Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

Leu-M

How the mind works

In men, high levels of endogenous testosterone (T) seem to encourage behavior intended to dominate - to enhance one's status over - other people. Sometimes dominant behavior is aggressive, its apparent intent being to inflict harm on another person, but often dominance is expressed nonaggressively. Sometimes dominant behavior takes the form of antisocial behavior, including rebellion against authority and law breaking. Measurement of T at a single point in time, presumably indicative of a man's basal T level, predicts many of these dominant or antisocial behaviors. T not only affects behavior but also responds to it. The act of competing for dominant status affects male T levels in two ways. First, T rises in the face of a challenge, as if it were an anticipatory response to impending competition. Second, after the competition, T rises in winners and declines in losers. Thus, there is a reciprocity between T and dominance behavior, each affecting the other. We contrast a reciprocal model, in which T level is variable, acting as both a cause and effect of behavior, with a basal model, in which T level is assumed to be a persistent trait that influences behavior. An unusual data set on Air Force veterans, in which data were collected four times over a decade, enables us to compare the basal and reciprocal models as explanations for the relationship between T and divorce. We discuss sociological implications of these models.

https://users.ox.ac.uk/~kgroup/publications/pdf/kacelnik_norris_1998_bbs_testosterone.pdf

Testosterone and dominance in men.

The excitement and controversy surrounding the potential role of human embryonic stem (ES) cells in transplantation therapy have often overshadowed their potentially more important use as a basic research tool for understanding the development and function of human tissues. Human ES cells can proliferate without a known limit and can form advanced derivatives of all three embryonic germ layers. What is less widely appreciated is that human ES cells can also form the extra-embryonic tissues that differentiate from the embryo before gastrulation. The use of human ES cells to derive early human trophoblast is particularly valuable, because it is difficult to obtain from other sources and is significantly different from mouse trophoblast. Here we show that bone morphogenetic protein 4 (BMP4), a member of the transforming growth factor-beta (TGF-beta) superfamily, induces the differentiation of human ES cells to trophoblast. DNA microarray, RT-PCR, and immunoassay analyses demonstrate that the differentiated cells express a range of trophoblast markers and secrete placental hormones. When plated at low density, the BMP4-treated cells form syncytia that express chorionic gonadotrophin (CG). These results underscore fundamental differences between human and mouse ES cells, which differentiate poorly, if at all, to trophoblast. Human ES cells thus provide a tool for studying the differentiation and function of early human trophoblast and could provide a new understanding of some of the earliest differentiation events of human postimplantation development.

BMP4 initiates human embryonic stem cell differentiation to trophoblast.

List of contributors Preface 1 The study of mammalian cooperative breeding Nancy G Solomon and Jeffrey A French 2 The bioenergetics of parental behaviour and the evolution of alloparental care in marmosets and tamarins Suzette D Tardif 3 Proximate regulation of singular breeding in Callitrichid primates Jeffrey A French 4 Cooperative breeding, reproductive suppression and body size in canids Patricia D Moehlman and Heribert Hofer 5 Hormonal and experiential factors in the expression of social and parental behaviour in canids Cheryl S Asa 6 Variation in reproductive suppression among dwarf mongooses: interplay between mechanisms and evolution Scott R Creel and Peter M Waser 7 Dynamic optimization and cooperative breeding: an evaluation of future fitness effects Jeffrey R Lucas, Scott R Creel and Peter M Waser 8 Examination of alternative hypotheses for cooperative breeding in rodents Nancy G Solomon and Lowell L Getz 9 The psychobiological basis of cooperative breeding in rodents C Sue Carter and R Lucille Roberts 10 Cooperative breeding in naked mole-rats: implications for vertebrate and invertebrate sociality Eileen A Lacey and Paul W Sherman 11 The physiology of a reproductive dictatorship: regulation of male and female reproduction by a single breeding female in colonies of naked mole-rats Christopher G Faulkes and David H Abbott 12 Factors influencing the occurrence of communal care in plural breeding mammals Susan E Lewis and Anne E Pusey 13 A bird's-eye view of mammalian cooperative breeding Ronald L Mumme Index

Cooperative Breeding in Mammals

https://www.unomaha.edu/college-of-arts-and-sciences/callitrichid/publications/2010/2010_02.pdf

Manipulation of the oxytocin system alters social behavior and attraction in pair-bonding primates, Callithrix penicillata

Within any hierarchical society, an individual's social rank can have profound effects on its health and reproductive success, and rank-related variation in these traits is often mediated by variation in endocrine function. Maternal effects mediated by prenatal hormone exposure are potentially important for non-genetic inheritance of phenotypic traits related to social rank, and thus for shaping individual variation in behaviour and social structure. Here we show that androgen concentrations in wild female spotted hyaenas (Crocuta crocuta) are higher during late gestation in dominant females than in subordinate females. Furthermore, both male and female cubs born to mothers with high concentrations of androgens in late pregnancy exhibit higher rates of aggression and mounting behaviour than cubs born to mothers with lower androgen concentrations. Both behaviours are strongly affected in other mammals by organizational effects of androgens, and both have important effects on fitness in hyaenas. Therefore, our results suggest that rank-related maternal effects of prenatal androgen exposure can adaptively influence offspring phenotype in mammals, as has previously been shown to occur in birds. They also suggest an organizational mechanism for the development of female dominance and aggressiveness in spotted hyaenas, traits that may offset the costs of extreme virilization.

Rank-related maternal effects of androgens on behaviour in wild spotted hyaenas.

Interactions among Paternal Behavior, Steroid Hormones, and Parental Experience in Male Marmosets (Callithrix kuhlii)

The influence of various social environments on estrogen excretion, scent marking, and the expression of sociosexual behavior was examined in cotton-top tamarins (Sanguinus o oedipus) Behavioral observations and urine collections were conducted on five females while first housed in their natal family group or in the presence of another cycling adult female and then while housed with an unrelated adult male in a separate cage Behavioral observations only were conducted on males in natal family groups and while housed with an unrelated adult female Levels of urinary estrone and estradiol for females were measured by specific radioimmunoassays Females housed in family groups or in the presence of an adult cycling female showed low and noncyclic patterns of estrogen excretion Removal from these environments resulted in a rapid increase in urinary estrone and estradiol and three of five females demonstrated cyclic patterns of estrone excretion Rates of anogenital marking in females were elevated after the social change, and sexual interactions, virtually absent in the original environments, were observed in all five females In males, similar manipulations of the social environment affected the expression of sexual behavior, but not scent marking The social environment, therefore has a profound impact on fertility and sociosexual behavior in cotton-top tamarin groups, with implications for callitrichid social structure and behavior

Jeffrey A. French

Papers

Cooperative Breeding in Mammals

Manipulation of the oxytocin system alters social behavior and attraction in pair-bonding primates, Callithrix penicillata

Rank-related maternal effects of androgens on behaviour in wild spotted hyaenas.

Interactions among Paternal Behavior, Steroid Hormones, and Parental Experience in Male Marmosets (Callithrix kuhlii)

The effect of social environment on estrogen excretion, scent marking, and sociosexual behavior in tamarins (Saguinus oedipus).