Analysis of Eigen’s equations for selection of biological molecules with fluctuating mutation rates

In this paper we consider Eigen’s equations for the selection and evolution of self-instructing, macromolecular systems. We construct exact, asymptotic solutions for the equations when the rate coefficients and error distributions are considered as functions of time. Implications for selection are discussed.     

Natural self-organization of polynucleotides and polypeptides in protobiogenesis: Appearance of a protohypercycle

Basic thermal polyamino acids or proteinoids have been reported to be catalytic for both self-instructing polymerization of amino acids and internucleotide synthesis. We show theoretically that a complex suspension of thermal proteinoids, free amino acids, nucleotides and ATP as an energy source can exhibit an evolutionary character. The suspension can produce a prototype of Eigen's hypercycle, or protohypercycle, for which translation proceeds from amino acid to nucleotide. The protohypercycle is suggested to be an evolutionary precursor of the hypercycle, in which translation is from nucleotide to amino acid. The possibility that the Fox-Nakashima microsphere containing both lysine-rich and acidic proteinoids may work as a model of a protohypercycle is considered.     

Sexual selection for a handicap: A critical analysis of Zahavi's model

In Zahavi's model, females with a preference for conspicuous males, or for males with some other kind of handicap to survival, gain an advantage because their offspring have an increased fitness as a result of the more intense selection of the handicapped males. To gain such an advantage, however, extremely intense selection would have to act on the handicapped males and almost equally intense selection on the others. In realistic cases, the intensities of selection required by Zahavi's model cannot be achieved. Two premises implied by the model are false. The first is the assumption that selection continues to produce an advantage for the females with the preference. Selection cannot continue to do this, however: the fitness of the handicapped males cannot increase indefinitely, and any initial advantage that might be produced by extremely intense selection must soon be lost and turn to disadvantage. In the second premise, selection is assumed to favour the same combination of characters in both handicapped and non-handicapped males. This is also false: disruptive selection would favour different combinations of characters in these individuals; the combination of characters favourable to handicapped individuals would be unfavourable when passed on to non-handicapped offspring thus eliminating any advantage that the females with the preference might gain. The premises and logic of Zahavi's model are therefore false.     

Cue-based estimates of reproductive value explain women's body attractiveness

Women's body attractiveness is influenced by specific anthropometric cues, including body mass index (BMI), waist-to-hip ratio (WHR), waist-to-stature ratio (WSR), and shoulder-to-waist ratio (SWR). Despite the existence of multiple functional hypotheses to explain these preferences, it remains unclear which cue-based inferences are most influential in regulating evaluations of women's body attractiveness. We argue that (i) the common link to the morphological cues that influence women's body attractiveness is that they all reliably indicate high reproductive value (as defined by youth and low parity); and (ii) ancestrally, selection pressures related to tracking between-women differences in reproductive value would have been among the strongest acting on adaptations for body evaluation. An empirical study then tested the resulting prediction that cue-based estimates of reproductive value function as powerful regulators of women's body attractiveness judgments. Subjects viewed standardized photos of women in swimsuits (with heads obscured), and were assigned to either estimate components of their reproductive value (age or number of offspring) or rate their attractiveness. Structural equation modeling revealed that a latent variable capturing estimated reproductive value was almost perfectly correlated with a latent variable capturing body attractiveness. Moreover, unique associations of women's BMI, WHR, and WSR with their body attractiveness were entirely mediated via estimated reproductive value. These findings provide strong support for the longstanding hypothesis that women's body attractiveness is primarily explained by cue-based estimates of reproductive value – expected future utility as a vehicle of offspring production.     

The primacy of trust within romantic relationships: Evidence from conjoint analysis of HEXACO-derived personality profiles

Mate preference research often focuses on traits that indicate a romantic partner's personal worth (e.g., their physical attractiveness, resource potential) rather than their tendency to leverage that worth for mutual vs. zero-sum benefit (i.e., their trustworthiness). No one has assessed the contribution of trustworthiness to perceived mate value relative to other personality dimensions. Here we examined the desirability of a partner's trustworthiness relative to five other personality indicators of mate quality during initial partner selection. Participants (n = 918) ranked multivariate partner profiles constructed from the HEXACO model of personality (i.e., honesty-humility, emotionality, extraversion, agreeableness, conscientiousness, and openness to experience) and provided partner ratings for each trait. Using conjoint analysis, we found that honesty-humility influenced participants' ranking decisions substantially more than each other characteristic (all Cohen's ds > 0.62). This was true for both long- (i.e., committed) and short-term (i.e., purely sexual) partner evaluations, though honesty-humility was relatively more important for long- vs. short-term contexts. There were no sex differences. A different pattern, including sex differences, emerged for partner ratings. Based on these findings, we hypothesize that the challenge of avoiding romantic interpersonal predation may have been a relatively stronger selection pressure during the evolution of human mate preference than has the challenge of identifying other valuable partner traits.     

Microhabitat selection for singing and other behaviour in great tits, Parus major: Some visual and acoustical considerations

Territorial male great tits (Parus major L.) usually forage on the ground, sing from perches with a mean height of 9.3 m, and perform most other activities between 2 and 4 m. Analyses of their habitat's visual and acoustical stratification indicate that great tits sing from high perches to make themselves hard to locate visually rather than to make their songs carry farther. The birds' selection of inconspicuous singing spots is further substantiated by their striking preference for hawthorn trees, which have an extremely dense crown and produce leaves very early in the year.     

Crassostrea gryphoides et C. gingensis (Schlotheim, 1813) deux expressions morphologiques d'une même espèce (Miocène, Bivalvia)

The assemblages of Crassostrea gryphoïdes of the Loupian's quarry is constitued of differents morphotypes which result of ecological effects (population density, locality and position in the assemblage). The selection of individuals with her life position shows two lots of Ostreidae the morphology of which is statistically different. The observations about Crassostrea of outcrops of Rhone's Valley and Touraine confirm the relations between position (liable to population's density) and morphology. The two types which are point out are often recognize as different species describe by E.F. von Schlotheim, 1813: Crassostrea gryphoïdes and Crassostrea gingensis. Therefore this two species must be consider as synonymous.     

The intensity of sexual selection in relation to male sexual behaviour,female choice,and sperm precedence

In this paper we define sexual selection on males as the variance in numbers of mates per male and show how the intensity of this selection is affected by male sexual behaviour, female choice, sex ratio, and modes of sperm precedence. This definition coincides with Darwin's conception of sexual selection but differs from some post-Darwinian views. For systems of single-male paternity, we show that the intensity of total selection on male reproductive success equals the intensity of natural selection on female fertility, times the sex ratio, plus the intensity of sexual selection on males. The absolute intensity of sexual selection is unaffected by the system of sperm precedence. The application of the results to field studies is discussed.     

Alzheimer's disease and Down's syndrome: Sharing of a unique cerebrovascular amyloid fibril protein

The cerebrovascular amyloid protein from a case of adult Down's syndrome was isolated and purified. Amino acid sequence analysis showed it to be homologous to that of the β protein of Alzheimer's disease. This is the first chemical evidence of a relationship between Down's syndrome and Alzheimer's disease. It suggests that Down's syndrome may be a predictable model for Alzheimer's disease. Assuming the β protein is a human gene product, it also suggests that the genetic defect in Alzheimer's disease is localized on chromosome 21.     

Breeding adaptations of Franklin's gull (larus pipixcan) to a marsh habitat

The behaviour and ecology of Franklin's gull were studied at Agassiz National Wildlife Refuge in northwestern Minnesota to determine the adaptations of the species for nesting in marshes. Two factors seemed to be important in colony site selection: cattail dispersion pattern and cattail density. Franklin's gulls prefer to nest in cattail areas closest to open water. The number of nests per unit area decreased as cattail density increased. Nest site selection is dependent on aggression and visibility. Visibility from nest level is the result of cattail placement and height. The distance between nests was directly correlated with visibility. Aggression by gulls on nests was lowered experimentally by decreasing visibility and raised by increasing visibility. Nest platforms were constructed of cattail material, and were attached to cattail stems. Nest material was added to the nests throughout the incubation and brooding period. Material was usually added following nest relief. The egg laying period was from 6 to 28 May. There was more synchrony of egg laying in sub-areas of the colony than in the colony as a whole. Successive eggs in clutches were laid at 24- to 48-hr intervals. The distance between nests decreased during the season as pairs filled in areas that were not defended. Territorial pairs defended an area up to 10 m from their stations prior to egg laying, but defended only the area within 3 m of their nests during incubation. Both members of pairs incubated the eggs and cared for the young. The incubation period was 24 days. The primary predators on adults and young were marsh hawk, great horned owl and mink. Franklin's gulls do not eat eggs or young of gulls. Adults fed on earthworms, insects and grain. Most marked adults fed within 16 km of the colony. Chicks were fed primarily on earthworms. The hatching period was from 30 May to 21 June. Chicks of all ages tested on a visual cliff apparatus were able to perceive the drop. Chicks tested on a 30-degree incline apparatus walked up it when 6 days old and younger, and walked down at 12 days of age and older. Brood mobility was less than in ground nesting species of gulls. In an undisturbed colony the chicks remained on the nest platforms until they were 25 to 30 days old although they were capable of swimming shortly after hatching. Individual recognition between parents and chicks appeared later in this species than in ground-nesting gulls. Adults accepted alien chicks (experimentally exchanged) that were younger than about 14 days old until their own chicks were over that age. Adults accepted larger and older broods than their own, as well as broods of mixed ages. Chicks began to react differently to strange adults at about 16 days of age. The breeding chronology of Franklin's gull is compressed when compared to that of other gulls. Possible selection pressures affecting this synchrony are discussed. The behaviour of the marsh-nesting Franklin's gull is compared with that of typical ground-and cliffnesting gulls; the possibility that the ancestral gull may have been a marsh nester is discussed.     

Sex differences in political leadership in an egalitarian society

We test the contribution of sex differences in physical formidability, education, and cooperation to the acquisition of political leadership in a small-scale society. Among forager-farmers from the Bolivian Amazon, we find that men are more likely to exercise different forms of political leadership, including verbal influence during community meetings, coordination of community projects, and dispute resolution. We show that these differences in leadership are not due to gender per se but are associated with men's greater number of cooperation partners, greater access to schooling, and greater body size and physical strength. Men's advantage in cooperation partner number is tied to their participation in larger groups and to the opportunity costs of women's intrahousehold labor. We argue these results highlight the mutual influence of sexual selection and the sexual division of labor in shaping how women and men acquire leadership.     

Comparison of the in vivo clearance of des-AA and des-AABB rat fibrin monomers prepared by different methods

Solubilization of fibrin monomers (Fm's) is usually performed with dilute acetic acid, urea or sodium bromide. These solvents can affect the biological properties of Fm's. Therefore we describe a new method to keep Fm's in solution, under milder conditions i.e. by generating them in Dcate solutions and avoiding non-physiological conditions. The in vivo behaviour of iodinated rat Fm's injected in rats and prepared by this new method was compared with that of Fm's dissolved in acetic acid, urea or sodium bromide.Fm's prepared in Dcate solutions accumulate rapidly, within 10 minutes after injection, in all organs tested, predominantly in kidney, liver and lung, probably by interaction with endothelial cells. The blood radioactivity remains nearly constant during the first 90 minutes and decreases thereafter exponentially. Fm's dissolved in sodium bromide behave similarly. However, Fm's dissolved in acetic acid or urea behave differently and do not accumulate in organs. This suggests that Fm's loose their capability to accumulate in organs and probably to interact with endothelial cells when they have been dissolved in acetic acid or urea.The slow exponential clearance phase does not differ significantly between the various Fm's and their $\text{T}\text{1}\text{2'S}$ are estimated to lie between 5 and 7 hours.     

Gamma-ray-induced dominant mutations that cause skeletal abnormalities in mice I. Plan,summary of results and discussion

Male mice were exposed to 100 R + 500 R γ-rays (60 R/min) with a 24-h fractionation interval. Skeletons of F₁ sons were examined for abnormalities, and, if any were found, the skeletons of their descendants were also examined. Of 2646 sons from treated spermatogonia, 37, or 1.4%, were diagnosed as carriers of autosomal dominant mutations affecting the skeleton, 31 by breeding tests, and six by other criteria for identifying mutations in F₁'s having no progeny. Earlier experiments by U.H. Ehling on dominant skeletal mutations indicated the spontaneous mutation frequency to be small relative to the induced frequencies from radiation doses similar to that used in this experiment. The mutation rate of 1.4% now reported probably includes some spontaneous mutations; however, any error in overestimating the induced rate made by taking all mutations as induced is probably more than counterbalanced by some mutations not being scored, mainly because of incomplete penetrance or poor viability.Many mutations caused a large number of anomalies in different regions of the skeleton. Most regions of the skeleton were affected by at least one mutation, and the mutations had incomplete penetrance for some or all of their effects. Three of the mutations affected skeletal size only.If certain assumptions are made, these skeletal data can be used to derive an estimate of induced genetic damage from dominant mutations affecting all parts of the body. When this is applied to man, the resultant risk estimate is not inconsistent with that made for dominant and irregularly inherited disease by the BEIR Committee, by use of the doubling-dose method. Since most of the mutations can be characterized as models of irregularly inherited conditions in man, the data directly relate to the controversy over the relative importance of mutation pressure and balanced selection in maintaining man's large burden of irregularly inherited disease. Contrary to a recent hypothesis by H.B. Newcombe that man's large burden of irregularly inherited disease is maintained almost exclusively by balanced selection, these results suggest that at least an important fraction of the irregularly inherited conditions are maintained by mutation pressure. Therefore, this finding does not support the major changes in the estimate of genetic hazard to man that would be required on the basis of Newcombe's hypothesis.     

On the Spectrum of Prebiotic Chemical Systems

We reexamine Eigen’s paradox using the asymptotic limit theorems of information theory. Applying the homology between information source uncertainty and free energy density, under rate distortion constraints, the error catastrophe emerges as the lowest energy state for simple prebiotic systems without error correction. Invoking the usual compartmentalization – i.e., ‘vesicles’ – and using a Red Queen argument, suggests that information crosstalk between two or more properly interacting structures can initiate a coevolutionary dynamic having at least two quasi-stable states. The first is a low energy realm near the error threshold, and, depending on available energy, the second can approach zero error as a limit. A large deviations argument produces jet-like global transitions which, over sufficient time, may enable shifts between the many quasi-stable modes available to more complicated structures, ‘locking in’ to some subset of the various possible low error rate chemical systems, which become subject to development by selection and chance extinction. Energy availability, according to the model, is thus a powerful necessary condition for low error rate replication, suggesting that some fundamental prebiotic ecosystem transformation entrained reproductive fidelity. This work, then, supports speculation that our RNA/DNA world may indeed be only the chance result of a very broad prebiotic evolutionary phenomenon. Processes in vitro, or ex planeta, might have other outcomes.     

TIMA Part 2. TIMA-based instructive evolution of macromolecules and organs and structures

In extending a previous paper (TIMA Part 1, Wassermann, 1982) “template induced molecular assembly” (TIMA) is being further explored. It is suggested that TIMA could first have evolved proteins without coevolution of mRNA-like systems, in the absence of tRNAs. Some of these early proteins could, by self-assembly, have built up ribosomes. Ribosomes jointly with amino acids could have served as assembly templates for the TIMA-based evolution of tRNAs. Once tRNAs had evolved, TIMA could have participated, via a modified Mekler (1967) mechanism, in the evolution of new proteins and the coevolution of corresponding mRNA-like strands. TIMA also requires gene duplications and/or random mutations of DNA, to produce partial matching by duplicated and/or randomized DNA sequences of TIMA-generated cDNA which is complementary to the mRNA-like strands. The cDNA could then become incorporated by crossover into the position of the partially matching DNA sequences of, say, duplicate genes in genomes of germ-line cells. Since one requires only partial matching between duplicate (and/or randomly generated) DNA and non-randomly, TIMA-generated cDNA, TIMA theory avoids the need to assume (as in the Baldwin effect) that complete genes were randomly evolved. While rejecting crude Lamarckism, TIMA equally avoids the assumption that genes evolved only by combined random events, gene duplications, and adaptive selection. The resulting theory explains typical pseudo-exogenous adaptations via TIMA. Darwinian selection—now in the guise of “molecular selection” (and favourable environmental adaptive selection where present)—combined with TIMA could account for Waddington's “genetic assimilation”, thereby conceding Lamarck's notion that the environment can help to model heredity (while rejecting crude Lamarckism).     

The effect of multiple inseminations on the evolution of social behaviors in diploid and haplo-diploid organisms

Using a classical population genetic model, the necessary conditions for the spread of genes that determine social behaviors and the rate of spread of these genes are derived. The influence of 1, 2, 3, or k inseminations per female on these conditions is investigated for both diploid and haplodiploid organisms. These results are then extended to a population in which there are arbitrary variations among females in their numbers of mates. These results do not depend upon assuming equal paternity by all inseminating males; the effects of sperm competition and unequal paternity are also derived. The rates and conditions for social evolution in these groups of complex composition are discussed in relation to Hamilton's rule.For all models, the total change in gene frequency, Δq, is partitioned into two components: (1) $\text{Δq}{}_{\mathrm{I}}$, the change in gene frequency caused by selection within groups; this component is always negative, illustrating that individual selection always operates against the evolution of social behaviors; and (2) Δq_G, the change in gene frequency caused by selection between groups; this component is generally positive. Hamilton's rule is shown to specify the necessary and sufficient conditions for $\text{Δq}{}_{\mathrm{G}}\text{> |}\text{Δq}{}_{\mathrm{I}}\text{|}$, that is, for selection among kin groups to over-ride individual selection within kin groups.     

Coefficients of relationship and coefficients of relatedness in kin selection: A covariance form for the RHO formula

Hamilton used the coefficient of relationship to predict the direction of selection acting on “genes for altruism” in a theoretical model. The sense (direction) of the inequality determined the direction of selection. But, paradoxically, Hamilton pointed out that traditional formulae for the coefficient of relationship cannot be evaluated during directional selection. Hamilton escaped the paradox by assuming very weak selection.Later papers, including three by Hamilton, used other coefficients in place of the coefficient of relationship in the inequality. Thus inbreeding and directional selection could be handled in exact models. This paper tries to clarify the differences between the various coefficients and to point out an error in one of the author's previous works: Namely to state that there is analytical proof that the regression coefficient is a special case of a coefficient called ? whereas the earlier paper claimed only numerical verification was possible.Since the symbol “?” is also used to denote the correlation coefficient, it is suggested here that the p of kin selection be given a new name.     

No evidence that facial attractiveness,femininity, averageness,or coloration are cues to susceptibility to infectious illnesses in a university sample of young adult women

Previous reports that women with attractive faces are healthier have been widely cited as evidence that sexual selection has shaped human mate preferences. However, evidence for correlations between women's physical health and facial attractiveness is equivocal. Moreover, positive results on this issue have generally come from studies of self-reported health in small samples. The current study took standardized face photographs of women who completed four different health questionnaires assessing susceptibility to infectious illnesses (N?=?590). Of these women, 221 also provided a saliva sample that was assayed for immunoglobulin A (a marker of immune function). Analyses showed no significant correlations between rated facial attractiveness and either scores on any of the health questionnaires or salivary immunoglobulin A. Furthermore there was no compelling evidence that objective measures of sexual dimorphism of face shape, averageness of face shape, or facial coloration were correlated with any of our health measures. While other measures of health may yet reveal robust associations with facial appearance, these null results do not support the prominent and influential assumption that women's facial attractiveness is a cue of young adult women's susceptibility to infectious illnesses, at least in our study population.     

Simplifying principles for chemical and enzyme reaction kinetics

Tihonov's Theorems for systems of first-order ordinary differential equations containing small parameters in the derivatives, which form the mathematical foundation of the steady-state approximation, are restated. A general procedure for simplifying chemical and enzyme reaction kinetics, based on the difference of characteristic time scales, is presented. Korzuhin's Theorem. which makes it possible to approximate any kinetic system by a closed chemical system, is also reported. The notions and theorems are illustrated with examples of Michaelis-Menten enzyme kinetics and of a simple autocatalytic system. Another example illustrates how the differences in the rate constants of different elementary reactions may be exploited to simplify reaction kinetics by using Tihonov's Theorem. All necessary mathematical notions are explained in the appendices. The most simple formulation of Tihonov's 1st Theorem ‘for beginners’ is also given.     

Hydroxylation of para-chlorotoluene by model complexes of cytochrome P-450

Hydroxylation of p-chlorotoluene with heminthiol complexes, Fenton's system and Udenfriend's system was studied and the complexes assessed as models of cytochrome P-450 monooxygenases. Five species of possible hydroxylation products of p-chlorotoluene, namely, p-chlorobenzyl alcohol, 2-chloro-5-methylphenol, p-chlorobenzaldehyde, 4-chloro-2-methylphenol and 5-chloro-2-methylphenol, were studied using high performance liquid chromatography. The oxidation reactions were characterized by the yields of hydroxylation products and the product ratio. The system consisting of hemin and cysteine ethyl ester as well as Udenfriend's system gave relatively high hydroxylation yields and the former only induced a methyl migration during hydroxylation (methyl NIH shift). However, neither Fenton's nor Udenfriend's systems induced a methyl NIH shift. The hemin-thiol complex is thus concluded to be a good chemical model of cytochrome P-450 monooxygenases.