.
Each school believes that Homo erectus emerged from Africa. OOA theory postulates that this diaspora led to isolated communities that, in some cases, developed distinct species such as Neanderthals. Homo sapiens, however, emerged much later in Africa alone. MRT claims that while somewhat isolated, the Homo erectus communities also had some genetic exchange with one another and that a process of natural selection within them allowed Homo sapiens to evolve wherever these protohumans were living.
To explore and back their claims, both MRT and OOA camps rely on anatomical, archaeological and genetic evidence. Taken together, scientists try to piece together a more accurate picture of the physical, cultural and material development of early hominids in excavation sites. Anatomical evidence often involves the structure of craniums and jaw bones as well as the overall robustness of the skeletal frame. Archaeologists attend to the nature and sophistication of tools, ritual items and the construction of shelters. Finally, genetics researchers employ materials like mitochondrial DNA to perceive even the smallest differences in genetic makeup between specimens.
As of the early 21st century, much of the evidence tends to support the OOA position. The tiny differences located in early human genetic codes suggest that humans evolved from a limited gene pool -- such as in Africa. Furthermore, genetic evidence indicates that the evolution of Homo sapiens occurred later than is speculated by MRT. In the end, however, the veracity and clarity of evidence are not entirely conclusive. The debates raging between these two theories will likely extend further.