news aggregator

November 12, 2014

22:00
In the last two decades, models from evolutionary biology have made important contributions to demographic research on human fertility change. Within this evolutionary framework, two distinct traditions have focused on different processes of adaptation and time scales of change: (1) behavioral ecological perspectives have focused on how individual fertility decisions are shaped by local ecological circumstances, while (2) cultural evolutionary approaches have emphasized the role of socially transmitted information and changing social norms in shaping fertility behavior. While each tradition has made independent progress, research that integrates these approaches is necessary to improve our understanding of real fertility behavior, which results from a feedback between individual fertility decisions and social change. This approach requires combined attention to immediate ecological determinants of fertility decisions as well as the long-term processes that shape costs and benefits in a given environment. This workshop will bring together an international team of evolutionary behavioral scientists with complementary methodological and theoretical expertise in anthropology, psychology, and demography to develop (a) a synthetic article which proposes how these approaches can be integrated methodologically and theoretically, (b) an empirical article which applies our new synthetic framework to the study of fertility change in a particular fieldsite, demonstrating how the new methodological approach will work in practice and what we can learn through employing it, and (c) a multi-site grant proposal (UK, US, Bangladesh, Ethiopia, Bolivia, Poland) aimed at integrating and empirically testing these diverse evolutionary models of human fertility change.
Source: NESCent

November 2, 2014

22:00
Human cultural diversity is expressed in myriad ways (from social and marital norms to languages and religious practices), but what factors shape this diversity? Dating back to Darwin, multiple disciplines have debated the degree to which cultural diversity patterns are influenced by different factors, including history, demographics, and ecology. Over recent years an emerging set of studies have showcased how phylogenetic comparative methods from evolutionary biology can help resolve these long-held debates and revolutionize the field of cultural evolution. Now the major barrier to advances lies in the location of necessary data, which are spread across multiple disparate sources in linguistics, biogeography and anthropology. To overcome this challenge we will create D-PLACE (a Database of Phylogenies of Languages for the study of Cultural Evolution), a publicly available and expandable web-portal that will map over 100 cultural features onto language phylogenies and link these to ecological and environmental variables, empowering a whole new line of investigation into the drivers of cultural change and patterns of cultural diversity. We will produce a paper to introduce D-PLACE and outline the many types of questions in comparative anthropology the database can answer. Finally, we will demonstrate the power of this new resource by using D-PLACE to examine two long-standing and fundamental questions from comparative anthropology: (i) What drives the diversity of incest taboos (i.e. how human societies regulate who can mate and marry)? (ii) Can we characterize recurrent “human niches”, or are societies just arbitrary bundles of cultural features?
Source: NESCent

October 22, 2014

22:00
Why are some genes imprinted, where the maternally or paternally inherited copies are preferentially expressed? Ever since the paradoxical pattern of imprinted gene expression was discovered evolutionary theories have strived to answer this question. Consequently, theories built on different fundamental assumptions have proliferated. Although these theories should make distinct and testable predictions, there have been few tests aimed at formally differentiating between these competing ideas. However, despite the general lack of such tests, the ‘kinship theory’, and especially its most prominent component, the ‘conflict hypothesis’, has emerged as the favored theory. This predominance is most notably reflected in the literature outside of evolutionary biology, where the conflict hypothesis is regularly used to interpret the functions and effects of imprinted genes. The conflict hypothesis rose to dominance because it appears to explain the effects of the first imprinted genes discovered. However, data from a broader array of genes in model species and emerging insights from non-model species appear to challenge whether one hypothesis adequately explains all occurrences of imprinting. We propose a working group composed of theoretical, computational and empirical biologists that will develop a set of formal predictions and devise tests to differentiate between competing models for the evolution of genomic imprinting. In doing so, we also expect to identify unexplored problems in evolutionary theory. Understanding why genes are imprinted also has important implications for evolutionary medicine since imprinted genes play a crucial role during pregnancy, in the manifestation of several behavioral disorders, and in some cancers.
Source: NESCent

October 15, 2014

22:00
Underlying the adaptive behavior of animals is a process by which individuals must make decisions based on functionally relevant categories: who is a suitable mate, social partner, host, or prey item? Who is a competitor or a predator? Despite the ubiquitous need for animals to find a suitable mate, sort out enemies from collaborators, and correctly identify food, we lack a unifying framework of evolutionary decision theory. Here, we propose a cross-disciplinary team to establish an integrative conceptual framework with testable hypotheses for studying decision-making in an evolutionary context. Leveraging expertise from research programs in evolution, neurobiology, behavioral ecology, and comparative psychology, we aim to address questions of whether and how available information is processed by similar or different algorithms to generate decisions across individuals, species, sensory modalities, and functional contexts. We identify directions for immediate analyses within a new framework, including the role of learning and memory in shaping animal decisions, and hypotheses related to the evolution of categorical-like perception in a complex environment. We propose to systematically synthesize the primary literature incorporating data from behavioral “choice” and “recognition” trials (e.g., mate choice, host choice, kin recognition, parasite rejection), in order to generate a large, multi-taxon, publicly available database that will provide a rich source of data for future analyses of comparative patterns in decision making algorithms. Ultimately, our aim is to bring together a diversity of perspectives spanning multiple levels of analysis in order to transform our understanding of decision-making in an evolutionary context.
Source: NESCent

October 12, 2014

22:00
Sphagnum (peatmosses) dominate wetland ecosystems where they occur and are largely responsible for the structure and function of these ecosystems. Northern peatlands are estimated to harbor some 30% of the terrestrial carbon pool because they accumulate thick layers of partially decomposed plant material (peat). Because of their role in the global carbon cycle, peatmosses are crucial determinants of present and future climate. Sphagnum and peatlands have long served as a model for work on niche partitioning and community assembly. Simultaneously, the genus has become a focus for phylogenetic, biogeographic, and population genetic research. The Joint Genome Institute recently accepted our proposal to generate a genome sequence for a representative species of Sphagnum, along with complementary transcriptome analyses from plants grown under experimental treatments differing in nutrient, water, and temperature conditions. Previous research has shown that Sphagnum species differ in important functional traits that scale up to affect ecosystem-level processes. The availability of genomic data for Sphagnum provides an unprecedented opportunity to link comparative, structural and functional genomics with the evolution of whole-plant functional traits, and through these traits to global biogeochemistry and climate. Our proposed workshop will bring together inter-disciplinary representatives from the genomic sciences and molecular evolution, physiology, peatland ecology, and climate research. Our general goal is to assess what we know about peatmoss ecology and evolution, and what we need to know in order to leverage our genomic knowledge to develop an international research program focused on how evolution at multiple levels of biological organization scale up to impact ecosystem function and global climate.
Source: NESCent

October 8, 2014

22:00
In the last two decades, models from evolutionary biology have made important contributions to demographic research on human fertility change. Within this evolutionary framework, two distinct traditions have focused on different processes of adaptation and time scales of change: (1) behavioral ecological perspectives have focused on how individual fertility decisions are shaped by local ecological circumstances, while (2) cultural evolutionary approaches have emphasized the role of socially transmitted information and changing social norms in shaping fertility behavior. While each tradition has made independent progress, research that integrates these approaches is necessary to improve our understanding of real fertility behavior, which results from a feedback between individual fertility decisions and social change. This approach requires combined attention to immediate ecological determinants of fertility decisions as well as the long-term processes that shape costs and benefits in a given environment. This workshop will bring together an international team of evolutionary behavioral scientists with complementary methodological and theoretical expertise in anthropology, psychology, and demography to develop (a) a synthetic article which proposes how these approaches can be integrated methodologically and theoretically, (b) an empirical article which applies our new synthetic framework to the study of fertility change in a particular fieldsite, demonstrating how the new methodological approach will work in practice and what we can learn through employing it, and (c) a multi-site grant proposal (UK, US, Bangladesh, Ethiopia, Bolivia, Poland) aimed at integrating and empirically testing these diverse evolutionary models of human fertility change.
Source: NESCent

October 6, 2014

22:00
Evolutionary and ecological immunology is a multi-disciplinary topic in evolutionary biology. Considerable empirical attention has been paid to identifying the costs of mounting an immune response, determining whether immunity is sexually dimorphic, and elucidating how immunity is related to the expression of sexually selected traits across a variety of taxa. There is, however, little consensus on whether current hypotheses and predictions are supported. It is unclear if general patterns exist within and differ across taxa. Our NESCent working group intends to address these issues in three ways: (1) perform taxonomically-broad, phylogenetic meta-analyses to assess the support for hypotheses and predictions and to identify alternative explanations and new hypothese; (2) modify existing life history models to derive quantitative predictions about the relationship between immune function and key life history traits; (3) construct an open-access, updatable online database to facilitate further analyses relevant to evolutionary immunology.
Source: NESCent

October 5, 2014

22:00
Studies characterizing the composition of host-associated (mostly human) microbiota under different conditions, such as healthy or diseased state, age progression, contrasting diets, etc. have skyrocketed in the past 5 years. There is a growing recognition that host-associated, especially the gut-associated microbiota influences host metabolism, immune responses and overall wellbeing. Understanding how the community of gut microbes evolved and functions requires applying ecological and evolutionary principles. We propose to bring together evolutionary biologists, community ecologists, microbial ecologists and medical microbiologists to develop a synthesis of the existing studies and a roadmap to move the field forward. In particular, we aim to determine what evolutionary and ecological principles can be applied to the existing data and what new data need to be gathered to increase our understanding of the biotic interactions among the gut microbes and the host. To move from describing patterns to understanding the processes, we need to develop novel mechanistic frameworks. Eco-evolutionary trait-based approaches can be a useful framework to understand the role of competitive, mutualistic and other interactions in structuring microbiota and regulating functioning. So far, there has been little interaction across relevant disciplines and this may hinder our progress in understanding the microbiota-host interactions. This meeting will help break the disciplinary barriers, establish new collaborations and achieve synergy in the analysis and synthesis of the ecology and evolution of the host-associated microbiota.
Source: NESCent

September 28, 2014

22:00
Baker’s Law (hereafter BL) states that self-compatible organisms are more likely to be successful colonizers after long-distance dispersal than self-incompatible organisms. This simple prediction draws a link between mating-system evolution and diverse fields of ecology and evolution such as dispersal biology and colonization, the evolution of range size and range limits, demography and Allee effect, and invasion biology. However, after >60 years of experimental research and theory development, the accumulated data yield varying, and often contradictory, support of BL. Our working group brings together a diverse array of researchers to assess predictions and assumptions of BL and elucidate ecological, evolutionary, and demographic parameters likely to determine the relationships between mating system, dispersal, and colonization success. To accomplish these goals we will: 1) Compile the voluminous literature on BL. 2) Link the BL data with two extensive databases gathered by prior NESCent support (seed germination and seed traits data; mating system data) and a NCEAS pollen limitation database. These expanded databases will include dispersal, range size, and life-history traits, thereby creating a powerful tool for testing various aspects of the relationship between mating-system and colonization success. 3) Employ macroevolutionary tools to map mating-system and dispersal traits onto the angiosperm phylogeny to assess evolutionary patterns and phylogenetically-corrected trait correlations. 4) Formalize BL using current population genetic theory and dispersal theory. Synthetic products of our working group should elucidate the links between dispersal and mating-system in colonization success, and will influence multiple fields of research in evolution for the foreseeable future.
Source: NESCent
22:00
Baker’s Law (hereafter BL) states that self-compatible organisms are more likely to be successful colonizers after long-distance dispersal than self-incompatible organisms. This simple prediction draws a link between mating-system evolution and diverse fields of ecology and evolution such as dispersal biology and colonization, the evolution of range size and range limits, demography and Allee effect, and invasion biology. However, after >60 years of experimental research and theory development, the accumulated data yield varying, and often contradictory, support of BL. Our working group brings together a diverse array of researchers to assess predictions and assumptions of BL and elucidate ecological, evolutionary, and demographic parameters likely to determine the relationships between mating system, dispersal, and colonization success. To accomplish these goals we will: 1) Compile the voluminous literature on BL. 2) Link the BL data with two extensive databases gathered by prior NESCent support (seed germination and seed traits data; mating system data) and a NCEAS pollen limitation database. These expanded databases will include dispersal, range size, and life-history traits, thereby creating a powerful tool for testing various aspects of the relationship between mating-system and colonization success. 3) Employ macroevolutionary tools to map mating-system and dispersal traits onto the angiosperm phylogeny to assess evolutionary patterns and phylogenetically-corrected trait correlations. 4) Formalize BL using current population genetic theory and dispersal theory. Synthetic products of our working group should elucidate the links between dispersal and mating-system in colonization success, and will influence multiple fields of research in evolution for the foreseeable future.
Source: NESCent

September 21, 2014

22:00
Venom has evolved multiple times in the Metazoa, and shows a remarkable diversity in function, structure, and gene sequence across and within lineages. This diversity has both phylogenetic and functional components, reflecting the lineage of the organism producing the venom and the specific interactions between the venomous animal and its target. The proposed Catalysis Meeting will engage two scientific communities (evolutionary biologists and toxinologists) working on complementary aspects of venom and on diverse lineages of venom-producing organisms to synthesize, integrate, and coordinate future research on venom. The meeting will help participants recognize opportunities in venom biology and provide a forum to discuss effective ways to realize those opportunities. This meeting will further studies of venom evolution by: 1) discussing the generality of the current, snake-focused models; 2) identifying the kinds of biochemical, pharmacological, and protein data needed to address broad questions about venom evolution and ecology; and 3) using phylogenetic and ecological perspective to identify compelling novel study systems for cell and molecular investigation of venom. Participants will develop an integrated Roadmap for research into venom evolution to guide efforts over the next decade that will be disseminated via review articles and symposia targeted to audiences in toxinology and evolutionary biology. We also expect that this meeting will facilitate individual-level collaborations that lead to joint grant proposals and training.
Source: NESCent

September 1, 2014

22:00
This working group proposal wishes to bring together software engineers and biologists that - instead of addressing a particular evolutionary question – are proposing to design and implement the software that is essential in evolutionary genomics so that questions can be asked in the first place. Evolutionary and ecological functional genomics (EFFG) is the study - with the aid of genomic technologies - of ecology and evolution of ‘non-model species’. With Next Generation Sequencing (NGS), the grand challenge in evolutionary genomic science is no longer the generation of data but deciphering them. The capability to convert sequence data to knowledge is, however, still locked in the discipline of bioinformatics because the data forms are not suitable for processing by research biologists. We have two solutions: 1) train domain experts in basic data processing informatics and 2) develop Graphical User Interfaces (GUIs) to view and analyse EEFG data. We require a single platform that can facilitate mining, analysis and annotation of comparative data for genetics, ecology and genomics. It should be easy to setup and easier to use. It should be modular, with contributions from multiple labs. Because informaticians and software engineers are better at implementing rather than designing biological applications, this proposed working group will bring together i) professional curators; ii) informaticians and iii) comparative genomicists with the scope to a) form and implement a roadmap for teaching/importing biocuration practices into the field of comparative genomics b) delivering user-friendly software for the analysis and curation of data relevant to EEFG.
Source: NESCent
22:00
This working group proposal wishes to bring together software engineers and biologists that - instead of addressing a particular evolutionary question – are proposing to design and implement the software that is essential in evolutionary genomics so that questions can be asked in the first place. Evolutionary and ecological functional genomics (EFFG) is the study - with the aid of genomic technologies - of ecology and evolution of ‘non-model species’. With Next Generation Sequencing (NGS), the grand challenge in evolutionary genomic science is no longer the generation of data but deciphering them. The capability to convert sequence data to knowledge is, however, still locked in the discipline of bioinformatics because the data forms are not suitable for processing by research biologists. We have two solutions: 1) train domain experts in basic data processing informatics and 2) develop Graphical User Interfaces (GUIs) to view and analyse EEFG data. We require a single platform that can facilitate mining, analysis and annotation of comparative data for genetics, ecology and genomics. It should be easy to setup and easier to use. It should be modular, with contributions from multiple labs. Because informaticians and software engineers are better at implementing rather than designing biological applications, this proposed working group will bring together i) professional curators; ii) informaticians and iii) comparative genomicists with the scope to a) form and implement a roadmap for teaching/importing biocuration practices into the field of comparative genomics b) delivering user-friendly software for the analysis and curation of data relevant to EEFG.
Source: NESCent

August 19, 2014

22:00
Natural selection adapts organisms to their past environments and has no ability to foresee the future. When the environment changes, adaptations to past environments can misfire in the current environment, producing a mismatch that can only be solved by subsequent evolution or by modifying the current environment. Mismatches are an inevitable consequence of evolution in changing environments. They are especially relevant to human affairs, since modern human environments are so radically different from ancestral human environments. In addition, countless species are becoming mismatched to their environments thanks to anthropogenic environmental changes at a planetary scale. Waiting for subsequent genetic evolution to correct mismatches is not an option for problems requiring immediate solutions. This working group will develop a rigorous methodology for identifying evolutionary mismatches and finding the right environmental interventions, or “what to do about it,” in both humans and nonhuman species. The focus on mismatch emerged from the recent NESCent catalysis meeting titled “The Nature of Regulation: How Evolutionary Theory Can Inform the Regulation of Large-scale Human Social Interactions” which was organized in collaboration with the Evolution Institute. The working group will continue the collaboration, including a novel organizational structure that nests the working group within larger groups that provide both an informed audience and enables meaningful input from a distance.
Source: NESCent

August 16, 2014

22:00
This Working Group brings together paleontologists, K-12 science education specialists, and museum education staff to design and deliver innovative programming that uses fossils to engage students in explorations of evolutionary concepts. Students will investigate changes in biodiversity through time, test hypotheses of phylogenetic relationship, and examine the causes and consequences of mass extinctions, all using authentic fossil data. We will partner with local schools and community groups to share this programming with public school students in Chicago, Denver, and Philadelphia. Undergraduate and graduate students who are themselves under-represented minorities will serve as facilitators and mentors. Extensive pre- and post-assessment measures will allow us to measure prior understandings and attitudes and to evaluate learning gains. Research questions to be explored include comparing field-based vs. classroom-based learning, evaluating the use of 3D geospatial visualizations of biodiversity changes and extinctions through time, and measuring student gains in scientific reasoning skills.
Source: NESCent

August 11, 2014

22:00
Humans are vulnerable to a number of unique musculoskeletal maladies as a consequence of our evolutionary history. Although walking on our extended hind limbs is the hallmark adaptation characterizing our species it nevertheless makes us vulnerable to a wide range of serious joint and soft tissue problems. When viewed from an evolutionary perspective many of these medical issues become understandable and, indeed, novel methods of diagnosis and treatment can emerge. The proposed collaborative, a working group of paleoanthropologists, comparative anatomists, biomechanical engineers, and physicians will create new analytical approaches and new ways of viewing the disorders that uniquely plague our species. The results of this work include the development and implementation of a model curriculum, the creation of a website, and the publication of an edited volume. The disorders directly related to our way of walking include chronically sprained ankles, hernias, osteoporotic fractures of the hip, spine, and forearm, obstetric problems, knee problems, foot disorders, fatigue fractures, and many others. By understanding how our anatomy changed in order to walk upright, and why these changes occurred, we gain a better understanding of why these adaptations sometimes go awry resulting in disorders and pain.
Source: NESCent

August 10, 2014

22:00
Human cultural diversity is expressed in myriad ways (from social and marital norms to languages and religious practices), but what factors shape this diversity? Dating back to Darwin, multiple disciplines have debated the degree to which cultural diversity patterns are influenced by different factors, including history, demographics, and ecology. Over recent years an emerging set of studies have showcased how phylogenetic comparative methods from evolutionary biology can help resolve these long-held debates and revolutionize the field of cultural evolution. Now the major barrier to advances lies in the location of necessary data, which are spread across multiple disparate sources in linguistics, biogeography and anthropology. To overcome this challenge we will create D-PLACE (a Database of Phylogenies of Languages for the study of Cultural Evolution), a publicly available and expandable web-portal that will map over 100 cultural features onto language phylogenies and link these to ecological and environmental variables, empowering a whole new line of investigation into the drivers of cultural change and patterns of cultural diversity. We will produce a paper to introduce D-PLACE and outline the many types of questions in comparative anthropology the database can answer. Finally, we will demonstrate the power of this new resource by using D-PLACE to examine two long-standing and fundamental questions from comparative anthropology: (i) What drives the diversity of incest taboos (i.e. how human societies regulate who can mate and marry)? (ii) Can we characterize recurrent “human niches”, or are societies just arbitrary bundles of cultural features?
Source: NESCent

July 23, 2014

22:00
In the last two decades, models from evolutionary biology have made important contributions to demographic research on human fertility change. Within this evolutionary framework, two distinct traditions have focused on different processes of adaptation and time scales of change: (1) behavioral ecological perspectives have focused on how individual fertility decisions are shaped by local ecological circumstances, while (2) cultural evolutionary approaches have emphasized the role of socially transmitted information and changing social norms in shaping fertility behavior. While each tradition has made independent progress, research that integrates these approaches is necessary to improve our understanding of real fertility behavior, which results from a feedback between individual fertility decisions and social change. This approach requires combined attention to immediate ecological determinants of fertility decisions as well as the long-term processes that shape costs and benefits in a given environment. This workshop will bring together an international team of evolutionary behavioral scientists with complementary methodological and theoretical expertise in anthropology, psychology, and demography to develop (a) a synthetic article which proposes how these approaches can be integrated methodologically and theoretically, (b) an empirical article which applies our new synthetic framework to the study of fertility change in a particular fieldsite, demonstrating how the new methodological approach will work in practice and what we can learn through employing it, and (c) a multi-site grant proposal (UK, US, Bangladesh, Ethiopia, Bolivia, Poland) aimed at integrating and empirically testing these diverse evolutionary models of human fertility change.
Source: NESCent

July 22, 2014

22:30

I have written before about the expected genetic problems associated with inbreeding, including consanguinity and incest (relationships between people who are first cousins or closer). Conventionally, the evolutionary advantage of sexual over non-sexual reproduction is considered to be the creation of genetic diversity through heterozygosity. Inbreeding, by reducing heterozygosity, then seems to negate the advantages of sexual reproduction — it leads to the propagation of deleterious recessive alleles and thus inbreeding depression. So, there is a clear evolutionary dimension to the fact that incest avoidance is nearly universal in humans.

The best known exceptions to this situation are among royalty, including the family "trees" of the ancient Egyptian 18th Dynasty (see Tutankhamun and extreme consanguinity) and the Egyptian Ptolemaic dynasty (see Cleopatra, ambition and family networks), which were hybridization networks rather than conventional trees. The presence of consanguinity and incest among royal families then requires a biological explanation. As noted by van den Berghe & Mesher (1980):
Royal incest is best explained in terms of the general sociobiological paradigm of inclusive fitness ... Royal incest (mostly brother-sister; less commonly father-daughter) represents the logical extreme of hypergyny. Women in stratified societies maximize fitness by marrying up; the higher the status of a woman, the narrower her range of prospective husbands. This leads to a direct association between high status and inbreeding.The benefits of inclusive fitness refer to the increased number of offspring in future generations that result from increasing the reproductive success of close relatives. This is achieved via choice of mate. In other words, close relatives share genes, and the success of any relative in leaving offspring is a success for all relatives. Therefore, evolutionary fitness is a combination of individual fitness plus the fitness of close relatives. Inbreeding may reduce individual fitness but can increase inclusive fitness, as noted by Puurtinen (2011):
Theoretical work has shown that inclusive fitness benefits can favor close inbreeding even when this results in substantial reduction in offspring fitness. These models have identified the boundary level of inbreeding depression limiting the evolution of inbreeding among first-order relatives, that is, between full siblings, or between parents and offspring.So, there is a stable level of inbreeding in those populations that practice mate choice for optimal inbreeding. For example, the genetic risks of close inbreeding can be more than accounted for by the production of a highly related heir who has access to a wide choice of mates. Nevertheless:
For a wide range of realistic inbreeding depression strengths, mating with intermediately related individuals maximizes inclusive fitness.In other words, mating with very close relatives is unlikely to evolve via natural selection because it is not an optimal strategy; and we must thus look to a sociological component to incest (such as retaining wealth within the family), as well as a biological one.


In this context, it is interesting to note exceptions to the usual restriction of incest to the aristocracy. The society of Graeco-Roman Egypt (from c. 300 BCE to 300 CE) provides the best-documented case (eg. see Hopkins 1980; Shaw 1992; Parker 1996; Scheidel 1997; Huebner 2007; Remijsen & Clarysse 2008). [This era starts with the Ptolemaic dynasty, which marks the collapse of Egyptian rule of Egypt.] During this time a significant proportion of all marriages noted in official Roman census declarations were between full brothers and sisters. That is, the Roman-era Egyptians did not limit this type of inbreeding to any small group, but spread it across several social classes (mainly Greek settlers rather than native Egyptians).

As noted by Schiedel (1997):
According to official census returns from Roman Egypt (first to third centuries CE) preserved on papyrus, 23·5% of all documented marriages in the Arsinoites district in the Fayum (n=102) were between brothers and sisters. In the second century CE, the rates were 37% in the city of Arsinoe and 18·9% in the surrounding villages. Documented pedigrees suggest a minimum mean level of inbreeding equivalent to a coefficient of inbreeding of 0·0975 in second century CE Arsinoe. Undocumented sources of inbreeding and an estimate based on the frequency of close-kin unions indicate a mean coefficient of inbreeding of F=0·15-0·20 in Arsinoe and of F=0·10-0·15 in the villages at the end of the second century CE. These values are several times as high as any other documented levels of inbreeding.For comparison, the inbreeding F values for these family relationships are:
self
parent-offspring = siblings
uncle-niece = double first cousins
first cousins
first cousins once removed
second cousins 0.500
0.250
0.125
0.063
0.031
0.016
However, inbreeding depression seems not to have been a notable problem during this historical time. As noted by John Hawkes:
There is not a single mention in the evidence that links sibling marriage to negative genetic effects or unhappy marriages.This does not mean that there were no problems, but merely that any problems were not documented, as noted by Scheidel (1997):
Even in the absence of explicit references to inbreeding depression from Roman Egypt, there is no compelling reason to assume that brother–sister marriage could have remained entirely without negative consequences for the Arsinoites. It is however possible that, due to a low incidence of lethal recessives, such effects were considerably weaker than in some western samples. The census returns do not suggest lower levels of fertility or smaller numbers of children among sibling couples ...The practice seems to have stopped solely because it was contrary to Roman Law:
Before a.d. 212 the Romans had accepted discrepancies between their own legal practice and prevailing local customs and traditions in the Eastern provinces. Papyri from Roman Egypt, the Talmud, and the Romano-Syrian law book indeed reveal legal procedures which differed significantly from Roman law in matters such as marriage, guardianship, paternal authority, sales, and debts. The Constitutio Antoniana, however, made all free men and women of the Roman Empire into Roman citizens, and so Roman law became applicable to all inhabitants of Egypt. Brother-sister marriages cease to be documented in our Roman census returns from the early third century on. Our last [incest] testimony dates to a.d. 229.
References

Hopkins K (1980) Brother-sister marriage in Roman Egypt. Comparative Studies in Society and History 22: 303-354.

Huebner SR (2007) "Brother-sister" marriage in Roman Egypt: a curiosity of humankind or a widespread family strategy? Journal of Roman Studies 97: 21-49.

Parker S (1996) Full brother-sister marriage in Roman Egypt: Another look. Cultural Anthropology 11: 362-376.

Puurtinen M (2011) Mate choice for optimal (k)inbreeding. Evolution 65: 1501-1505.

Remijsen S, Clarysse W (2008) Incest or adoption? Brother-sister marriage in Roman Egypt revisited. Journal of Roman Studies 98: 53-61.

Scheidel W (1997) Brother-sister marriage in Roman Egypt. Journal of Biosocial Science 29: 361-371.

Shaw BD (1992) Explaining incest: brother-sister marriage in Graeco-Roman Egypt. Man 27: 267-299.

00:49

—_000_07050cdc982e49f1b9f56bfd926d0d2aBY2PR05MB792namprd05pro_ Content-Type: text/plain; charset=”us-ascii” Content-Transfer-Encoding: quoted-printable About 100 people generously volunteered to let their talks be recorded at the recent Evolution 2014 conference in Raleigh, NC, in June, and approximately 80 talks were successfully recorded (~10% of the total presented at the meeting). These were recorded via smartphones as part of an experimental program, so the quality is somewhat variable, but the majority are clear (i.e., slides easily readable). This effort was sponsored by the Society for the Study of Evolution and executed by a team of student volunteers. The list of recorded talks (with links to their abstracts and videos) is available at: http://bit.ly/1loRoew If you’d just like to browse the recorded talks, they are in a YouTube channel at: http://bit.ly/1rmlq8D Again, this was an experimental program, we appreciate the efforts of everyone who made these videos possible, and we apologize to the minority of speakers either who wanted but didn’t get their talks recorded or whose slides are not (easily) readable. We hope the community appreciates the accessibility these videos bring to exciting scientific results, and that these videos encourage people to attend one of the future Evolution conferences in person to see more great science and to interact in person. Next year’s conference will be in Guaruja, Brazil: http://bit.ly/1loRpyV (website in progress) —_000_07050cdc982e49f1b9f56bfd926d0d2aBY2PR05MB792namprd05pro_ Content-Type: text/html; charset=”us-ascii” Content-Transfer-Encoding: quoted-printable

Source: EVOLDIR