The norm for perceived husband superiority: A cause of human assortative marriage

Abstract

I have suggested that human assortative marriage for a number of variables is partially caused by behavior in accordance with two norms. Epstein and Guttman (1987) have suggested that there is no empirical evidence for these norms. In this note evidence is reviewed for the norm of perceived husband‐superiority. Others have shown that the evidence for this norm is strong in regard to height, and it is shown here that the evidence is strong also in regard to age. Evidence for the norm seems suggestive in regard to IQ, education, and social class, and nonexistent in regard to physical attractiveness. With respect to height, it seems that the magnitude of the correlation between spouses is associated with the size of the breeding population to which they belong. Thus, it seems likely that the hypothesized norms are learned rather than genetically coded.     

Ethnically assortative marriage in the rural population of Tatarstan

Ethnically assortative marriage rates have been calculated for Tatars (1.16) and Russians (8.37) on the basis of 14 729 marriage records made in 1990–2000 in seven raions of Tatarstan (Arsky, Atninsky, Drozhzhanovsky, Alkeevsky, Musljumovsky, Aktanyshsky, and Baltasinsky). The outbreeding rate of Tatars (5.35%) has been found to be lower than in a number of other populations studied in this respect.     

Panmixia postponed: ancestry-related assortative mating in contemporary human populations

A study of two different populations reveals that in both the choice of a spouse is non-random not only in respect of broad ethnic group but also in regard to specific ancestries within that group. The cause of this surprising bias remains unclear.     

The problem of the adaptive norm in human populations

The results of some investigations recently fulfilled in the framework of population-genetics approach to the problem of adaptive norm in human populations are summarized in this review. The main items considered are: methods of identification of morphologically "average" phenotypes, the role of stabilizing selection in maintaining the population adaptive norm, the problem of joint variation of monogenic and polygenic traits ant its relevance to "norm" and pathology. The significance of the concept of adaptive norm for preventive medicine and genetic monitoring is discussed.     

Dying for a cause: invertebrate genetics takes on human neurodegeneration

If invertebrate neurons are injured by hostile environments or aberrant proteins they die much like human neurons, indicating that the powerful advantages of invertebrate molecular genetics might be successfully used for testing specific hypotheses about human neurological diseases, for drug discovery and for non-biased screens for suppressors and enhancers of neurodegeneration. Recent molecular dissection of the genetic requirements for hypoxia, excitotoxicity and death in models of Alzheimer disease, polyglutamine-expansion disorders, Parkinson disease and more, is providing mechanistic insights into neurotoxicity and suggesting new therapeutic interventions. An emerging theme is that neuronal crises of distinct origins might converge to disrupt common cellular functions, such as protein folding and turnover.     

Some multiallele partial assortative mating systems for a polygamous species

The consequences of preferential mating in the presence of partial assortative and sexual selection mechanisms are ascertained for a two-allele one-locus trait involving two phenotype classes C₁ = {all homozygotes} and C₂ = {heterozygotes}. Relevant biological cases may include Burley (1977, Proc. Nat. Acad. Sci. USA 74, 3476–3479), Wilbur et al. (1978, Evolution 32, 264–270), and Singh and Zouros (1978, Evolution 32, 342–353). When the preference rate for the heterozygote exceeds that for homozygotes, it is established that the unique stable state is the central Hardy-Weinberg equilibrium. The rate of approach is faster with sexual selection than for the corresponding model of assortative mating. When the preference rates favor the homozygotes then in this symmetric model of sexual selection two asymmetric Hardy-Weinberg polymorphisms can evolve, and which succeeds depends on initial conditions. The models are also analyzed with natural selection acting on phenotypes superimposed on assortative mating. In this case we can have up to three coexisting stable states involving both fixation alternatives and a central polymorphism. The corresponding model with sexual selection maintains either the central equilibrium as in assortative mating or two asymmetric polymorphic equilibria.     

The genome and the nucleus: a marriage made by evolution

Genomes are housed within cell nuclei as individual chromosome territories. Nuclei contain several architectural structures that interact and influence the genome. In this review, we discuss how the genome may be organised within its nuclear environment with the position of chromosomes inside nuclei being either influenced by gene density or by chromosomes size. We compare interphase genome organisation in diverse species and reveal similarities and differences between evolutionary divergent organisms. Genome organisation is also discussed with relevance to regulation of gene expression, development and differentiation and asks whether large movements of whole chromosomes are really observed during differentiation. Literature and data describing alterations to genome organisation in disease are also discussed. Further, the nuclear structures that are involved in genome function are described, with reference to what happens to the genome when these structures contain protein from mutant genes as in the laminopathies. Review related to the 15th International Chromosome Conference (ICC XV), held in September 2004, Brunel University, London, UK     

The endocannabinoid signaling system: a marriage of PUFA and musculoskeletal health

The role of diet in health and diseases related to muscle and bone has been an area of active study. Recently, endocannabinoids (EC), endogenous derivatives of arachidonic acid, an omega-6 (n-6) polyunsaturated fatty acid (PUFA), have been discovered to play regulatory roles in bone mass and muscle energy metabolism. This signaling system consists of the G-protein coupled cannabinoid receptors, CB1 and CB2, expressed in central and peripheral tissues and cells, which are variably activated by the production and on demand release of endogenous and synthetic agonists and antagonists. We propose that the balance between omega-6 and omega-3 (n-3) PUFA is an important modifier for the activation and suppression of endocannabinoid receptors and therefore, downstream signaling actions in cells. The potential of dietary PUFA to regulate this signaling system to influence the metabolic and physiological outcomes favorable to musculoskeletal health is the purpose of this review. The important role of n-3 PUFA in metabolic and physiological processes that attenuate muscle and bone loss under conditions of disease and stress is one aspect described herein. In this review, we first introduce the EC agonists (ligands) and their receptors (CB1 and CB2) and the general actions of EC signaling in various organs and systems. Second, we describe EC signaling in bone and muscle and how dietary PUFA influence the levels of endogenous agonists. Third, we discuss the potential implications of how dietary PUFA impact this system to minimize muscle atrophy and osteopenia and support healthy muscle development and bone modeling.     

A model for the evolution of assortative mating

Abstract: Many animals and plants show a correlation between the traits of the individuals in the mating pair, implying assortative mating. Given the ubiquity of assortative mating in nature, why and how it has evolved remain open questions. Here we attempt to answer these questions in those cases where the trait under assortment is the same in males and females. We consider the most favorable scenario for assortment to evolve, where the same trait is under assortment and viability selection. We find conditions for assortment to evolve using a multilocus formalism in a haploid population. Our results show how epistasis in fitness between the loci that control the focal trait is crucial for assortment to evolve. We then assume specific forms of assortment in haploids and diploids and study the limiting cases of selective and nonselective mating. We find that selection for increased assortment is weak and that where increased assortment is costly, it does not invade.