Interesting Topics on Evolution

...is to find a partner who will shelter and provide so's the progeny can be successful.

Rate of molecular evolution of the seminal protein gene SEMG2 correlates with levels of female promiscuity

Postcopulatory sperm competition is a key aspect of sexual selection and is believed to drive the rapid evolution of both reproductive physiology and reproduction-related genes. It is well-established that mating behavior determines the intensity of sperm competition, with polyandry (i.e., female promiscuity) leading to fiercer sperm competition than monandry. Studies in mammals, particularly primates, showed that, owing to greater sperm competition, polyandrous taxa generally have physiological traits that make them better adapted for fertilization than monandrous species, including bigger testes, larger seminal vesicles, higher sperm counts, richer mitochondrial loading in sperm and more prominent semen coagulation. Here, we show that the degree of polyandry can also impact the dynamics of molecular evolution. Specifically, we show that the evolution of SEMG2, the gene encoding semenogelin II, a main structural component of semen coagulum, is accelerated in polyandrous primates relative to monandrous primates. Our study showcases the intimate relationship between sexual selection and the molecular evolution of reproductive genes.

TB: i think healyje's citation could bear a bit of analysis. female promiscuity would be off the chart at a hollywood party attended by an important producer, but nonexistent in certain remote mormon communities. of course, interpretation of raw data in the latter venue could easily be influenced by researcher bias.

A developmental dynamics perspective allows researchers to abandon popular yet misleading metaphorical references to gene
action (e.g., genes as the storehouse of information or programs for development, genes as the overseers or regulators of development) in favor of characterizing gene activity as a molecular, intracellular event (Johnston & Edwards, 2002). Such an approach emphasizes the unpacking of the mechanics of developmental processes and would include (as first steps) coordinated interdisciplinary efforts to (a) systematically identify individual DNA sequences and their associated products, (b) determine the nongenetic factors involved in constructing and regulating the structure and function of the these products, (c) trace these products and their influence across the various levels of organization that make up the individual organism, and (d) determine how previous developmental outcomes and current experiences influence these processes in ecologically meaningful contexts (see Wagner, Chiu, & Laubichler, 2000, for a similar evo-devo view). The psychological sciences have much to offer in this effort, particularly to explain how previous developmental outcomes and current experiences influence these biological processes in specific contexts.

Viewing genes as reciprocal partners in the developmental processes underlying phenotypic traits and characters requires a shift
in the way the “environment” is typically characterized in discussions of both development and evolution. From a developmental
dynamics framework, the environment cannot be reduced to “supportive conditions” or to an abstract “poser of problems” that must be solved—both common perspectives within contemporary evolutionary psychology. Rather, the specific physical, biological, and social environments within which the individual organism develops are recognized to be inseparable parts of the developmental system. Hence, the organism and its environment are best characterized as codefining (Turvey & Shaw, 1995), and evolution can be seen to result from a dialectical interaction between organisms and environments through ontogeny (Levins & Lewontin, 1985). Attempts to rigidly dichotomize the contributions of the organism and its environment to development or evolution typically lead to the need to invoke other troubling and unnecessary dichotomies, including the nondevelopmental phylogenetic–ontogenetic causal framework reviewed in previous sections and widely embraced by evolutionary psychologists. Whereas such dichotomies have allowed evolutionary psychologists to virtually ignore developmental dynamics in their accounts of human development and behavior (by arguing that they are interested in phylogenetic rather than ontogenetic questions), we argue that evolutionary and developmental frameworks do not provide fundamentally different ways of explaining behavior. Rather, developmental processes are fundamental both to individual development and to evolutionary change.

Instead of asking reductionistic questions about the genetic basis of human development and behavior, a developmental dynamics
approach is interested in what are the contributions of the various components and levels of the organism–environment system and their interactions to phenotypic outcome. This empirically based unpacking of the mechanics of developmental processes requires going beyond the notion of the causal powers of the gene and focusing on the broader relational principles that govern and constrain development and evolution.

the evolutionary psychologists have come up with a great explanation for the battle of the sexes. men and women have differing interests, due to the very nature of gender, for forwarding their personal genes into spacetime. because men can potentially have an almost unlimited number of offspring, they tend to be promiscuous. women, on the other hand, produce one sex cell per month. if they become impregnated, it'll take nine months to produce a child, followed by weaning. most women don't want to bang 'em out once a year, in spite of the papal imperative. so more is not better for a woman. they tend to be choosy. their best strategy for long-term gene forwarding is to find a quality partner who will shelter and provide so's the progeny can be successful.

due to the very nature of gender, for forwarding their personal genes into spacetime.

their best strategy for long-term gene forwarding is to find a quality partner who will shelter and provide so's the progeny can be successful.

Like Mayr, most evolutionary psychologists argue for the heuristic value of the conceptual decoupling of proximate (ontogenetic)
and evolutionary (phylogenetic) levels of explanation (see Buss, 1999; Crawford, 1998; Daly & Wilson, 1978; Gaulin &
McBurney, 2002). Furthermore, most assume that evolutionary factors are somehow ontologically prior to and more fundamental
than proximate factors in directing phenotypic outcomes. This viewpoint is evident in nearly all current evolutionary accounts of
human behavior and development (but see Bjorklund & Pellegrini, 2002, for a well-developed exception). Lickliter and Berry (1990) termed this dichotomous conceptual framework the phylogeny fallacy. The phylogeny fallacy is based on the assumptions (a) that phylogeny and ontogeny are alternative processes by which information is made available to the developing individual and (b) that specification for an organism’s phenotype can exist independently and in advance of its real-time developmental processes (see also Ingold, 2001; Oyama, 1985). This framework is based (often implicitly) on a strong form of genetic predeterminism and ignores or downplays the fundamental role of developmental processes in the realization of all phenotypic characters or traits.

Assertions of polyandry have nothing to do with sociology or psychology, but rather everything to the evolution of the human male and [particularly] female reproduction system relative to sperm competition.

Jan: Or perhaps biology uses the terms differently than anthropologists do?

there is considerable evidence of efficacy for several mind-body therapies in the treatment of coronary artery disease (eg, cardiac rehabilitation), headaches, insomnia, incontinence, chronic low back pain, disease and treatment-related symptoms of cancer, and improving postsurgical outcomes.

We propose that clinical symptoms may be modified by mind-body therapies through several interrelated mechanisms, including: (a) activation of specific EHN structures, resulting in functional cortical (and subcortical) reorganization and improved interhemispheric balance; (b) more efficient cortical modulation of limbic and brainstem homeostatic centers and enhanced peripheral-central integration of information, expressed at the periphery as a change in autonomic (sympathovagal) balance and immune (pro-inflammatory cytokine profile) function; (c) re-patterning of primary interoceptive and higher-order homeostatic representations, resulting in more adaptive long-term psychophysiological responses as well as reduced expression of adverse symptoms; and (d) modulation of the epigenetic regulators (e.g., growth factors, hormones, histone function, DNA methylation) that can mediate cellular responses to environmental stress. In this way, mind-body therapies ameliorate symptoms via influence at multiple levels, from gene expression (cellular level) to the interaction of cortical brain regions that mediate systemic responses to internal and external challenges, including stress.

Currently, behavioral development is thought to result from the interplay among genetic inheritance, congenital
characteristics, cultural contexts, and parental practices as they directly impact the individual. Evolutionary ecology points to another contributor, epigenetic inheritance, the transmission to offspring of parental phenotypic responses to environmental challenges—even when the young do not experience the challenges themselves. Genetic inheritance is not altered, gene expression is. Organismic pathways for such transmission
exist. Maternal stress during the latter half of a daughter’s gestation may affect not only the daughter’s but also grand-offspring’s physical growth. The author argues that temperamental variation may be influenced in the same way. Implications for theory and research design are presented along with testable predictions.