Reconstructing the history of marriage and residence strategies in Indo-European-speaking societies

This file provides additional information on the data and methods used in Fortunato (2011a, b), and discussion of the results of the fossilization of nodes Proto-Indo-Hittite (PIH) and Proto-Indo-European (PIE) for marriage and residence strategies.     

Reconstructing the history of residence strategies in Indo-European-speaking societies: neo-, uxori-, and virilocality

Linguists and archaeologists have used reconstructions of early Indo-European residence strategies to constrain hypotheses about the homeland and trajectory of dispersal of Indo-European languages; however, these reconstructions are largely based on unsystematic and a historical use of the linguistic and ethnographic evidence, coupled with substantial bias in interpretation. Here I use cross-cultural data in a phylogenetic comparative framework to reconstruct the pattern of change in residence strategies in the history of societies speaking Indo-European languages. The analysis provides evidence in support of prevailing virilocality with alternative neolocality for Proto-Indo-European, and that this pattern may have extended back to Proto-Indo-Hittite. These findings bolster interpretations of the archaeological evidence that emphasize the "non-matricentric" structure of early Indo-European society; however, they also counter the notion that early Indo-European society was strongly "patricentric." I discuss implications of these findings in the context of the archaeological and genetic evidence on prehistoric social organization.     

Cooperative breeding and monogamy in mammalian societies

Comparative studies of social insects and birds show that the evolution of cooperative and eusocial breeding systems has been confined to species where females mate completely or almost exclusively with a single male, indicating that high levels of average kinship between group members are necessary for the evolution of reproductive altruism. In this paper, we show that in mammals, the evolution of cooperative breeding has been restricted to socially monogamous species which currently represent 5 per cent of all mammalian species. Since extra-pair paternity is relatively uncommon in socially monogamous and cooperatively breeding mammals, our analyses support the suggestion that high levels of average kinship between group members have played an important role in the evolution of cooperative breeding in non-human mammals, as well as in birds and insects.     

Coexistence of monogamy and polygyny in black-crested gibbon (Hylobates concolor)

All gibbons are monogamous and territorial with the exception ofHylobates concolor. This paper reports the coexistence of monogamy and polygyny in black-crested gibbons. Based on the fact of two adult females and two offspring of the same age category in one group and other reasons, we suppose that the two adult females have bred in a single group, i.e. a polygynous one. The other main reasons are: (1) a large home range makes it possible for more individuals to live in one group; (2) mutual tolerance among two females; and (3) selection pressure favouring polygyny.     

Adaptive advantages of monogamy in the great tit (Parus major): an experimental test of the polygyny threshold model

According to the polygyny threshold model, monogamy will prevail if variance in habitat quality is so small that females benefit from being monogramously paired in a poor habitat rather than being polygynously mated in a better habitat. This was tested in a monogamous territorial species, the great tit (Parus major), in two different habitats, viz. poor coniferous and rich deciduous forest by removing males in the latter. Widowed females fledged fewer young, and fledged young were lighter and had shorter tarsi compared to a control group in the deciduous forest indicating the importance of male assistance. Experimental broods were on average lighter than control broods in the deciduous forests which suggests that the polygyny threshold was not reached. No significant differences were found between control groups. Therefore, monogamy may prevail in the great tit because the difference between habitats is not of such a magnitude that polygyny would be advantageous for females.     

Reconstructing history: the Amazonian Mura Indians

We studied demographic characteristics of two Mura Indian villages. Two-hundred six inhabitants of these villages and another population were tested in relation to 30 blood and 4 saliva genetic systems. These groups exhibit high mobility and exogamy rates and high fertility but relatively low mortality and variance in number of children per woman. Hb J Oxford and albumin Maku were observed, and they show high prevalences of GPT*1 and RH*R1 but low of HP*1 compared to other South American Indians. Four electrophoretic saliva systems are reported here for the first time in a predominantly Amerindian group. The amount of polymorphism was more limited than that found in Caucasian, black, and Oriental populations. The Mura are still predominantly Indian (82%) but have African (11%) and Caucasoid (7%) admixture. Using these values, the putative ancestral Mura gene frequencies were assessed. Problems related to quantitative estimations of admixture and the factors that influence the process are discussed.     

Reconstructing the history of helminth prevalence in the UK

Intestinal helminth parasites (worms) have afflicted humans throughout history and their eggs are readily detected in archaeological deposits including at locations where intestinal parasites are no longer considered endemic (e.g. the UK). Parasites provide valuable archaeological insights into historical health, sanitation, hygiene, dietary and culinary practices, as well as other factors. Differences in the prevalence of helminths over time may help us understand factors that affected the rate of infection of these parasites in past populations. While communal deposits often contain relatively high numbers of parasite eggs, these cannot be used to calculate prevalence rates, which are a key epidemiological measure of infection. The prevalence of intestinal helminths was investigated through time in England, based on analysis of 464 human burials from 17 sites, dating from the Prehistoric to Industrial periods. Eggs from two faecal-oral transmitted nematodes (Ascaris sp. and Trichuris sp.) and the food-derived cestodes (Taenia spp. and Diphyllobothrium latum syn Dibothriocephalus latus) were identified, although only Ascaris was detected at a high frequency. The changing prevalence of nematode infections can be attributed to changes in effective sanitation or other factors that affect these faecal-oral transmitted parasites and the presence of cestode infections reflect dietary and culinary preferences. These results indicate that the impact of helminth infections on past populations varied over time, and that some locations witnessed a dramatic reduction in parasite prevalence during the industrial era (18^th-19^th century), whereas other locations continued to experience high prevalence levels. The factors underlying these reductions and the variation in prevalence provide a key historical context for modern anthelmintic programs.     

The influence of nest predation on mating strategies under polygyny

The mating status of an advertising male is one important factorfor female assessment. In species where already-mated malestry to attract additional females at some distance from theirmate, mating status may be difficult to assess. Limitationsin the time available to breed and a decrease in reproductivesuccess over the breeding season could make the costs outweighthe benefits of a time-consuming mate assessment process, whichautomatically postpones the onset of breeding. Time and energyconstraints will then limit the behavioral options for femalesin search of breeding opportunities, and females would suffera cost when assessing male mating status. Female choice maythen be better understood by analyzing the behavioral optionsfor females; the success of a strategy in which costly assessmentsare avoided and females choose mates indiscriminately, disregardingmating status ("fast" strategy), could be compared to the successof a strategy in which females carefully try to assess matingstatus ("coy" strategy). Nest predation should be included insuch an analysis because it influences the amount of male assistancefemales of polygynous males receive, as nest predation for onlyone of a polygynous male's two females leads to more male assistancefor the other female. In this study, I compare the outcome ofa "fast" strategy with that of a "coy" strategy under differentrates of nest predation. Although high probabilities of becominga mate of a polygynous male associated with a fitness reductiondecrease the relative success of a "fast" strategy, simulationsshow that high rates of nest predation considerably lower thedifference in the outcome of the two strategies. Therefore,the cost of assessing mating status must be relatively smallto be economical.     

Reconstructing life history of hominids and humans

Aspects of life history, such as processes and timing of development, age at maturation, and life span are consistently associated with one another across the animal kingdom. Species that develop rapidly tend to mature and reproduce early, have many offspring, and exhibit shorter life spans (r-selection) than those that develop slowly, have extended periods of premature growth, mature later in life, reproduce later and less frequently, have few offspring and/or single births, and exhibit extended life spans (K-selection). In general, primates are among the most K-selected of species. A suite of highly derived life history traits characterizes humans. Among these are physically immature neonates, slowed somatic development both in utero and post-natally, late attainment of reproductive maturity and first birth, and extended post-mature survival. Exactly when, why, and through what types of evolutionary interactions this suite arose is currently the subject of much conjecture and debate. Humankind's biocultural adaptations have helped to structure human life history evolution in unique ways not seen in other animal species. Among all species, life history traits may respond rapidly to alterations in selective pressures through hormonal processes. Selective pressures on life history likely varied widely among hominids and humans over their evolutionary history. This suggests that current patterns of human growth, development, maturation, reproduction, and post-mature survival may be of recent genesis, rather then long-standing adaptations. Thus, life history patterns observed among contemporary human and chimpanzee populations may provide little insight to those that existed earlier in hominid/human evolution.     

Reconstructing the duplication history of tandemly repeated genes

We present a novel approach to deal with the problem of reconstructing the duplication history of tandemly repeated genes that are supposed to have arisen from unequal recombination. We first describe the mathematical model of evolution by tandem duplication and introduce duplication histories and duplication trees. We then provide a simple recursive algorithm which determines whether or not a given rooted phylogeny can be a duplication history and another algorithm that simulates the unequal recombination process and searches for the best duplication trees according to the maximum parsimony criterion. We use real data sets of human immunoglobulins and T-cell receptors to validate our methods and algorithms. Identity between most parsimonious duplication trees and most parsimonious phylogenies for the same data, combined with the agreement with additional knowledge about the sequences, such as the presence of polymorphisms, shows strong evidence that our reconstruction procedure provides good insights into the duplication histories of these loci.     

On the evolution of polygyny: a theoretical examination of the polygyny threshold model

The polygyny threshold model states that if costs incurred areless than the benefits gained from mating polygynously in termsof breeding-situation quality, then polygyny is favored andcould evolve. We constructed mathematical models and computersimulations to evaluate this hypothesis. In the basic model,there is a single locus with two alleles, which regulates whetherthe female is receptive to polygyny. There are two breedingsituations of differing quality on which males randomly assort.Females then select a mate based on the associated breedingsituation and whether the male already has mates. This basicmodel is extended mathematically to include a cost for the initialfemale of a male with multiple mates and again to include geneexpression in males. The computer simulations extend the basicmodel to multiple loci and alleles and to multiple breedingsituations. The results presented here suggest that the polygynythreshold model is valid in a population genetic context: ifthe fitness of females that actually mate polygynously is greaterthan the fitness of monogamous females on poorer breeding situations,polygyny evolves. However, this approach reveals interestingdynamics not apparent from the verbal model. If the trait isexpressed in males and females, then polygyny can evolve evenif females mating polygynously have a lower fitness than femalesmating monogamously. In the multiple breeding-situations model,the polygyny allele increases to some equilibrium value abovewhich it experiences no selection. Surprisingly, as the costof polygyny increases, the equilibrium frequency of the polygynyallele also increases. The difference between this evolutionarymodel and the ideal free distribution is discussed.     

Reconstructing the history of log-drifting in the Reichraminger Hintergebirge, Austria

The watersheds of the rivers Enns and Steyer border the Reichraminger Hintergebirge. This area has a long tradition in the iron processing industry. Because mineral coal was not available, charcoal has been produced for the iron industry for the past 500 years, leading to a heavy exploitation of the vast forests (180 km²).

From the logging sites in the mountains the timber had to be transported up to 12 km to the forges in the lowland. Most of the small rivers had insufficient water to drift logs efficiently. Therefore, at gorges or at places where there were narrow steep sided valleys wooden dams (klausen) were built to block the water, using the first cut trees of a newly targeted harvesting area. By abruptly opening the dams, the rapid flow of the raised water level carried the logs to the next klausen. Up to seven klausen were built in a valley before the rechen (rake-like grids within the river to collect the logs) of the Enns and Steyer were reached.

To reconstruct the history of log drifting in the Reichraminger Hintergebirge, 33 klausen and rechen were visited and dendrochronologically sampled. The remaining wood of the dam constructions showed progressive stages of degradation, and in some cases only a few logs remained preserved under the water. With cores from living trees added to the dataset, master chronologies were established for spruce (576 years), fir (569 years) and larch (342 years). The construction history of the klausen can be sequentially traced back to 1563 AD. The time spans of the individual chronologies varied between 40 and 392 years. All available conifer species were utilized to build the dams, except during the 19th century, when the most suitable species - larch - was used to a higher degree.     

Reconstructing the history of selection during homoploid hybrid speciation

This study aims to identify selection pressures during the historical process of homoploid hybrid speciation in three Helianthus (sunflower) hybrid species. If selection against intrinsic genetic incompatibilities (fertility selection) or for important morphological/ecological traits (phenotypic selection) were important in hybrid speciation, we would expect this selection to have influenced the parentage of molecular markers or chromosomal segments in the hybrid species' genomes. To infer past selection, we compared the parentage of molecular markers in high-density maps of the three hybrid species with predicted marker parentage from an analysis of fertility selection in artificial hybrids and from the directions of quantitative trait loci effects with respect to the phenotypes of the hybrid species. Multiple logistic regression models were consistent with both fertility and phenotypic selection in all three species. To further investigate traits under selection, we used a permutation test to determine whether marker parentage predicted from groups of functionally related traits differed from neutral expectations. Our results suggest that trait groups associated with ecological divergence were under selection during hybrid speciation. This study presents a new method to test for selection and supports earlier claims that fertility selection and phenotypic selection on ecologically relevant traits have operated simultaneously during sunflower hybrid speciation.     

Reconstructing the evolutionary history of polyploids from multilabeled trees

In recent studies, phylogenetic networks have been derived from so-called multilabeled trees in order to understand the origins of certain polyploids. Although the trees used in these studies were constructed using sophisticated techniques in phylogenetic analysis, the presented networks were inferred using ad hoc arguments that cannot be easily extended to larger, more complicated examples. In this paper, we present a general method for constructing such networks, which takes as input a multilabeled phylogenetic tree and outputs a phylogenetic network with certain desirable properties. To illustrate the applicability of our method, we discuss its use in reconstructing the evolutionary history of plant allopolyploids. We conclude with a discussion concerning possible future directions. The network construction method has been implemented and is freely available for use from http://www.uea.ac.uk/ approximately a043878/padre.html.     

A new sociobiological theory of homosexuality applicable to societies with universal marriage

Several sociobiological theories have tried to explain human homosexuality. Adaptationally orthodox theories view it as a specific instance of reproductive altruism, in which the homosexual orientation in combination with a cross-gender identity is the emotional motivator of a nonreproductive role, leading to higher inclusive fitness for the individual displaying the trait in a particular environment. The nonreproduction is typically assumed to be plete—a large reproductive sacrifice. A new model is proposed in which human homosexuality remains a reproductively altruistic, trait, but in which the magnitude of the altruism is much reduced, and so presumably is more likely to result in a net increase in inclusive fitness. The theory applies to societies in which social pressures require marriage of essentially all reproductively able individuals, and does not require gender nonconformity. Hence, the new theoy fills some of the gaps left by the earlier orthodox theories, and in combination with them offers a consolidated set of hypothesis for testing.     

Reconstructing the introduction history of an invasive fish predator in South Africa

The Largemouth Bass (Micropterus salmoides) is a global invader with demonstrated ecological impacts on native fish communities. Introductions of fishes in freshwater ecosystems are often characterized as complex processes, yet an understanding of the nature of the introduction can inform management and conservation actions. Early in the twentieth century, two introductions of Largemouth Bass were made into South Africa for the establishment of a recreational fishery, and subsequent translocations have expanded their distribution to include much of southern Africa. In this study we quantified neutral genetic variation, modeled potential introduction scenarios, and identified potential source regions from within the native range. We documented limited levels of genetic diversity in nuclear microsatellite genotypes across populations (mean allelic richness = 1.80 and mean observed heterozygosity = 0.16) and observed low levels of genetic differentiation among four of the five focal populations (mean pairwise fixation index = 0.09), with a fifth population displaying greater levels of genetic divergence (mean pairwise fixation index = 0.27). A total of three cytochrome b haplotypes were recovered from South Africa samples and the single most common haplotype (93% of individuals) was identical to a haplotype from a population of Largemouth Bass in Maryland, USA. Using limited available stocking data along with outputs from Principal Component Analysis and approximate Bayesian evaluation of competing introduction scenarios we confirm the presence of multiple introductions. Despite evidence for multiple introductions, Largemouth Bass in South African water bodies harbor extremely low neutral genetic diversity, suggesting that even a very limited number of propagules can experience a high likelihood of success in invading nonnative waters.