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At least 235 records · Page 13Linked to original sources
PubMed1993

Vitamin A2-based photopigments within the pineal gland of a fully terrestrial vertebrate.

Fully terrestrial vertebrates were previously thought to exclusively employ vitamin A1 to generate visual pigments. However, recent studies on the visual system of the lizard Anolis carolinensis have shown that its visual pigments are vitamin A2-based. This unexpected result prompted an investigation of the pineal photopigments in this species [13]. HPLC analysis has shown that this extraretinal photoreceptor also exclusively utilizes a vitamin A2-derived chromophore. The adaptive significance of this chromophore within the pineal is unclear. The extended long wavelength sensitivity characteristic of vitamin A2-based visual pigment systems may enhance important visual tasks such as prey detection or mate selection [13]. A similar argument cannot be made for the pineal, whose role is not image formation, but rather detection of the irradiance changes associated with dawn and dusk. We suggest that the pineal may passively utilize whatever retinoids have been adaptively selected by the visual system.

Adaptation, Physiological↗
PubMed1990

Is the 20th century increase in human height entirely nongenetic?

The twentieth-century increase in human height in affluent nations may not be entirely due only to such nurturant considerations as food supply and electric lights. A possible genetic role might be found in interactions of food supply, maternal pelvic size, and height-survival/vulnerability links, and in mate selection. Humans seem to be following the paleontological principle that most species tend to evolve larger sizes over time.

Biological Evolution↗
PubMed1990

Superoxide and hydrogen peroxide production by macrophages of New Zealand black mice.

Resident peritoneal macrophages from New Zealand Black (NZB) mice release O2- and H2O2 after adherence to a plastic surface without any chemical or particulate stimulant. This phenomenon is age dependent and more pronounced in animals with sever autoimmune disease. Significant differences were observed between the high and low breakage NZB sublines (HB and LB), which were previously developed by selective matings on the basis of chromosome breakage rates. The LB subline differs significantly from the HB subline with respect to autoimmune hemolytic anemia and tumor incidence. When the macrophages were stimulated with the tumor promoter TPA, the number of "responders" was higher in the HB than in the LB subline and correlated with the degree of splenomegaly, that is, with the severity of the disease. A negative response to agonist stimulation and very low spontaneous production of active oxygen species was observed in NZW and Swiss mice, which is the normal finding for resident macrophages according to data from the literature. The increased superoxide and hydrogen peroxide production by macrophages of NZB mice is discussed with respect to autoimmune disease and cancer.

Age Factors↗
PubMed2005

Appearance of symmetry, beauty, and health in human faces.

Symmetry is an important concept in biology, being related to mate selection strategies, health, and survival of species. In human faces, the relevance of left-right symmetry to attractiveness and health is not well understood. We compared the appearance of facial attractiveness, health, and symmetry in three separate experiments. Participants inspected front views of faces on the computer screen and judged them on a 5-point scale according to their attractiveness in Experiment 1, health in Experiment 2, and symmetry in Experiment 3. We found that symmetry and attractiveness were not strongly related in faces of women or men while health and symmetry were related. There was a significant difference between attractiveness and symmetry judgments but not between health and symmetry judgments. Moreover, there was a significant difference between attractiveness and health. Facial symmetry may be critical for the appearance of health but it does not seem to be critical for the appearance of attractiveness, not surprisingly perhaps because human faces together with the human brain have been shaped by adaptive evolution to be naturally asymmetrical.

Beauty↗
PubMed2006

Plumbing the sources of endogenous MHC class I peptide ligands.

From fish to fowl to pharaohs, nearly all cells in jawed vertebrates constitutively process and present peptides derived from endogenously synthesized polypeptides. Such peptides, snug in the binding groove of cell surface MHC class I molecules, enable CD8(+) T cell mediated immunosurveillance of viruses, other intracellular pathogens, and spontaneously arising tumors. The MHC class I system also plays an important role in olfactory-based vertebrate mate selection and perhaps even in preventing direct transmission of tumors between individuals. Recent findings indicate that MHC class I bound peptides are generated at higher efficiency from rapidly degraded polypeptides (including defective ribosomal products) than from old proteins. Intimately linking translation and antigen presentation makes perfect sense for immunosurveillance of acute virus infections, in which speed is of the essence to minimize viral replication, pathogenesis and transmission. The intriguing question of how translation is linked to presentation has prompted the immunoribosome hypothesis of immunosurveillance, which posits that MHC class I peptide ligands are preferentially generated from a subset of translation products.

Animals↗
PubMed2004

Ethnic differences in preferences for female weight and waist-to-hip ratio: a comparison of African-American and White American college and community samples.

This study examined both ethnic differences and differences between college and community samples in male preferences for ideal body size and shape in women. As expected, it was found that African-American men were more likely to choose heavier figures as ideal than White American men did. Contrary to expectations, there were no differences in chosen ideal weight between college and community subsamples. As expected, both ethnic groups chose figures with a low waist-to-hip ratio (WHR), but African-American men were more likely to choose a very low WHR as ideal. The findings replicate and extend research showing weight to be a more important cue than WHR in the mate-selection process and support the theory that African-American men's preferences may serve as a protective factor against eating and body image pathology in African-American women.

Adult↗
PubMed2006

New views of S-RNase-based self-incompatibility.

S-RNase-based self-incompatibility (SI) is the most widespread form of genetically controlled mate selection in plants. S-RNase controls pollination specificity in the pistil, while the newly discovered SLF/SFB controls pollination specificity in the pollen. A widely discussed model suggests that compatibility is explained by ubiquitylation and degradation of nonself-S-RNase and that, conversely, incompatibility is caused by failure to degrade self-S-RNase. This model is consistent with the long-standing view that S-RNase inhibition is central to SI. Recent results show, however, that S-RNase is compartmentalized in pollen tubes and, significantly, that compatibility might not require SLF/SFB. S-RNase compartmentalization and dislocation into the pollen tube cytoplasm might be similar to the trafficking of other cytotoxins such as ricin.

Plant Proteins↗
PubMed1999

Parasites and behavior: an ethopharmacological analysis and biomedical implications.

Parasites and disease are increasingly recognized as agents of behavioral, ecological and evolutionary importance having a variety of influences on their hosts other than the more obvious pathological and immunological changes. Parasites can have significant behavioral effects even when parasitism is sub-clinical with these effects proposed to either benefit the parasite (parasite 'manipulation'), benefit the host, or to simply arise as side-effects of the infection (parasitic 'constraints'). However, until relatively recently little attention has been paid to the neuromodulatory substrates that mediate these behavioral changes. Ethopharmacology incorporates an evolutionary approach to the study of behavior with pharmacological analysis of neuromodulatory mechanisms. As such, this approach is appropriate for, and has been applied to, the analysis of the effects of ectoparasites (e.g. biting and blood-feeding flies) and endoparasites (e.g. protozoa, nematodes) on a number of behaviors (e.g. pain inhibition, learning and memory, responses to predators and anxiety, mate selection) in selected host-parasite systems. Ethopharmacology suggests a promising direction by which neuromodulatory mechanisms that underlie the effects of parasites on behavior, including that of humans, can be addressed.

Animals↗
PubMed1998

Nuclear transfer in mammals: recent developments and future perspectives.

A clone can be defined as a set of genetically identical animals. Small clones of two or occasionally up to four identical animals can be obtained by embryo splitting or blastomere separation. Embryo cloning by nuclear transfer involves the transfer of genetic material from a donor cell (karyoplast) to the cytoplasm of an oocyte or zygote from which the genetic material has been removed (cytoplast). In farm animals, metaphase II oocytes are most widely used as cytoplasts. There are now many factors known to influence the efficiency of embryo cloning by nuclear transfer. These include stage of development and cell cycle of donor cells, the choice of the recipient cell, the methods for activation of oocytes, the cell cycle coordination between donor cell and recipient cytoplast, and the method for fusion between nuclear donor and recipient cytoplast. Recent progress in cloning embryos and animals from cultured cells of embryonic, fetal, or adult origin offers a wide spectrum of potential applications of nuclear transfer, such as the unlimited multiplication of elite embryos or animals from selected matings and the potential for precise genetic modification of farm animals for gene farming or xenotransplantation.

Animals↗
PubMedDate not supplied

Brain and face: communicating signals of health in the left and right sides of the face.

In human communication and mate selection the appearance of health sends signals regarding biological fitness. We compared the appearance of health in the sides of the face to previous results on left-right facial asymmetry in the appearance of beauty (1). The stimuli were created by aligning the left and right sides of the face each with its own mirror image. Here, participants viewed 38 pairs of left-left and right-right faces and judged which member of the pair looked healthier. No significant interaction emerged between decision (health vs attractiveness) and face side. Rather, in women's faces right-right was significantly more healthy and attractive than left-left, while in men's faces there was no significant left-right difference. In biology and evolution, health and beauty are closely linked and the findings here confirm this relationship in human faces.

Brain↗
PubMed1998

Evidence that both area V1 and extrastriate visual cortex contribute to symmetry perception.

Bilateral symmetry is common in nature and most animals seem able to perceive it. Many species use judgements of symmetry in various behaviours, including mate selection [1-3]. Originally, however, symmetry perception may have developed as a tool for generating object-centered, rather than viewer-centered, descriptions of objects, facilitating recognition irrespective of position or orientation [4]. There is evidence that the visual system treats the orientation of axes-of-symmetry in the same way it treats in orientation of luminance-defined contours [5], suggesting that axes-of-symmetry act as 'processing tokens' [6]. We have investigated the characteristics of neural mechanisms giving rise to the perceived orientation of axes-of-symmetry. We induced tilt aftereffects with symmetrical dot patterns, eliciting perceived angle expansion and contraction effects like those usually observed with luminance-defined contours [7,8]. Induction of aftereffects during binocular rivalry resulted in a reduction of the magnitude of these effects, consistent with the aftereffects being mediated in extrastriate visual cortex, probably between visual areas V2 and MT [9]. In a second experiment in which the aftereffects were induced monocularly, their magnitudes were measured in the unadapted eye. Contraction effects transferred completely, suggesting that they are mediated by binocular cells. Expansion effects did not transfer completely, consistent with their having a monocular component. These data suggest that information about the orientation of axes-of-symmetry may be available as early as area V1, but that processing continues in extrastriate cortex.

Humans↗
PubMed2001

Codon optimization markedly improves doxycycline regulated gene expression in the mouse heart.

Tetracycline regulated gene expression in transgenic animals is potentially a very powerful technique (Furth et al., 1994; Gossen & Bujard 1992). We have utilized this system in an attempt to overcome the perinatal lethality resulting from constitutive transgenic expression in the heart (Valencik & McDonald, Am J Physiol Heart Circ Physiol 280: H361-H367). We found that compound hemizygous animals created by mating selected reverse tetracycline transactivator (rtTA) and transresponder (TR) lines display tightly regulated TR expression in the heart. However, we identified two fundamental problems. First, codon usage bias appeared to severely limit the expression of the rtTA driven by the cardiac alpha-myosin heavy chain promoter. Second, co-injection of rtTA and TR transgenes led to compound hemizygous animals that exhibited unregulated TR gene expression. Codon optimization of the rtTA construct leads to marked improvement (increasing the average induction from 20-fold to 832-fold) in cardiac myocyte expression. The resulting opt-rtTA lines can be bred to homozygosity, facilitating rapid screening of F0 TR animals for doxycycline regulated transgene expression.

Animals↗
PubMed1990

Continuity and change: assortative marriage and the consistency of personality in adulthood.

How is personality stability possible amid the myriad of social changes and transformations that characterize a human life? We argue that by choosing situations that are compatible with their dispositions and by affiliating with similar others, individuals may set in motion processes of social interchange that sustain their dispositions across time and circumstance. To test this proposition we examined mate selection, using data on married couples from two ongoing longitudinal studies at the Institute of Human Development, University of California, Berkeley. Consistent with other research, the results point to homogamy as a basic norm in marriage. More important, the results show that marriage to a similar other promotes consistency in the intraindividual organization of personality attributes across middle adulthood. We offer some speculations for a more relational approach to the problem of individual continuity and change.

Adult↗
PubMed1993

Adaptive significance of female physical attractiveness: role of waist-to-hip ratio.

Evidence is presented showing that body fat distribution as measured by waist-to-hip ratio (WHR) is correlated with youthfulness, reproductive endocrinologic status, and long-term health risk in women. Three studies show that men judge women with low WHR as attractive. Study 1 documents that minor changes in WHRs of Miss America winners and Playboy playmates have occurred over the past 30-60 years. Study 2 shows that college-age men find female figures with low WHR more attractive, healthier, and of greater reproductive value than figures with a higher WHR. In Study 3, 25- to 85-year-old men were found to prefer female figures with lower WHR and assign them higher ratings of attractiveness and reproductive potential. It is suggested that WHR represents an important bodily feature associated with physical attractiveness as well as with health and reproductive potential. A hypothesis is proposed to explain how WHR influences female attractiveness and its role in mate selection.

Adipose Tissue↗
PubMed1995

Female judgment of male attractiveness and desirability for relationships: role of waist-to-hip ratio and financial status.

Two studies were conducted to examine the role of male body shape (as defined by waist-to-hip ratio [WHR]) in female mate choice. In Study 1, college-age women judged normal-weight male figures with WHR in the typical male range as most attractive, healthy, and possessing many positive personal qualities. In Study 2, 18-69-year-old women rated normal-weight male figures with differing WHRs and purported income for casual (having coffee) to most-committed (marriage) relationships. All women, regardless of their age, education level, or family income, rated figures with WHRs in the typical male range and higher financial status more favorably. These findings are explained within an evolutionary mate selection context.

Adolescent↗
PubMed1996

Spousal similarity in subjective well-being: the Cardiovascular Health Study.

This study examines the extent to which one spouse's subjective well-being predicts that of the partner (N = 1,040 spousal pairs, 65 years or older). Prior research is extended in two ways: (a) The similarity of both affective domains (depressive symptoms, feelings about life as a whole, and satisfaction with the meaning and purpose of life) and nonaffective domains (perceived health) are examined, and (b) known predictors of well-being in older adults (sociodemographic variables, self and spouse health status variables, and exposure to common environmental events) are statistically controlled. Results indicate that one spouse's assessments of well-being and depression predict the other's well-being even after controlling for known predictors of these outcomes. Given the similarity of findings for affective and nonaffective domains, multiple mechanisms, including contagion, mate selection, and common environmental influences, are speculated as likely to contribute to this phenomenon.

Activities of Daily Living↗
PubMed1980

Data from kinships of monozygotic twins indicate maternal effects on verbal intelligence.

Familial resemblance in intellectual skills is well documented, but its interpretation is a source of continuing controversy. The critical problem is that a family's shared genes are confounded with its shared experiences, and controls possible in animal research (selective mating, cross-fostering, and uniform or randomised environments) do not directly apply to human subjects. Conventional twin and family methods reveal substantial genetic variance in intelligence quotient (IQ) test scores, but the same methods also document significant environmental influences. Research designs which can identify the nature of these environmental factors may effect progress in the 'IQ debate' (ref. 1). The families of monozygotic (MZ) twins provide a new research design which permits a unique assessment of maternal influences in quantitative traits. We describe here initial applications of the design to verbal IQ, with results suggesting that maternal effects significantly contribute to familial similarity in verbal intelligence.

Adolescent↗
PubMed1980

Kin preference in infant Macaca nemestrina.

The ability to recoginize conspecifics is a prerequisite for many types of social behaviour, including, for example, parent-offspring relation, mate selection and recognition, territorial defence and dominance coalitions. This ability is of special importance to Hamilton's kin selection hypothesis, which predicts that an individual's behaviour towards a conspecific will depend on the degree of genetic relatedness between them. Although recognition depends on previous experience between individuals in some species, this does not precluded the possibility that recognition could occur in its absence. For example, juveniles who disperse before nonlittermate siblings are born or adult males who do not participate in rearing their young might benefit from recognition abilities that are independent of prior association between the individuals. Here we show that young pigtail macaques prefer to interact with a related over an unrelated monkey in a laboratory test. Because subjects were separated from their dams at birth and reared apart from all other relatives, results suggest that kin recognition can occur in the absence of prior association with relatives.

Age Factors↗