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Females should be choosier than males about prospective mates because of the high costs of inappropriate mating decisions. Both theoretical and empirical studies have identified factors likely to influence female mate choices. However, male-male social interactions also can affect mating decisions, because information about a potential mate can trigger changes in female reproductive physiology. We asked how social information about a preferred male influenced neural activity in females, using immediate early gene (IEG) expression as a proxy for brain activity. A gravid female cichlid fish (Astatotilapia burtoni) chose between two socially equivalent males and then saw fights between these two males in which her preferred male either won of lost. We measured IEG expression levels in several brain nuclei including those in the vertebrate social behavior network (SBN), a collection of brain nuclei known to be important in social behavior. When the female saw her preferred male win a fight, SBN nuclei associated with reproduction were activated, but when she saw her preferred male lose a fight, the lateral septum, a nucleus associated with anxiety, was activated instead. Thus social information alone, independent of actual social interactions, activates specific brain regions that differ significantly depending on what the female sees. In female brains, reproductive centers are activated when she chooses a winner, and anxiety-like response centers are activated when she chooses a loser. These experiments assessing the role of mate-choice information on the brain using a paradigm of successive presentations of mate information suggest ways to understand the consequences of social information on animals using IEG expression. cellular homologue of fos | early growth response factor 1 | preoptic area | egr-1 doi/ 10.1073/pnas.1010442107

A significant genetic effect was found that influence variation in both measurement of mate preference towards altruistic traits and the preferred trait. The findings support the relationship between sexual selection and human altruism towards non-kin.

Coordination of animal behavior with reproductive status is often achieved through elaboration of hormones by the gonad. In the nematode Caenorhabditis elegans, adult males explore their environment to locate mates. Mate searching is regulated by presence of mates, nutritional status, and a signal from the gonad. Here we show that the gonadal signal acts via the nuclear receptor DAF-12, a protein known to regulate several C. elegans life-history traits. DAF-12 has both activational and organizational functions to stimulate exploratory behavior and acts downstream of the gonadal signal, outside of the gonad. DAF-12 acts upstream of sensory input from mating partners and physiological signals indicating nutritional status. Mate searching was rescued in germ-line ablated animals, but not if both germ line and somatic gonad were ablated, by a precursor of the DAF-12 ligand, dafachronic acid (DA). The results are interpreted to suggest that the germ line produces a DA precursor that is converted to DA outside of the germ line, possibly in the somatic gonad. As it does in other pathways in which it functions, in regulation of male mate searching behavior DAF-12 acts at a choice point between alternatives favoring reproduction (mate searching) vs. survival (remaining on food).

The Evenks and Evens, who speak closely related languages belonging to the Northern Tungusic branch of the Tungusic family, are nomadic reindeer herders and hunters. They are spread over an immense territory in northeastern Siberia, and consequently different subgroups are in contact with diverse peoples speaking Samoyedic, Turkic, Mongolic, Chukotka-Kamchatkan, and Yukaghir languages. Nevertheless, the languages and culture of the Evenks and Evens are similar enough for them to have been classified as a single ethnic group in the past. This linguistic and cultural similarity indicates that they may have spread over their current area of habitation relatively recently, and thus may be closely related genetically. On the other hand, the great distances that separate individual groups of Evens and Evenks from each other might have led to preferential mating with geographic neigh bors rather than with linguistically related peoples. In this study, we assess the correlation between linguistic and genetic relationship in three different subgroups of Evenks and Evens, respectively, via mtDNA and Y-chromosomal analyses. The results show that there is some evidence of a common origin based on shared mtDNA lineages and relatively similar Y-haplogroup frequencies amongst most of the Evenk and Even subgroups. However, there is little sharing of Y-chromosomal STR haplotypes, indicating that males within Evenk and Even subgroups have remained relatively isolated. There is further evidence of some female admixture in different Even subgroups with their respective geographic neighbors. However, the Tungusic groups, and especially the Evenks, show signs of genetic drift, making inferences about their prehistory difficult. KEY WORDS human populations; Evenks; Evens; molecular anthropology

Environmental contamination by endocrine-disrupting chemicals (EDC) can have epigenetic effects (by DNA methylation) on the germ line and promote disease across subsequent generations. In natural populations, both sexes may encounter affected as well as unaffected individuals during the breeding season, and any diminution in attractiveness could compromise reproductive success. Here we examine mate preference in male and female rats whose progenitors had been treated with the antiandrogenic fungicide vinclozolin. This effect is sex-specific, and we demonstrate that females three generations removed from the exposure discriminate and prefer males who do not have a history of exposure, whereas similarly epigenetically imprinted males do not exhibit such a preference. The observations suggest that the consequences of EDCs are not just transgenerational but can be 'transpopulational', because in many mammalian species, males are the dispersing sex. This result indicates that epigenetic transgenerational inheritance of EDC action represents an unappreciated force in sexual selection. Our observations provide direct experimental evidence for a role of epigenetics as a determinant factor in evolution. endocrine disruption | vinclozolin | sexual selection | odor salience

A series of population genetic models were created to study the evolutionary equilibria and dynamics resulting from male mate choice during polygyny, alone and in the context of mutual mate choice by both sexes. Results reveal that if male and female preferences and traits are all controlled by different loci then the male and female mate choice systems are decoupled.

The contribution of studies on the major histocompatibility complex (MHC) in non-model species is reviewed to understand the effect of ecological and ethological processes on the tempo and mode of evolution at the MHC. It is indicated that positive selection operates on MHC loci to maintain MHC variation.

The incidence of albinism in Hopi Indians has been estimated as approximately 1 in 200 individuals. It has been suggested that 'cultural' selection as the result of a mating advantage of males with albinism has been important in the maintenance of this high incidence. To examine this hypothesis quantitatively, a model that includes male-mating advantage, mutation, and viability selection is analyzed. In order to play an important role in the maintenance of the high incidence of albinism, the necessary mating advantage of males with albinism appears unrealistically high. However, if the extent of viability selection against individuals with albinism is not as large as previously assumed, the necessary amount of mating advantage is not as high. Other related aspects are also discussed here, such as the type of albinism in Hopi Indians and its impact, the conditions for a polymorphism with male-mating advantage and viability selection, and the time necessary to change the incidence of albinism either by the relaxation or institution of male-mating advantage. KEY WORDS gene flow; male-mating advantage; mutation; polymorphism; selection

We use a general additive quantitative genetic model to study the evolution of costly female mate choice by the 'handicap' principle. Two necessary conditions must be satisfied for costly preference to evolve. The conditions are (i) biased mutation pressure on viability and (ii) a direct relationship between the degree of expression of the male mating character and viability. These two conditions explain the success and failure of previous models of the 'handicap' principle. Our model also applies to other sources of fitness variation like migration and host-parasite coevolution, which cause effects equivalent to biased mutation.

Fisher's runaway process is the standard explanation of the evolution of exaggerated female preferences. But mathematical formulations of Fisher's process (haploid and additive diploid) show if cannot cause stable exaggeration if female preference carries a cost. At equilibrium female fitness must be maximized. Our analysis shows that evolutionary stable exaggeration of female preference can be achieved if mutation pressure on the male character is biased, that is, mutation has a directional effect. At this equilibrium female fitness is not maximized. We discuss the reasons and evidence for believing that mutation pressure is typically biased. Our analysis highlights the previously unacknowledged importance of biased mutation for sexual selection.

This study examined the genetic and environmental contribution to people's preference for spouses and friends to be similar to themselves. In their responses to 130 personality, attitude, and demographic questions, 174 pairs of monozygotic (MZ) twins resembled each other (r= .53) more than did 148 pairs of dizygotic (DZ) twins (r= .32), 322 pairs of spouses (r= .32), and 563 pairs of best friends (r= .20). It was not previously recognized that spouses and friends are as similar as DZ twins. MZ twins also chose spouses and best friends more similar to their co-twins' friends and spouses than did DZ twins (mean rs = .22 vs. .14). The twins' preference for spouses and friends similar to themselves was about 34% due to the twins' genes, 12% due to the twins' common environment, and 54% due to the twins' unique (nonshared) environment. Similarity to partners was more pronounced on the more heritable items than the less heritable items. It is concluded that people are genetically inclined to choose as social partners those who resemble themselves at a genetic level.

High mating effort and antisocial and delinquent behaviors are closely linked. Some delinquent behaviors may honestly signal genetic quality. Men who exhibit high mating effort and who have high genetic quality would be expected to engage in more sexual coercion than other men because its costs to them are lowered by female preferences for them as sexual partners.

Preference for partners with low fluctuating asymmetry (FA) may produce 'good gene' benefits. However, Gangestad & Simpson's analysis does not exclude immediate benefits of fertility. Low FA is related to fertility in men and women. Short-term changes in FA are correlated with fertility in women. It is not known whether temporal fluctuations in the FA of men are related to short-term fertility status.

Prior to agriculture, human societies were small, with little variation for good genes sexual selection (GGSS) to work on. Across cultures, variation in paternal care makes the benefits of GGSS highly variable. Despite these caveats, female preferences for traits like male body symmetry suggest one reason for female short-term mating is gene shopping.

Proxies of mate value must be evolutionarily salient. Gangestad & Simpson (G&S) have made a good case that fluctuating asymmetry is an important proxy of male mate value that correlates well with genetic and developmental quality. The use of financial variables as proxies for male investment ability by Gangestad, Simpson, and virtually every other investigator of human mating in evolutionary perspective, is, however, more problematic.

Genes controlling the choice of sexual strategy must be sensitive to critical environmental contingencies, including the presence of other strategically relevant genetic traits. To determine which strategy works best for each individual, one must assess both its environment and itself within that environment. Psychosexual development involves an assessment of sociosexual affordances, strategically calibrating optimal utilization of physical and psychosocial assets.

An alternative interpretation of Gangestad & Simpson's findings features the assumption that only a subgroup of those men who are low in fluctuating asymmetry are typically available for short-term mating. In general, these philandering men do not offer higher genetic quality than men who are securely attached to long-term mates.

Gangestad & Simpson's account of the role of good-gene sexual selection in conditional human mating strategies is reasonably convincing, but could be more so with a little more attention to (1), dropping unnecessary sub hypotheses and especially (2) the inclusion of alternative evolutionary explanations.

Social roles theorists claim that differences between the sexes are of limited consequence. Such misperceptions lead to misunderstanding the important role of sexual selection in explaining phenotypic differences both between species and within humans. Countering these claims, we explain how sexual dimorphism in humans affect expressions of artistic display and patterns of male and female aggression across the ovulatory cycle. doi: 10.1017/S0140525X09990240

A number of studies suggest that women find artistically creative men attractive, especially in the short-term mating context. Artistic creativity (but not mathematical or technical creativity) is linked to psychosis-proneness. I hypothesise that in preferring artistically creative men, women may be choosing paternal genotypes that make babies that are not excessively somatically demanding on them.

Potential mates analysis is used to determine some of the social and demographic characteristics that influence mate choice in a small island population. Potential mate pools are defined for males in this population; characteristics such as population size and composition with respect to consanguinity are specified. Determinants of mate choice are examined in light of mate availability and potential mate pool characteristics for endogamous matters, exogamous maters, nonmaters, and males of various occupations. Random kinship is assessed from potential mate pools and compared to kinship between actual mates. The island community approximated a random mating population from 1700 to 1900 with some evidence for consanguinity avoidance intensifying in the period 1900-1950. Despite the island's small population size, kinship coefficients between random mates and actual mates are not high because of relatively high immigration rates. Having considered the contributions of various factors that influence mate choice, the significance of the island mating structure for genetic variation and the distributions of certain genetic disorders is discussed.

A study of the genetic similarity theory as it pertains to human assortative mating reveals that it is possible to formulate theories that make the same predictions. Positive assortative mating has not yet been conclusively proved for people having the same blood groups. People choose spouses who resemble them solely because of similarity of environment.