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PubMed2003

The evolution of altruistic punishment.

Both laboratory and field data suggest that people punish noncooperators even in one-shot interactions. Although such "altruistic punishment" may explain the high levels of cooperation in human societies, it creates an evolutionary puzzle: existing models suggest that altruistic cooperation among nonrelatives is evolutionarily stable only in small groups. Thus, applying such models to the evolution of altruistic punishment leads to the prediction that people will not incur costs to punish others to provide benefits to large groups of nonrelatives. However, here we show that an important asymmetry between altruistic cooperation and altruistic punishment allows altruistic punishment to evolve in populations engaged in one-time, anonymous interactions. This process allows both altruistic punishment and altruistic cooperation to be maintained even when groups are large and other parameter values approximate conditions that characterize cultural evolution in the small-scale societies in which humans lived for most of our prehistory.

Journal Article↗
PubMed1986

A contribution to the geographical interpretation of biological change.

"Geography" has traditionally been assigned the role of handmaiden in evolutionary studies. In this work a different understanding of the relationship between biological change and locational setting is developed: evolution as a dynamic form of spatial interaction. In the causal model presented, adaptive change is portrayed as a negative feedback response contributing to a general spatial-temporal process of resource cycle tightening involving exchanges between the two fundamental structural sectors ("abiotic" and "biotic") of the earth's surface system. As such, it is rejected as "evolution" per se. This position makes it possible to circumvent the "adaptation yields adaptation" circularity, and to view locational circumstances as being evolutionarily causal, yet not deterministic with respect to population-level change. A parallel interpretation of the relation between range and range change and evolution is also implicit; the individualistic hypothesis is thereby superceded by a model of community evolution allowing for individualistic rates of population (adaptive and) range change, but operating on the principle that populations should tend to change range in common directions (as a response to spatially-varying degrees of efficiency of turnover of resources vital to biotic sector function). This in turn leads to the possibility of normative biogeographic modelling. Comment is also made on the relationship of the present understanding to disequilibrium and dynamic equilibrium interpretations of evolutionary change, and to human cultural evolution.

Animals↗
PubMed2006

Understanding cellular networks to improve hematopoietic stem cell expansion cultures.

Efforts to develop culture technologies capable of eliciting robust human blood stem cell growth have met with limited success. Considering that adult stem cell cultures are complex systems, comprising multiple cell types with dynamically changing intracellular signalling environments and cellular compositions, this is not surprising. Typically treated as single-input single-output systems, adult stem cell cultures are better described as complex, non-linear, multiple-input multiple-output systems wherein the proliferation of subpopulations of cells leads to the formation of intercellular endogenously secreted protein interaction networks. Genomic and proteomic tools need to be applied to generate high-throughput (and ideally high-content) biological measurements of stem cell culture evolution. Datasets describing cellular interaction networks need to be integrated into predictive models of in vitro stem cell development. Ultimately, such models will serve as a starting point for the rational design of blood stem cell expansion bioprocesses utilizing dynamic system perturbations to achieve the preferential expansion of target cell populations.

Cell Culture Techniques↗
PubMed2005

Ecological adaptation and species recognition drives vocal evolution in neotropical suboscine birds.

Given that evolutionary divergence in mating signals leads to reproductive isolation in numerous animal taxa, understanding what drives signal divergence is fundamental to our understanding of speciation. Mating signals are thought to diverge via several processes, including (1) as a by-product of morphological adaptation, (2) through direct adaptation to the signaling environment, or (3) to facilitate species recognition. According to the first two hypotheses, birdsongs diversify in different foraging niches and habitats as a product of selection for optimal morphology and efficient sound transmission, respectively. According to the third hypothesis, they diversify as a result of selection against maladaptive hybridization. In this study I test all three hypotheses by examining the influence of morphology, acoustic environment, and the presence of closely related congeners on song structure in 163 species of antbird (Thamnophilidae). Unlike oscine passerines, these Neotropical suboscines make ideal subjects because they develop their songs without learning. In other words, patterns of vocal divergence are not complicated by cultural evolution. In support of the morphological adaptation hypothesis, body mass correlates with the acoustic frequency of songs, and bill size with temporal patterning. These relationships were robust, even when controlling for phylogenetic inertia using independent contrasts, suggesting that there has been correlated evolution between morphological and acoustic traits. The results also support the acoustic adaptation hypothesis: birds which habitually sing in the understory and canopy produce higher-pitched songs than those that sing in the midstory, suggesting that song structure is related to the sound transmission properties of different habitat strata. Finally, the songs of sympatric pairs of closely related species are more divergent than those of allopatric pairs, as predicted by the species recognition hypothesis. To my knowledge, these data provide the first direct evidence that species recognition and ecological adaptation operate in tandem, and that the interplay between these factors drives the evolution of mating signals in suboscine birds.

Acoustics↗
PubMed2006

Second site escape of a T20-dependent HIV-1 variant by a single amino acid change in the CD4 binding region of the envelope glycoprotein.

BACKGROUND: We previously described the selection of a T20-dependent human immunodeficiency virus type-1 (HIV-1) variant in a patient on T20 therapy. The fusion inhibitor T20 targets the viral envelope (Env) protein by blocking a conformational switch that is critical for viral entry into the host cell. T20-dependent viral entry is the result of 2 mutations in Env (GIA-SKY), creating a protein that undergoes a premature conformational switch, and the presence of T20 prevents this premature switch and rescues viral entry. In the present study, we performed 6 independent evolution experiments with the T20-dependent HIV-1 variant in the absence of T20, with the aim to identify second site compensatory changes, which may provide new mechanistic insights into Env function and the T20-dependence mechanism. RESULTS: Escape variants with improved replication capacity appeared within 42 days in 5 evolution cultures. Strikingly, 3 cultures revealed the same single amino acid change in the CD4 binding region of Env (glycine at position 431 substituted for arginine: G431R). This mutation was sufficient to abolish the T20-dependence phenotype and restore viral replication in the absence of T20. The GIA-SKY-G431R escape variant produces an Env protein that exhibits reduced syncytia formation and reduced cell-cell fusion activity. The escape variant was more sensitive to an antibody acting on an early gp41 intermediate, suggesting that the G431R mutation helps preserve a pre-fusion Env conformation, similar to T20 action. The escape variant was also less sensitive to soluble CD4, suggesting a reduced CD4 receptor affinity. CONCLUSION: The forced evolution experiments indicate that the premature conformational switch of the T20-dependent HIV-1 Env variant (GIA-SKY) can be corrected by a second site mutation in Env (GIA-SKY-G431R) that affects the interaction with the CD4 receptor.

Amino Acid Sequence↗
PubMed2000

Viral diseases and human evolution.

The interaction of man with viral agents was possibly a key factor shaping human evolution, culture and civilization from its outset. Evidence of the effect of disease, since the early stages of human speciation, through pre-historical times to the present suggest that the types of viruses associated with man changed in time. As human populations progressed technologically, they grew in numbers and density. As a consequence different viruses found suitable conditions to thrive and establish long-lasting associations with man. Although not all viral agents cause disease and some may in fact be considered beneficial, the present situation of overpopulation, poverty and ecological inbalance may have devastating effects on human progress. Recently emerged diseases causing massive pandemics (e.g., HIV-1 and HCV, dengue, etc.) are becoming formidable challenges, which may have a direct impact on the fate of our species.

Biological Evolution↗
PubMed2000

A comprehensive karyotypic analysis on a newly developed hepatocellular carcinoma cell line, HKCI-1, by spectral karyotyping and comparative genomic hybridization.

A continuously growing human hepatocellular carcinoma (HCC) cell line was established from a Chinese male, carrier of the hepatitis B virus (HBV). This cell line, designated HKCI-1, grows as an adhering monolayer of polygonal epithelial cells that embody one or more nuclei. HKCI-1 secretes alpha-fetoprotein but shows no evidence of HBV carriage. Conventional banding analysis of the short-term cultured primary tumor and the propagated HKCI-1 revealed a chromosome modal number of near-triploidy. It was, however, impossible to derive their complete karyotype due to the complex nature of chromosomal rearrangements and many marker chromosomes of uncertain origin. Spectral karyotyping (SKY) is a newly developed molecular cytogenetic technique that allows the unprecedented discernment of chromosomal abnormalities. Spectral karyotyping analysis on HKCI-1 and the primary tumor elucidated all aberrant chromosomes and revealed complex karyograms. Recurring aberrations detected in both primary tumor and HKCI-1 included der(X)t(X;11)(q10;p10), der(1)t(1;10)(q10;?pq), der(4)t(4;16)(p10;q10), i(5p), del(5)(q13), der(7)t(7;21)(q32q10::q10), der(8)t(8;17)(q10;p10), and der(9)t(9;22)(q34;?pq). Comparative genomic hybridization (CGH) was employed to monitor the culture evolution in vitro. Genomic imbalances in HKCI-1 involved chromosomal losses on 4q, 5q13-qter, 8p, 9pter-q33, 10q, 11q, 13q, 16q, 17q12-qter, and 22, and low-level gains on 6pter-q22, 7p, 8q, 9q34, 10p, 11p, 12, 17pter-q11.2, 18, 19, 20, 21, and Y. High-level amplifications were also detected on 5pter-q12, 7q11.2-qter, and Xq. The corresponding CGH finding on the primary tumor indicated similar imbalances. TP53 mutational analysis showed that both HKCI-1 and the primary tumor had the aflatoxin-associated mutation in codon 249 and an additional TP53 polymorphism in codon 72. Our present study demonstrates the value of combined SKY and CGH study in defining complex rearrangements and identifying cryptic translocations, and provides a comprehensive analysis on the chromosomal abnormalities in HKCI-1.

Adult↗
PubMed1981

The HLA loci of th Hopi and Navajo.

The purpose of this paper is to present the genetic distribution at the HLA-A, B, C, and DR loci in the Hopi and the Navajo. A sample of 100 out-patients from each tribe was selected at the Public Health Service Indian Hospital in Keam's Canyon, Arizona, and was typed for the antigens at the four loci. The distributions of the alleles and the haplotypes are similar in each tribe. A distance measure, f, confirms the genetic similarity of the two populations. It is concluded that the great cultural diversity of the Hopi and the Navajo is the result of a cultural evolution and diversification that has greatly outstripped the genetic evolution at the major histocompatibility loci over the past 20,000 years.

Arizona↗
PubMed1984

Structural changes in the femur with the transition to agriculture on the Georgia coast.

Structural characteristics of the femur are compared in preagricultural (2200 B.C.-A.D. 1150) and agricultural (A.D. 1150-1550) subsistence strategy groups from the Georgia coast. Using an automated technique, cross-sectional geometric properties used in structural analyses (areas, second moments of area) were determined at midshaft and distal to the lesser trochanter in 20 adults from each group. A significant decline in magnitude of almost every geometric property occurs in the agricultural group. The differences between groups are reduced but still significant for many properties after standardizing for bone length differences. In addition, a remodeling of the femoral cortex to one of relatively smaller medullary and subperiosteal diameter, as well as a more circular cross-sectional shape, is characteristic of agricultural femora. Thus, while the relative cross-sectional area of bone remains the same, the spatial distribution of bone area is different in the two groups. The results strongly suggest a relative reduction in mechanical loadings of the femur in the agricultural group, implying different levels and possibly types of activity involving the lower limb in the two groups. The data are also compared with similar data available for the Pecos Pueblo (agricultural) sample. The comparison indicates that types of activity may have been more similar in the two agricultural samples, but that general levels of activity were more similar in the Pecos Pueblo and Georgia coast preagricultural samples.

Agriculture↗
PubMed1985

Genetic variation in North Amerindian populations: association with sociocultural complexity.

A survey of nine polymorphic loci for 82 North Amerindian populations was undertaken to test the hypothesis that increasing levels of sociocultural complexity are ineluctably accompanied by increased heterozygosity. The data reveal a significant relationship in the predicted direction. Moreover, the significant correlation between average heterozygosity and sociocultural complexity is substantially increased by the removal of 19 highly admixed samples. However, this relationship, at least among North Amerindian populations, may be more apparent than real since both mean heterozygosity and the level of sociocultural organization are significantly negatively correlated with latitude. When this latter variable is controlled for, all correlations between heterozygosity and sociocultural complexity are rendered nonsignificant.

Cultural Characteristics↗
PubMed2002

Evolutionary health promotion.

Health promotion's promise is enormous, but its potential is, as yet, unmatched by accomplishment. Life expectancy increases track more closely with economic prosperity and sanitary engineering than with strictly medical advances. Notable achievements in the past century--the decreased incidences of epidemic infections, dental caries, and stomach cancer--are owed to virologists, dentists, and (probably) refrigeration more than to physicians. Prevention speaks against tobacco abuse with a single voice, but in many other areas contradictory research findings have generated skepticism and even indifference among the general public for whom recommendations are targeted. Health promotion's shortcomings may reflect lack of an overall conceptual framework, a deficiency that might be corrected by adopting evolutionary premises: (1) The human genome was selected in past environments far different from those of the present. (2) Cultural evolution now proceeds too rapidly for genetic accommodation--resulting in dissociation between our genes and our lives. (3) This mismatch between biology and lifestyle fosters development of degenerative diseases. These principles could inform a research agenda and, ultimately, public policy: (1) Better characterize differences between ancient and modern life patterns. (2) Identify which of these affect the development of disease. (3) Integrate epidemiological, mechanistic, and genetic data with evolutionary principles to create an overarching formulation upon which to base persuasive, consistent, and effective recommendations.

Biological Evolution↗
PubMed1981

Structure and anti-structure in the culture-bound syndromes: The Malay case.

Turner's concepts of structure and anti-structure are applied to the culture-bound syndromes to demonstrate that they are dialectical aspects of cultural reality, The Malay cases of amok, latah and possession hysteria are discussed as instances of anti-structural behaviors that dramatize role-reversals and role-enhancement. The performers of these behaviors are not subjected to the Malay code of moral conduct. The supernatural ethos in Malay culture plays an important role in shaping tolerance towards them. Although this tolerance has been gradually eroded as a result of the introduction of Western psychiatry, the anti-structural status of these syndromes has not faded away but has assumed new meanings in terms of psychopathology.

Cultural Characteristics↗
PubMed1980

[The profile direction toward right and left as seen from a historical study of cultural development. A dominance problem (author's transl)].

Eighty percent of right handers drawing a human profile, direct it towards the left. The neurophysiological basis for this fact and the dominant role that the right hemisphere plays in higher visual performances is discussed. The preference for the left profile direction is traced back to the early Greek period in paintings, drawings, coin portraits, gems, cameos, and vase portraits. Fifty thousand objects have been analyzed. A 60% prevalence of face direction towards the right occurs in the cultural centers of the Mediterranean before 600 B.C. Before the early Greek period: the Assyrian, Egyptian, and Sumerian cultures faced more profiles to the right. This tendency for right profile direction can be traced back to Stone Age cave drawings. The profile shift from right to left occurs in the early Greek period and is related to a shift in script and in letter profile at the same time. This profile shift occurs simultaneously with an acceleration of intellectual and cultural development which also influenced our present culture. Although the percentage of right handers might not have changed considerably since the Stone Age, the profile shift from right to left suggests a hypothetical change in dominance of the cerebral hemispheres for the higher visual perception which may have induced a left preference in the period around 600 B.C.

Art↗
PubMed1995

The impact of culture on human and space development--new millennial challenge.

The Space Age is causing new applications to the concept of culture, a human coping tool. The exploration and exploitation of outer space resources are altering human culture both on Earth and in orbit. For the first time in history, our species need not merely react and adapt to environment, but plan for a space culture appropriate for extraterrestrial migration. The impact of culture can be analyzed in terms of how space developments alter human perceptions and behavior on this planet; the emergence of a new culture to suit the orbital environment; the organizations that build spacecraft and deploy people aloft; and the technological systems created for spacefaring. This article presents a paradigm for analyzing some of the non-technical human factors involved in space undertakings. It also offers a method for classifying a culture according to ten categories which may be applied both to a macroculture, such as a lunar base; or a microculture, such as a space agency or crew. Human enterprise in space is viewed as both altering the species, and providing a challenge for expanded behavioral and biological scientific research on living and working in space.

Adaptation, Psychological↗
PubMed1983

Sex differences in human mortality: the role of genetic factors.

This paper reviews evidence concerning genetic factors that influence sex differences in human mortality, with attention to the interactions between genetic and environmental factors. Some widely quoted earlier conclusions, for example, that males have consistently higher fetal mortality than females, are not supported by current evidence. For example, for late fetal mortality, males had higher rates than females in earlier historical data, but not in recent data for several advanced industrial countries. This reflects a changing balance between an inherently greater female vulnerability for one major type of late fetal mortality and inherently greater male vulnerability for several other types of late fetal mortality that have declined in importance as health care has improved. Males appear to be inherently more vulnerable than females to infant mortality, although the causes of this vulnerability are poorly understood. X-linked immunoregulatory genes appear to contribute to greater female resistance to infectious diseases. Despite these apparent inherent advantages for females, in some situations females have had higher infant mortality and higher infectious disease mortality than males, apparently due to environmental disadvantages for females, such as less adequate diet and health care. Inherent sex differences in reproductive physiology and anatomy contribute to higher female mortality for breast cancer and maternal mortality. For these causes of death, as for the other categories discussed, the death rates and thus the contributions to sex differences in total mortality vary considerably depending on environmental conditions. Several hypothesized contributions of sex hormones to sex differences in mortality are at present controversial due to contradictions and limitations in the available data. There may be effects of male sex hormones on sex differences in behavior which contribute to males' higher death rates for accidents and other violent causes. Women's endogenous sex hormones may reduce women's risk of ischemic heart disease. For both violent deaths and ischemic heart disease it appears that any genetic contributions to sex differences in mortality are strongly reinforced by the cultural influences that foster more risky behavior in males, including more use of weapons, employment in hazardous occupations, heavy alcohol consumption and cigarette smoking. It appears that these cultural influences on sex differences in behavior are widespread cross-culturally in part because of the effects of inherent sex differences in reproductive functions on the cultural evolution of sex roles. These examples illustrate the complexity and importance of interactions between genetic and environmental factors in determining sex differences in human mortality.

Accidents↗
PubMed1984

The buccra-massa and the little man's broker in a Jamaican sugartown: implications for community health education.

In societies that have been historically stratified by class, interclass communication is frequently hampered by behaviors of higher status people that lower status people interpret as denigrating. To escape what they perceive as denigration, lower status people may attempt to avoid interclass interaction, and, when it is unavoidable, adopt such strategies as not making direct eye contact, saying very little except what they think the higher status people want to hear (including flattery), and using a lower status peer as an intermediary. Such behavioral patterns have important implications for the design of health services programs. This paper presents a case study of such interaction difficulties observed during 13 months of anthropological research in a Jamaican town. The lower status people in the town of Haversham (a pseudonym) refer to this avoidance behavior as the 'buccra-massa'. The antonym of buccra-massa is 'buck-the-massa'. 'Buck-the-massa' is characterized by being able to look higher status people in the eye and boldly engage them in conversation. Lower status persons who are known for bucking the massa are frequently used as intermediaries in cross-class interactions. Because Havershamians refer to higher status men as 'big men' and to lower status men as 'little men', the author calls the intermediaries used by lower status people in Haversham, 'little man's brokers'. The author argues that the buccra-massa and buck-the-massa behavioral traditions had their roots in the complex and extreme social inequalities of the slavery period in Jamaica. It is further argued that economic difficulties in Jamaica since the slavery period have contributed to the persistence of these behavioral dynamics to the present day. The buccra-massa/buck-the-massa behavioral complex is often manifested in health care settings in Jamaica. Thus, the author suggests that the little man's broker can be very useful in promoting less threatening, and therefore more effective, interactions between the clients and the staff of health and other human service programs. He notes that while staffmembers often view brokering behavior as trouble making, many of the clients they wish to serve view this same behavior as bucking-the-massa. It is a mistake, according to this analysis, to ignore the little man's broker. As this case of Jamaica shows, accomplished brokers can choose to exert their extensive influence against utilization of services offered by specific programs.(ABSTRACT TRUNCATED AT 400 WORDS)

Communication↗