Models Of Human Origins Research Articles

A new model of human origins in Africa

A new model of human origins in Africa

Natural relativism in lieu of moral absolutism

Natural relativism in lieu of moral absolutism

Deep Skull From Niah Cave and The Pleistocene Peopling of Southeast Asia

The Deep Skull from Niah Cave in Sarawak (Malaysia) is the oldest anatomically modern human recovered from Southeast Asia.For more than 50 years opinions about its relevance to tracing the prehistory of recent people in the region have been in a state of flux. The most widely held view traceable to Brothwell’s initial description and analysis is that the individual is related to Indigenous Australians and provides evidence to support the ‘two-layer’ model of human origins in Southeast Asia. Here we undertake a new assessment of the potential of the Deep Skull to inform these issues and in doing so provide a description of the specimen including a reassessment of its ontogenetic age, sex, morphology and affinities. We find that this individual was most likely to have been of advanced age and a female rather than an adolescent male as originally suggested. We also find that its morphology points towards its affinities being beyond Indigenous Australasians to East Asians. We propose that the Niah individual might best be considered part of a Negrito population that inhabited Borneo during the Pleistocene perhaps establishing their presence in Northern oceanic Southeast Asia by ~36 kyr.

RETRACTED: Do pigmentation and the melanocortin system modulate aggression and sexuality in humans as they do in other animals?

Pigmentation of the hair, skin, cuticle, feather and eye is one of the most salient and variable attributes of vertebrates. In many species, melanin-based coloration is found to be pleiotropically linked to behavior. We review animal studies that have found darker pigmented individuals average higher amounts of aggression and sexual activity than lighter pigmented individuals. We hypothesize that similar relation- ships between pigmentation, aggression, and sexuality occur in humans. We first review the literature on non-human animals and then review some of the correlates of melanin in people, including aggression and sexual activity. Both within human populations (e.g., siblings), and between populations (e.g., races, nations, states), studies find that darker pigmented people average higher levels of aggression and sexual activity (and also lower IQ). We conceptualize skin color as a multigenerational adaptation to differences in climate over the last 70,000 years as a result of ''cold winters theory'' and the ''Out-of-Africa'' model of human origins. We propose life history theory to explain the covariation found between human (and non-human) pigmentation and variables such as birth rate, infant mortality, longevity, rate of HIV/AIDS, and violent crime.

Modern human origins: continuity, replacement, and masticatory robusticity in Australasia

Morphological evidence for a Multiregional (MR) model of human origins is suggested by a series of “linking traits” seen in the crania of late Javanese Homo erectus from Ngandong and anatomically modern Australian crania. A few studies that consider the genetic, structural, or functional aspects of these regional traits suggest their appearance is heavily influenced not by shared phylogeny but by a common “strong” masticatory pattern. Using dental occlusal areas, external mandibular metrics, internal biomechanical properties of the mandibular corpus measured from CT scans, and nonmetric traits associated with the attachment of masticatory muscles, we test the hypothesis that Australians exhibit evidence of a “strong” masticatory pattern. We use a mixed-sex comparative human sample ( n = 415) that includes precontact Alaskans from Point Hope and the Aleutian Islands, Californians, Peruvians, an urban forensic sample, and the late Pleistocene Afalou–Taforalt sample. In comparison with recent humans known to exhibit such patterns, Australian mandibles show none of the expected changes related to producing and dissipating heavy occlusal loads. This is true regardless of whether external or internal mandibular dimensions are considered, albeit Australians show large occlusal areas and relatively large section modulus indices. Thus, a prime functional argument proposed for the origin of some Australian regional features is not supported by these data.

Deep Divergences of Human Gene Trees and Models of Human Origins

Two competing hypotheses are at the forefront of the debate on modern human origins. In the first scenario, known as the recent Out-of-Africa hypothesis, modern humans arose in Africa about 100,000-200,000 years ago and spread throughout the world by replacing the local archaic human populations. By contrast, the second hypothesis posits substantial gene flow between archaic and emerging modern humans. In the last two decades, the young time estimates--between 100,000 and 200,000 years--of the most recent common ancestors for the mitochondrion and the Y chromosome provided evidence in favor of a recent African origin of modern humans. However, the presence of very old lineages for autosomal and X-linked genes has often been claimed to be incompatible with a simple, single origin of modern humans. Through the analysis of a public DNA sequence database, we find, similar to previous estimates, that the common ancestors of autosomal and X-linked genes are indeed very old, living, on average, respectively, 1,500,000 and 1,000,000 years ago. However, contrary to previous conclusions, we find that these deep gene genealogies are consistent with the Out-of-Africa scenario provided that the ancestral effective population size was approximately 14,000 individuals. We show that an ancient bottleneck in the Middle Pleistocene, possibly arising from an ancestral structured population, can reconcile the contradictory findings from the mitochondrion on the one hand, with the autosomes and the X chromosome on the other hand.

The Origin of Man Behind the Veil of Ignorance: A Psychobiological Approach

The pair-bond model of human origin proposed by Lovejoy in his “Reexamining Human Origins in Light of Ardipithecus ramidus” (2009) combines fossil records with the unique sexual behavior of modern humans. This construct, however, seems to lack an emotionally important element. By connecting ovulatory crypsis with frontal copulation and face-to-face contact, the transition to the complexity and subtlety of human emotional life becomes more evident. Reproductive success and emotional representation are considered as two interacting levels in the phylogenetic scale. Thus, the behavioral frame of sociobiology is extended to psychobiological phenomena and a bridge is built between natural sciences and philosophy. Light from both sides will be thrown on the origin of man, including his unique cultural history.

Whites "Blacken'd" and Men "Guilty of Whoredom": Sex and Race in the Colonies

In 1745, a doctor named Josiah Hart went to the North Carolina lower court to sue a local planter for slander. The planter had told neighbors that Hart was Guilty of whoredom because he had knockt a Negro Whench who belonged to the planter-an accusation that, Hart insisted, had hurt, Blacken'd & made loose honor and character. Hart initiated the slander suit, therefore, to rescue his Bussiness and Practice and chances for a respectable marriage (p. 150). This case-one of the most vivid in Kirsten Fischer's fine book, Suspect Relations: Sex, Race, and Resistance in Colonial North Carolina-prompts numerous questions about the intersection of race and sexuality in early America. Fischer sees large changes at work in eighteenthcentury court cases like this one that foregrounded conflicts and assumptions about both race and sex. She argues that the gradual emergence of a racial hierarchy during that period resulted from the interplay between conceptions of race and sex-and that ordinary men and women contributed to the construction and hardening of those social categories. Particularly in court cases that involved interracial sexual relationships, Fischer finds ordinary people expressing new ideas about race. As she put it, When sexual coercion was linked to a racial hierarchy, each made the other seem more 'natural,' that is, the result of innate, biological facts (p. 6). Fischer's work contributes to a body of scholarship that has traced profound changes in racial ideologies over the course of the eighteenth century. During that period new colonial laws and European scientific theories combined to support the notion that race was a biological essence that undergirded the social hierarchy of white over black. Eighteenth-century thinkers (scientists, philosophers, and theologians) theorized that humans had developed from multiple origins, rather than a single, Adam-and-Eve model of human origin. This altered longstanding notions of race as mutable, dependent upon climate and geography, and paved the way for a conception

Ethnic divergence and linkage disequilibrium of novel SNPs in the human NLI-IF gene: evidence of human origin and lack of association with tuberculosis susceptibility.

Sequence variation in the human genome has been used as a tool in studying human diseases and the evolutionary history of man. A human inherited predisposition to tuberculosis has been suggested and studied; however. genetic mechanisms are still ambiguous. In the present study, we scanned the regulatory and coding region of Nuclear LIM Interactor-Interacting Factor gene (NLI-IF), which is physically close to the tuberculosis-associated gene NRAMP1. Thirteen biallelic single-nucleotide polymorphisms (SNPs) were identified from four ethnic populations (African-American, Caucasian, Hispanic, and Asian) with population-specific distribution of alleles. The extent of linkage disequilibrium (LD) between 402T > C, and 472-42G > A varied distinctly from complete LD in the non-African-American groups to strong but incomplete LD in African-Americans. Both SNPs were in significant LD with the polymorphism 3' UTR in NRAMP1 among these ethnic groups (P < 0.02), except 402T > C in African-Americans. In a case-control study with a Caucasian population, three cosmopolitan SNPs (204C > A, 402T > C and 472 - 42G > A) in NLI-IF showed no significant association with human susceptibility to tuberculosis. Our results support the "out-of-Africa" model of human origin, and suggest the time for the common ancestor dispersing from Africa could not have been more than approximately 385,620 years ago.

Race and Three Models of Human Origin

The future of the race concept depends in part upon the interpretations made of the molecular, biochemical, and anatomical evidence for the recent origins of Homo sapiens. Evidence of the decline of the concept among physical anthropology professors and in texts and research publications is presented, along with four reasons for the change. Three models regarding recent human origins are reviewed, each of which uses race as a descriptive term for a population aggregate. Each model carries implications that could strengthen or weaken the racial interpretation of human origins and the race concept. The phylogenetic status of Homo erectus outside of Africa is contingent in part upon the outcome of this debate.

Expression of preprodynorphin in human small cell lung carcinoma cell lines

The expression of preprodynorphin has been studied using the Northern blot technique. Ten human cell lines, six small cell lung carcinoma (SCLC), one large cell carcinoma (LCC), two neuroblastoma and one lymphoblast-like cell line, were screened with a preprodynorphin cRNA-probe. Tryptic digestion followed by radioimmunoassay for Leu-enkephalin-Arg 6 was used to detect possible translation of the preprodynorphin transcript. Of the ten cell lines investigated we found that all expressed preprodynorphin-mRNA to various degrees, and that this transcript is also translated. Two of the cell lines, neuroblastoma SK-N-MC and SCLC H69, also expressed preproenkephalin-mRNA. This set of cell lines provides a useful model of human origin in which the regulation of the preprodynorphin gene and the posttranslational processing of its products can be studied and compared.