A graph detailing the origin of modern humans using the Polygenism theory of human evolution.

The multiregional hypothesis for the human species holds that the evolution of humanity throughout the Pleistocene has been within a single widespread human species, Homo sapiens, in response to the normal forces of evolution: selection, mutation, genetic drift, and gene flow. Image File history File links Multiregionaltheory. ... Image File history File links Multiregionaltheory. ... Human evolution is the part of the theory of evolution by which human beings emerged as a distinct species. ... A hypothetical phylogenetic tree of all extant organisms, based on 16S rRNA gene sequence data, showing the evolutionary history of the three domains of life, bacteria, archaea and eukaryotes. ... The Pleistocene epoch (pronounced like ply-stow-seen) is part of the geologic timescale. ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ... A hypothetical phylogenetic tree of all extant organisms, based on 16S rRNA gene sequence data, showing the evolutionary history of the three domains of life, bacteria, archaea and eukaryotes. ... In biology, mutations are changes to the genetic material (usually DNA or RNA). ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ...

Overview

The multiregional hypothesis was first formulated in the early 1980's by Milford H. Wolpoff and a group of associates as an explanation for apparent similarities of the remains from Homo erectus and Homo sapiens inhabiting the same region. This phenomenon was termed Regional continuity and to begin with, baffled the scientists. This regional continuity could only be explained if Homo erectus and Homo sapiens were the same species and there had been just enough interbreeding to cause an overall global development towards the latter, but without stamping out the regional adaptation that had been developed by the former. Such a delicate balance seemed unlikely and this was what had the anthropologists puzzled. Milford H. Wolpoff (born in 1942 in Chicago, Illinois) is a physical anthropologist. ... Binomial name †Homo erectus (Dubois, 1892) Subspecies Homo erectus (upright man) is a hominin species that is believed to be an ancestor of modern humans (with Homo heidelbergensis usually treated as an intermediary step). ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ... See Anthropology. ...

Eventually, Milford H. Wolpoff proposed an explanation based on clinal variation that would allow for the necessary balance. Thus was born the Multiregional hypothesis: That those people we call Homo erectus, Neandertals and others along with Homo sapiens, formed a single species. This species - posits the Multiregional hypothesis - arose in Africa two million years ago in the form we call Homo erectus and then spread out over the world, developing adaptations to regional conditions. In population genetics, a cline is a gradual change of a character or feature (phenotype) in a species over a geographical area, often as a result of environmental heterogeneity. ... Binomial name Homo neanderthalensis King, 1864 The Neanderthal or Neandertal was a species of genus Homo (Homo neanderthalensis) that inhabited Europe and parts of western Asia from about 230,000 to 29,000 years ago (in the Middle Palaeolithic, early Stone Age). ...

For periods of time some populations could become isolated, developing in a rather different direction (this would be the case with the Neandertals). But through a complicated process involving above all continuous interbreeding, but also examples of replacement, genetic drift and other vehicles of evolution, adaptations that were an advantage anywhere on earth would spread: Thus the development of the species would proceed in overall the same direction, while maintaining regional adaptation to climate, diet etc. Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ... A hypothetical phylogenetic tree of all extant organisms, based on 16S rRNA gene sequence data, showing the evolutionary history of the three domains of life, bacteria, archaea and eukaryotes. ...

Eventually, the more unusual local varieties of the species would have disappeared in favor of modern humans, with some of the same regional adaptations acquired since first spreading over Earth, but as well with many common features.

Multiregional hypothesis and other theories of human origin

Multiregional evolution contrasts with two theories. According to the "Eve theory," human evolution was a consequence of many cases of species replacement, as newer species replaced older ones across the human range. Modern human origins, according to the "Eve theory," is the most recent example of species replacement. The other theory is Polygenic evolution, a multiple origins theory in which the different human populations or races had independent origins and evolved in isolation from each other. Held by many scholars of the 19th century such as Haeckel and Klaatsch, and even some of the 20th, such as Carleton Coon, it is biologically impossible since all populations of a species must have the same, single origin. In paleoanthropology, the single-origin hypothesis (or Out-of-Africa model, or Replacement Hypothesis) is one of two accounts of the origin of anatomically modern humans, Homo sapiens. ... Human origins may refer to: Origin beliefs, supernatural explanations of the origin of the world and humankind Human evolution, current scientific theories of the development of the human species This is a disambiguation page: a list of articles associated with the same title. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Carleton Stevens Coon, (23 June 1904 — 6 June 1981) was an eminent American anthropologist. ...

Polygenism is sometimes mistaken for Multiregional evolution, because they are both hypotheses of evolution within a single species. However, Polygenic evolution depends on isolation of populations while Multiregional evolution requires population interactions and interbreeding so that genetic changes can spread throughout the human range, especially when they are promoted by natural selection. According to the Multiregional hypothesis, geographic differences between human populations are the results of climatic variation, isolation by distance, and historical accidents (genetic drift). Polygenism is a biblical theory of human origins positing that the human races are of different lineages. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years Climate change refers to the variation in the Earths global climate or regional climates over time. ... Geographic isolation, or allopatry, is a term used in the study of evolution. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ...

Recent evidence

The multiregional hypothesis was originally developed from the fossil evidence, but more recent work has focused on molecular data, in which DNA is sequenced. Because this hypothesis posits that human evolution has been within a single species, and not between species as one species replaced another (Eve Theory), it makes genetic predictions. These predictions have been met with the continued study of non-recombining DNA such as mitochondrial DNA and the Y chromosome, as well as regions of Nuclear DNA where recombination is usual. These genetic studies show an ancient history of population mixture throughout the world, perhaps as far back as 2 or more million years. Since for most of that time the majority of humans lived in Africa^{[citation needed]}, more genes moved out of Africa than into it, but gene movements were always multidirectional. The genetic studies also show the independent evolution of different genes; their evolution does not reflect a recent species replacement, which would have affected all genes the same way because of the associated period of very small population size causing a genetic bottleneck. It has been suggested that Fossil record be merged into this article or section. ... Molecular biology is the study of biology at a molecular level. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid — usually in the form of a double helix — that contains the genetic instructions or genocode monitoring the biological development of all cellular forms of life, and many viruses. ... In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. ... Recombination usually denotes a genetic event that occurs during the formation of sperm and egg cells (especially in areas of study of biology topics). ... Mitochondrial DNA (mtDNA) is DNA that is located in mitochondria. ... The human Y chromosome is one of two sex chromosomes, it contains the genes that cause testis development, thus determining maleness. ... Nuclear DNA is DNA contained within a nucleus of eukaryotic organisms. ... For other uses, see Africa (disambiguation). ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... In population genetics and population ecology, population size (usually denoted N) is the number of individual organisms in a population. ...

Studies on past population bottlenecks that can be inferred from molecular data have led Multiregionalists to conclude that the recent single-origin hypothesis is untenable because there are no population size bottlenecks affecting all genes that are more recent than the one at the beginning of the species, some 2 million years ago. Discovery of a possible hybrid Homo sapiens X neanderthalensis fossil child at the Abrigo do Lagar Velho rock-shelter site in Portugal in 1999 further supports the Multiregional hypothesis, by reflecting the inter-mixture of diverse human populations. A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ... In paleoanthropology, the single-origin hypothesis (or Out-of-Africa model, or Replacement Hypothesis) is one of two accounts of the origin of anatomically modern humans, Homo sapiens. ... A bottleneck is literally the neck of a glass or pottery bottle. ... The site and the Upper Paleolithic human burial The Lagar Velho site is a rock-shelter in the Lapedo valley, a limestone canyon ca. ...

A recent Australian study of an ancient Aboriginal skeleton known as Mungo Man supports the multiregional hypothesis. Genetic tests show the mitochondrial DNA of Mungo Man to be from a mtDNA lineage with no descendants today. Yet Mungo man is an anatomically modern human and has been dated to be at least 40,000 years old. The study suggests that mtDNA does not reflect ancestry or divergence times, and this interpretation is supported by the discovery that the gene is subject to natural selection. The Mungo Man (also known as Lake Mungo 3) was an early human inhabitant of the continent of Australia, who is believed to have lived about 40,000 years ago, during the Pleistocene epoch. ... Hypothesized map of human migration based on mitochondrial DNA. In human genetics, Human mitochondrial DNA haplogroups are haplogroups defined by differences in human mitochondrial DNA. These haplogroups trace the matrilineal inheritance of modern humans back to human origins in Africa and the subsequent spread across the globe. ... For other uses, see Human (disambiguation). ... In vector calculus, the divergence is an operator that measures a vector fields tendency to originate from or converge upon a given point. ... Natural selection is the process by which individual organisms with favorable traits are more likely to survive and reproduce. ...

A recent, non-fossilized discovery of one metre-tall, small-brained (350 cc), Homo floresiensis, on the Indonesian island of Flores, might imply populations of Homo erectus survived very late, and gave rise to even later, physically dwarfed isolated "erectus" groups. However, this possibility does not address the Multiregional hypothesis, which is only about the human species, and the evidence is marred by the possibility that the single dwarf cranium found on Flores might have been pathological. A cubic centimetre (cm3) is an SI derived unit of volume, equal to the volume of a cube with side length of 1 centimetre. ... Binomial name †Homo floresiensis P. Brown et al. ... Map of Flores Island Flores (Portuguese for flowers) is one of the Lesser Sunda Islands, an island arc with an estimated area of 14,300 km² extending east from the Java island of Indonesia. ... Binomial name †Homo erectus (Dubois, 1892) Subspecies Homo erectus (upright man) is a hominin species that is believed to be an ancestor of modern humans (with Homo heidelbergensis usually treated as an intermediary step). ...

Proponents of Multiregionalism

Besides Milford H. Wolpoff, paleoanthropologists most closely associated with the multiregional hypothesis include James Ahern, James Calcagno[1], Rachel Caspari, David Frayer, Mica Glanz, John Hawks[2], Andrew Kramer, Sang-Hee Lee, Alan Mann, Janet Monge, Jakov Radovcic, Karen Rosenberg, Mary Russell, Lynne Schepartz, Fred Smith, Alan Thorne, Adam Van Arsdale, Bernard Vandermeersch. Milford H. Wolpoff (born in 1942 in Chicago, Illinois) is a physical anthropologist. ... Paleoanthropology is the branch of physical anthropology that focuses on the study of human evolution, tracing the anatomic and genetic linkages of pre-humans from millions of years ago, up to modern times. ...

See also

• Genetics
• Human evolution
• Mitochondrial Eve
• Y-chromosomal Adam

Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ... Human evolution is the part of the theory of evolution by which human beings emerged as a distinct species. ... Mitochondrial Eve is the name given by researchers to the woman who is the most recent common matrilineal ancestor of all living humans. ... In human genetics, Y-chromosomal Adam (Y-mrca) is the male counterpart to mitochondrial Eve: the most recent common ancestor from whom all male human Y chromosomes are descended. ...

External links

• [3] - 'Genomics refutes an exclusively African origin of humans' (pdf) Vinayak Eswaran, Henry Harpending, Alan R. Rogers, Journal of Human Evolution (2005)
• [4] - 'Templeton tree'
• [5] - 'The Hybrid Child from Portugal'
• ActionBioscience.org - 'Origins of Modern Humans: Multiregional or Out of Africa?' (discoverer of 'Lucy' argues against multi-regionalism), Donald Johanson, American Institute of Biological Sciences (May, 2001)
• Biochem. Soc. Trans (2005) 33, 582-585 - J. Hardy and others - Molecular Mechanisms of Neurodegeneration (Evidence suggesting that Homo neanderthalensis contributed the H2 MAPT haplotype to Homo sapiens)
• Gene Expression - 'Population genetics notes' (only 1 migrant per generation between populations of any size can prevent divergence in allelic frequencies)
• Genetics - 'Deep Haplotype Divergence and Long-Range Linkage Disequilibrium at Xp21.1 Provide Evidence That Humans Descend From a Structured Ancestral Population' (first genetic evidence that statistically rejects the null hypothesis that our species descends from a single, historically panmictic population), Daniel Garrigan, Zahra Mobasher, Sarah B. Kingan, Jason A. Wilder, and Michael F. Hammer, University of Arizona, Tucson, Genetics, Vol. 170, 1849-1856, August 2005
• Linfield.edu - 'The Origin of Modern Humans: Multiregional and Replacement Theories', Michael Roberts, Linfield College
• OxfordJournals.org - 'Evidence for Archaic Asian Ancestry on the Human X Chromosome' (suggests ancient RRM2P4 lineage is remnant of introgressive hybrid of anatomically modern humans from Africa and archaic populations in Eurasia), Daniel Garrigan, Zahra Mobasher, Tesa Severson, Jason A. Wilder, Michael F. Hammer, University of Arizona, Tucson, Molecular Biology and Evolution, vol 22, no 2, p 189-192 (2005)
• PLoS Genetics - 'Possible ancestral structure in human populations', Vincent Plagnol, Jeff D. Wall, PLoS Genetics, (2006) (evidence for ancient admixture in both a European and a West African population (p ~ 10^-7), with contributions to the modern gene pool of at least 5%. While Neanderthals form an obvious archaic source population candidate in Europe, there is not yet a clear source population candidate in West Africa.)
• PNAS.org - 'Mitochondrial DNA sequences in ancient Australians: Implications for modern human origins', Gregory J. Adcock, Elizabeth S. Dennis, Simon Easteal, Gavin A. Huttley, Lars S. Jermiin, W. James Peacock, Alan Thorne, Australian National University, Proceedings of the National Academy of Sciences, vol 98, no 2, p 537-542 (January 16, 2001)
• StephenJayGould.org - 'Out of Africa vs. Multiregionalism', Tod Billings (December 7, 1999)
• TalkOrigins.org - 'The evolution of modern humans: where are we now?' Christopher B. Stringer, General Anthropology, vol 7, no 2, p 1-5 (2001)