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How flies get their size: genetics meets physiology.

Body size affects important fitness variables such as mate selection, predation and tolerance to heat, cold and starvation. It is therefore subject to intense evolutionary selection. Recent genetic and physiological studies in insects are providing predictions as to which gene systems are likely to be targeted in selecting for changes in body size. These studies highlight genes and pathways that also control size in mammals: insects use insulin-like growth factor (IGF) and Target of rapamycin (TOR) kinase signalling to coordinate nutrition with cell growth, and steroid and neuropeptide hormones to terminate feeding after a genetically encoded target weight is achieved. However, we still understand little about how size is actually sensed, or how organ-intrinsic size controls interface with whole-body physiology.

Animals↗

The beneficial effects of body fat and adipose tissue in humans.

Body fat and adipose tissue are considered to have beneficial effects when they promote or protect the present and future function. These effects do not occur at absolute amounts or percentages of the body weight but rather they are context specific. Body fat stores are the major energy stores of the body and are important determinants of survival in starvation or undernutrition. Reproduction features highly as a biological function. Humans are alone in having major sex-specific fat stores and patterns of fat distribution and these have been linked with the onset and maintenance of menstruation, with mate selection and sexual signalling, and with favourable pregnancy and lactation outcomes. To survive and reproduce good physical and psychological health are advantageous attributes. Work metabolism, bone health and, possibly immune function and energy balance itself, are related in functionally beneficial ways to fat content and distribution.

Adipose Tissue↗

The molecular basis for UV vision in birds: spectral characteristics, cDNA sequence and retinal localization of the UV-sensitive visual pigment of the budgerigar (Melopsittacus undulatus).

Microspectrophotometric (msp) studies have shown that the colour-vision system of many bird species is based on four pigments with absorption peaks in the red, green, blue and UV regions of the spectrum. The existence of a fourth pigment (UV) is the major difference between the trichromacy of humans and the tetrachromacy of such birds, and recent studies have shown that it may play a determining role in such diverse aspects of behaviour as mate selection and detection of food. Avian visual pigments are composed of an opsin protein covalently bound via a Schiff-base linkage to the chromophore 11-cis-retinal. Here we report the cDNA sequence of a UV opsin isolated from an avian species, Melopsittacus undulatus (budgerigar or small parakeet). This sequence has been expressed using the recombinant baculovirus system; the pigment generated from the expressed protein on addition of 11-cis-retinal yielded an absorption spectrum typical of a UV photopigment, with lambdamax 365+/-3 nm. This is the first UV opsin from an avian species to be sequenced and expressed in a heterologous system. In situ hybridization of this sequence to budgerigar retinas selectively labelled a sub-set of UV cones, representing approx. 9% of the total cone population, that are distributed in a semi-regular pattern across the entire retina.

Amino Acid Sequence↗

Biochemical and morphological characterization of spontaneously hypertensive hyperlipidaemic rats.

1. To develop and characterize a new animal model of hypertension and hyperlipidaemia, we cross-bred spontaneously hypertensive rats (SHR) with spontaneously hyperlipidaemic rats (HLR). 2. A new strain of spontaneously hypertensive hyperlipidaemic rats (SHHR) was established at generation 10 through selective mating of brothers and sisters (systolic blood pressure > 150 mmHg, plasma cholesterol > 150 mg/dL). Cross-bred Wistar-Kyoto (WKY) rats and Sprague-Dawley (SD) rats (SDWKY rats) were used as a control. 3. Adrenaline and noradrenaline levels in the plasma and adrenal medulla of male SHHR were significantly higher than those of male SDWKY rats. The tyrosine hydroxylase activity in the adrenal medulla of male SHHR was significantly higher than that of male SDWKY rats. Low-density lipoprotein expression was found in the plasma of male and female SHHR and HLR. Cholesterol 7alpha-hydroxylase mRNA expression in the liver of male SHHR was lower than that of male SDWKY rats. Endothelium lesions and lipid deposition under the endothelium were observed in the aorta of 24-month-old SHHR, especially female SHHR, but not in age-matched HLR and SDWKY rats. 4. The hypertension of this new animal model of hypertension and hyperlipidaemia may be related to increased catecholamine activity and the hyperlipidaemia may be related to changes in the expression of cholesterol 7alpha-hydroxylase mRNA and lipoprotein profiles. The SHHR may be valuable in the study of mechanisms of atherosclerosis and the evaluation of anti-atherosclerosis drugs as a new strain of cardiovascular disease.

Animals↗

Child maltreatment 2002: recognition, reporting and risk.

BACKGROUND: Child abuse is a major cause of morbidity and mortality in the USA and in all other countries which have studied its incidence. It is the second leading cause of death of children in the USA. To decrease the incidence of child abuse and improve the welfare of children there must be international efforts to recognize, and report child abuse and to decrease those risk factors, which place children in jeopardy. In the USA, reports of child maltreatment have decreased each year since 1994 after nearly two decades of increase. The increase was associated with the passage of laws that mandated reporting child maltreatment and increased recognition of maltreatment. RESULTS: Several theories have been proposed to explain the decrease. These include: improved economy with decreased caretaker stress and more vulnerable children in day-care, imprisonment of offenders, treatment of victims to prevent reactive abuse, decreased use of corporal punishment, earlier recognition and reporting, prevention programs including home visitors and less corporal punishment in schools. If early recognition is to occur there must be clearly defined and uniform laws that define abuse and the significant consequences to mandated reporters for failure to report. The laws must be concise, understandable and contain medically based definitions of abuse. A bruise should be considered a significant injury. The use of an instrument on a child, for any reason should be reportable as abusive. Society must be taught that a child's head and its contents are particularly susceptible to trauma. Heads should not be slapped, shaken, or struck. The purpose of a report of suspect maltreatment should be to obtain services for families. Without proper services, abuse will reoccur and victims will become victimizers. Any sexual act, including pornography, involving a child who is unable to give consent constitutes reportable sexual abuse. Recognition of what constitutes abuse would be simplified if all countries adopted laws that forbid corporal punishment in schools and homes. Parenting education, which offers alternatives to the use of corporal punishment and anger and stress management skills, should be universal and begun in preschool. In the older child, topics would include conflict management tactics, mate selection, child development, child health, and pregnancy planning. DISCUSSION: Professional knowledge of child maltreatment is inadequate. This multidisciplinary topic must be incorporated into the undergraduate and graduate curricula in medicine and other professions dealing with children. Child victims are unable to represent themselves. In most other childhood diseases the parents rise up in arms to lobby for their children's rights and raise money for research, professional education and clinical services. In child maltreatment, government and private organizations must take on this task. The valuable resources of Federal Public Health Services become available when child maltreatment is declared to be a disease. Other countries should emulate countries that have eliminated corporal punishment of children. Countries that do not protect children from maltreatment including the ravages of war must be seen as perpetrators of child maltreatment and answerable to the international community. One may adhere to the adage that one is not one's brother's keeper. This should never be applied to children. As the world's most precious resource, we must be the keepers of all children.

Child↗

Molecular analysis of the evolutionary significance of ultraviolet vision in vertebrates.

Many fish, amphibians, reptiles, birds, and some mammals use UV vision for such basic activities as foraging, mate selection, and communication. UV vision is mediated by UV pigments in the short wavelength-sensitive type 1 (SWS1) group that absorb light maximally (lambda max) at approximately 360 nm. Reconstructed SWS1 pigments of most vertebrate ancestors have lambda max values of approximately 360 nm, whereas the ancestral avian pigment has a lambda max value of 393 nm. In the nonavian lineage, UV vision in many modern species is inherited directly from the vertebrate ancestor, whereas violet vision in others has evolved by different amino acid replacements at approximately 10 specific sites. In the avian lineage, the origin of the violet pigment and the subsequent restoration of UV pigments in some species are caused by amino acid replacements F49V/F86S/L116V/S118A and S90C, respectively. The use of UV vision is associated strongly with UV-dependent behaviors of organisms. When UV light is not available or is unimportant to organisms, the SWS1 gene can become nonfunctional, as exemplified by coelacanth and dolphin.

Amino Acid Sequence↗

Parent-progeny recognition as a function of MHC odortype identity.

The several linked polymorphic genes of the MHC, which has been proposed as a prime determinant of sensed genetic individuality within species, is known to operate in mice by olfactory recognition in aspects of reproductive behavior that concern mate selection, thereby favoring outbreeding and heterozygosity, and also concern the maintenance of pregnancy. A single base-change can alter an individual MHC odortype, and the potential range of combinatorial MHC-determined odortypes is clearly vast. Following our findings that newborn mice already express their MHC odortype (which is detectable at 9 days of gestational age), we sought to determine whether MHC is involved in behavioral aspects of early development, such as rearing. In the studies presented herein, we report the ability and proclivity of mothers to recognize and preferentially retrieve syngeneic (genetically identical) pups from other pups differing only for MHC. Reciprocally, we report the ability of pups to recognize their familial environment, regardless of whether they had been nursed by their biological mothers or by foster mothers. Early learning experiences of the MHC environment are apparently a key element in survival, assuring maternal protection and promoting outbreeding.

Animals↗

Gene expression, cell localization, and evolution of rodent submandibular gland androgen-binding protein.

A small dimeric androgen-binding protein (Abp) secreted by mouse (Mus) submandibular salivary glands has been hypothesized to function in mate-selection. The alpha-subunit (Abpa) evolves rapidly under natural selection. However, cellular site(s) of synthesis, mode of function, and patterns of evolution of this biologically important protein are otherwise unknown. We used a radiolabeled riboprobe and in situ hybridization to mouse (Mus) Abpa mRNA to localize Abpa synthesis to submandibular gland acinar cells. We next used a quantitative fluorescent thermal cycler (real-time PCR) to determine relative expression levels (normalized with a constitutively expressed ribosomal gene [S15/rig; rat insulinoma gene]) in male, female, and sexually immature European striped field mice (Apodemus agrarius). We hypothesized that gender or age-related differences might occur in production of a salivary protein related to sexual selection, but found no significant differences within our sample. Finally, we also used reverse transcription-PCR of mRNAs isolated from submandibular salivary glands to determine the Abpa allele in the striped wood mouse and compare it to published information on the homologue in Mus musculus domesticus.

Amino Acid Sequence↗

Gender difference in mate preference among law students: divergence and convergence of criteria.

We examined six hypotheses derived from evolutionary theory regarding sex differences in mate-selection criteria. The subjects were 160 law students who viewed color photographs of live models that were paired with different status cues such as costume variation and descriptions of income and occupation. A multivariate analysis of variance and regression analyses revealed highly significant sex differences in the following responses: reported willingness to engage in unqualified sexual relations; reported willingness to have sexual relations with stimulus persons as compared with the willingness to engage in higher investment relationships such as dating and marriage; the effects of stimulus persons' status and physical attractiveness in determining thresholds of initial acceptability; and tradeoffs, that is the ability of high physical attractiveness to compensate for low status, and of high status to compensate for low physical attractiveness. Law students also responded to nine statements concerning prospective spouses' relative income, occupational prestige, and physical attractiveness. These responses exhibited sex differences consistent with those found in the experimental manipulation.

Adult↗

Secular changes in standards of bodily attractiveness in American women: different masculine and feminine ideals.

Silverstein, Peterson, and Perdue (1986) studied changes in curvaceousness of the models in Vogue magazine over time and found that curvaceousness was inversely correlated with American women's participation in higher education and the professions. In the present study, it was predicted that the male standard for women's bodily attractiveness would differ from the female standard and would change differently over time, based on evolutionary theory. Published data on the bodily curvaceousness of models in Playboy and Vogue and on Miss America winners were used to test this hypothesis. Although they did not differ on average, the male and female standards changed differently over time. There was less variation in the male standard, represented by Playboy and by Miss America winners, than in the female standard, represented by Vogue. Results suggest that cultural standards of attractiveness are influenced by an evolved psychology of mate selection that has implications for understanding changes in the standard of attractiveness and its relation to eating disorders.

Adult↗

Social status and the secondary sex ratio: new evidence on a lingering controversy.

Because women are more likely than men to use social status as a criterion in mate selection, evolutionary theory has led to the hypothesis that higher proportions of males will be born to parents of high social status than to parents of low status. To date, the research that has tested this deduction has not provided consistent support. This could be partly due to the small sample size in several of the studies. The present study tested the hypothesis using 6 different social status measures provided by more than 11,000 United States and Canadian college students. The offspring sex ratio was measured by asking the students their own sex plus that of each of their siblings. No evidence was found to support the hypothesis that parental social status has any significant effect on the sex ratio of offspring.

Canada↗

Reduced axial rotation in the spouses of sufferers from clinical idiopathic parkinsonism.

Axial rotation during recumbency was used to quantify the tendency towards parkinsonism with respect to one cardinal sign, brady/hypokinesia. Twenty-four elderly sufferers from idiopathic parkinsonism, their spouses, and 40 control subjects were studied. Significant differences in total angular displacement over 7 h were found between sufferers and their spouses (83% of grand mean) and between spouses of sufferers and controls (31%). These differences could not be accounted for by age or cognitive function. Moreover, the total angular displacement of the spouses was independent of whether they shared a bed with the sufferer. Neither the sufferers and their spouses, nor the 20 couples who constituted the control group, showed any relationship between partners with respect to angular displacement. These findings do not favour learned behaviour, or selective mating as an explanation of reduced movement in spouses of sufferers. Significantly more of the control couples had a single cardinal sign in both partners than expected on the basis of the frequency of a single sign in one partner. Environmental factors operating in adult life could be involved in the pathogenesis of parkinsonism.

Aged↗

Quantification of the cardinal signs of parkinsonism and of associated disability in spouses of sufferers.

Work on the causation of idiopathic parkinsonism is limited by relying on gross clinical definition and lack of studies in the old. A prognostic index for parkinsonism, based on hypo/bradykinesia of gait, had considerably higher values in spouses of 20 aged suffers, who had been cohabiting for about half a century, than in 40 controls. Postural abnormality, measured by standing sway and foot separation during walking, was also greater in these spouses. Marked differences remained after correction for relevant covariates. A blinded rigidity rating was greater in the spouses of sufferers, tremor rating was not. The differences found are difficult to explain by selective mating, learned or reactive behaviour. This suggests that environmental causative influences operate in adult life.

Aged↗

WinPop 2.5: software for representing population genetics phenomena.

The curriculum for genetics courses is shifting from a classical to a more molecular genetics focus, increasing the importance of subjects such as population genetics. Population genetics is a computational and statistical field that requires a good understanding of the nature of stochastic events. It is a difficult field for biology students with a limited mathematical background and there is a need for visualisation tools to facilitate understanding by the use of practical examples. WinPop provides students and researchers with a visual tool to allow the simulation and representation of population genetics phenomena. WinPop is a user-friendly software meant for use in population genetics courses and basic research. WinPop 2.5 contains six different modules that represent and simulate population genetics models. Genotype and allele frequencies are calculated under the different models: panmixia, genetic drift, assortative matings, selection, gene flow and mutation. The program's interface presents information in Cartesian graphics and isosceles triangular coordinate systems, allowing the user to save graphical and textual data output from the simulations. WinPop is developed in Visual Basic 6.0 and uses Windows 95 and higher. WinPop 2.5 can be downloaded from http://www.genedrift.org/winpop.php.

Algorithms↗

Gene diversity and female philopatry.

The effect of female philopatry on the apportionment of gene diversity within a population is evaluated. Even with random mate selection, the apportionment of gene diversity within and among social lineages (groups of related females) is inherently different than in classically defined demic groups. Considerable excess heterozygosity occurs within lineages without substantial changes in total or population heterozygosity. The proportion of genetic variance among lineages within the population was dependent on the lineage size and the number of male breeders per lineage. The greatest genetic differentiation among lineages was evident when there was one polygynous male breeding within a lineage of philopatric females, a common breeding tactic in mammalian social systems. The fixation indices depicting the genetic structure of the population were found to attain constant values after the first few generations despite the continuous loss of gene diversity within the population by genetic drift. Additionally, the change of gene correlations within individuals relative to the change within the population attains a state of dynamic equilibrium, as do the changes of gene correlations within lineages relative to the total and within individuals relative to within lineages. Comparisons of coancestries and fixation indices for philopatric versus randomly dispersing females indicate that philopatry and polygyny have probably not evolved independently and that promotion of gene correlations among adults rather than offspring has been of primary importance.

Animals↗

Risk of mortality and coronary heart disease by marital status in middle-aged men in The Netherlands.

Between 1972 and 1974, a cardiovascular screening survey was conducted in a stratified sample of 3365 men aged 45-59 in Rotterdam, the Netherlands. Follow-up data collected in 1982 were used to examine the association between marital status and mortality and coronary heart disease while adjusting for various control variables. Nonmarried men had significantly higher relative risks (RR) (95% confidence interval (CI)) of 1.7 (95% CI: 1.2-2.3) and 2.2 (95% CI: 1.2-4.2) for all-cause mortality and coronary mortality than the married. Never married men showed the most consistent relationships with all-cause and coronary mortality, with RR of 2.3 (95% CI: 1.6-3.4) and 2.9 (95% CI: 1.4-6.2) respectively. The RR for these endpoints among the widowed and divorced were all close to unity, except for the risk of coronary mortality among the widowed, which was 2.9 (95% CI: 0.9-10.2). Not being married also increased the risk for fatal and total reinfarction, with RR of 3.6 (95% CI: 1.4-9.1) and 2.5 (95% CI: 1.1-5.6) respectively. The results suggest that in middle-aged Dutch males, the health consequences of not being married may differ for the never married, divorced, and widowed. Selective mating, differential lifestyles or health habits, and lack of social integration were offered as possible explanations.

Coronary Disease↗

Age at marriage, sex-ratios, and ethnic heterogamy.

"This paper focuses on the effects of age at marriage and the sex-ratio on patterns of ethnic homogamy among Israeli women. We hypothesize that later marriages are more likely than early marriages to be heterogamous as the 'marriage market' shifts from school to the work-place. By the same token, when facing severe marriage squeezes women will be forced to out-marry. Employing data from the 1983 census, we model mate selection of women from Afro-Asian and Euro-American origin in various birth-cohorts. The results do not fully support our hypotheses: we find that in and of itself, age at marriage does not enhance ethnic heterogamy."

Asia↗

Mouse models for deafness: lessons for the human inner ear and hearing loss.

In the field of hearing research, recent advances using the mouse as a model for human hearing loss have brought exciting insights into the molecular pathways that lead to normal hearing, and into the mechanisms that are disrupted once a mutation occurs in one of the critical genes. Inaccessible for most procedures other than high-resolution computed tomography (CT) scanning or invasive surgery, most studies on the ear in humans can only be performed postmortem. A major goal in hearing research is to gain a full understanding of how a sound is heard at the molecular level, so that diagnostic and eventually therapeutic interventions can be developed that can treat the diseased inner ear before permanent damage has occurred, such as hair cell loss. The mouse, with its advantages of short gestation time, ease of selective matings, and similarity of the genome and inner ear to humans, is truly a remarkable resource for attaining this goal and investigating the intrigues of the human ear.

Animals↗