On the origins of narrative

Stories consist largely of representations of the human social environment. These representations can be used to influence the behavior of others (consider, e.g., rumor, propaganda, public relations, advertising). Storytelling can thus be seen as a transaction in which the benefit to the listener is information about his or her environment, and the benefit to the storyteller is the elicitation of behavior from the listener that serves the former’s interests. However, because no two individuals have exactly the same fitness interests, we would expect different storytellers to have different narrative perspectives and priorities due to differences in sex, age, health, social status, marital status, number of offspring, and so on. Tellingly, the folklore record indicates that different storytellers within the same cultural group tell the same story differently. Furthermore, the historical and ethnographic records provide numerous examples of storytelling deliberately used as a means of political manipulation. This evidence suggests that storyteller bias is rooted in differences in individual fitness interests, and that storytelling may have originated as a means of promoting these interests.     

On the origins of esterases

Comparisons among the primary sequences of five cloned eukaryotic esterases reveal two distinct lineages, neither bearing any significant overall sequence similarity to the functionally related serine protease multigene family. We have not eliminated the possibility that the esterases may have residual conformational similarities to the serine proteases. However, our profile analysis and analyses of the predicted conformations of the esterases reveal little similarity to the serine proteases. Four of the esterase proteins share 27%-53% overall sequence similarity and evidence of a catalytic mechanism involving the same Arg- Asp-Ser or His-Asp-Ser charge relay. We propose that these four esterases, three of them cholinesterases, form part of a multigene family essentially separate from the serine proteases.      

Do the evolutionary origins of our moral beliefs undermine moral knowledge?

According to some recent arguments, (Joyce in The evolution of morality, MIT Press, Cambridge, 2006; Ruse and Wilson in Conceptual issues in evolutionary biology, MIT Press, Cambridge, 1995; Street in Philos Studies 127: 109–166, 2006) if our moral beliefs are products of natural selection, then we do not have moral knowledge. In defense of this inference, its proponents argue that natural selection is a process that fails to track moral facts. In this paper, I argue that our having moral knowledge is consistent with, (a) the hypothesis that our moral beliefs are products of natural selection, and (b) the claim (or a certain interpretation of the claim) that natural selection fails to track moral facts. I also argue that natural selection is a process that could track moral facts, albeit imperfectly. I do not argue that we do have moral knowledge. I argue instead that Darwinian considerations provide us with no reason to doubt that we do, and with some reasons to suppose that we might.     

On the origins of nitric oxide

Nitric oxide (NO) is widely recognized for its role as signaling compound. However, the metabolic mechanisms that determine changes in the level of NO in plants are only poorly understood, despite this knowledge being crucial to understanding the signal function of NO. To date, at least seven possible pathways of NO biosynthesis have been described for plants, although the molecular and enzymatic components are resolved for only one of these. Currently, this represents the most significant bottleneck for NO research. In this review, we provide an overview of the multiplicity of NO production and scavenging pathways in plants. Furthermore, we discuss which areas should be focused on in future studies to investigate the origin of fluctuations in the level of NO in plants.     

On the origins of triterpenoid skeletal diversity

The triterpenoids are a large group of natural products derived from C(30) precursors. Nearly 200 different triterpene skeletons are known from natural sources or enzymatic reactions that are structurally consistent with being cyclization products of squalene, oxidosqualene, or bis-oxidosqualene. This review categorizes each of these structures and provides mechanisms for their formation.     

On the origins of New World paleopathology

Many of the lesions found in American Indian bones do not resemble those found in human bones from the Old World, suggesting that the American Indians suffered from a distinct group of illnesses. If Old World pathogens did not follow man to the New World, what were the sources of pre-Columbian Indian diseases? As in the Old World, humans were susceptible to diseases endemic in the local animal populations. Exposure to these diseases varied with culturally conditioned animal contacts. As the New World population increased, the probability for disease increased, to the point where it is likely that even in pre-Columbian times, disease rather than war or climatic changes may have been a major influence in changing settlement patterns. The generalization that the only Old World plants and animals found in the New were those brought by man seems to hold as true for the pre-Columbian disease organisms as it is for larger forms of life.     

On the origins of genetic variants.

Two contrasting mechanisms responsible for the creation of genetic variants are described: one is the manifestation of the limited accuracy of the cellular machinery for DNA replication, the other results from the ability of cells to repair damaged DNA. Replication-dependent variants and those caused by episodical DNA damage enhance the probability that a small fraction of a cell population may survive a sudden (physical or biological) change of environmental conditions. Replication-independent variants arise during persistent but not immediately lethal stress (e.g. starvation) of a non-dividing population. The variants observed under these conditions are of selective advantage because they are able to cope with the particular stress situation. The molecular basis of their creation is a matter of intensive debate.     

On the origins of ultra-fine anaphase bridges

Comment on: Chan KL, Palmai-Pallag T, Ying S, Hickson ID. Replication stress induces sister-chromatid bridging at fragile site loci in mitosis. Nat Cell Biol 2009; 11:753-60.     

On the origins of arrestin and rhodopsin

Background  

G protein coupled receptors (GPCRs) are the most numerous proteins in mammalian genomes, and the most common targets of clinical drugs. However, their evolution remains enigmatic. GPCRs are intimately associated with trimeric G proteins, G protein receptor kinases, and arrestins. We conducted phylogenetic studies to reconstruct the history of arrestins. Those findings, in turn, led us to investigate the origin of the photosensory GPCR rhodopsin.     

On the origins of the Mendelian laws

The two laws usually attributed to Mendel were not considered as laws by him. The first law, the law of independent segregation occurs in Mendel's paper as an assumption or hypothesis. Hugo de Vries refers to this as a law discovered by Mendel. This appears to be the first use of an expression equivalent to Mendel's law. In his paper de Vries did not associate the observable characters with structures having a causitive role. That was done by Correns, who transformed the law of segregation of characters into a law of the segregation of anlagen. The second law, the law of independent assortment, is present in embryonic form in Mendel's paper. Here the independent assortment of characters appears as a secondary conclusion to a series of experiments involving several pairs of traits. Mendel repeats the primary conclusion later in the paper but not the secondary one. This leads us to believe that he considered the secondary conclusion as of lesser importance. We note in this context that the 9:3:3:1 ratio commonly associated with the idea of independent assortment, and attributed to Mendel, also does not occur in his paper. A careful reading of the papers of his discoverers shows it was Correns who first drew attention to this ratio. However, he did not formulate the second Mendelian law even though it was clearly implied. Neither was it stated by de Vries. Indeed, the first clear separation of the two laws and the naming of the second law was by T. H. Morgan some 13 years later.     

On the origins of sexual dimorphism in butterflies

The processes governing the evolution of sexual dimorphism provided a foundation for sexual selection theory. Two alternative processes, originally proposed by Darwin and Wallace, differ primarily in the timing of events creating the dimorphism. In the process advocated by Darwin, a novel ornament arises in a single sex, with no temporal separation in the origin and sex-limitation of the novel trait. By contrast, Wallace proposed a process where novel ornaments appear simultaneously in both sexes, but are then converted into sex-limited expression by natural selection acting against showy coloration in one sex. Here, we investigate these alternative modes of sexual dimorphism evolution in a phylogenetic framework and demonstrate that both processes contribute to dimorphic wing patterns in the butterfly genera Bicyclus and Junonia. In some lineages, eyespots and bands arise in a single sex, whereas in other lineages they appear in both sexes but are then lost in one of the sexes. In addition, lineages displaying sexual dimorphism were more likely to become sexually monomorphic than they were to remain dimorphic. This derived monomorphism was either owing to a loss of the ornament ('drab monomorphism') or owing to a gain of the same ornament by the opposite sex ('mutual ornamentation'). Our results demonstrate the necessity of a plurality in theories explaining the evolution of sexual dimorphism within and across taxa. The origins and evolutionary fate of sexual dimorphism are probably influenced by underlying genetic architecture responsible for sex-limited expression and the degree of intralocus sexual conflict. Future comparative and developmental work on sexual dimorphism within and among taxa will provide a better understanding of the biases and constraints governing the evolution of animal sexual dimorphism.     

On the general theory of the origins of retroviruses

Background  

The order retroviridae comprises viruses based on ribonucleic acids (RNA). Some, such as HIV and HTLV, are human pathogens. Newly emerged human retroviruses have zoonotic origins. As far as has been established, both repeated infections (themselves possibly responsible for the evolution of viral mutations (Vm) and host adaptability (Ha)); along with interplay between inhibitors and promoters of cell tropism, are needed to effect retroviral cross-species transmissions. However, the exact modus operadi of intertwine between these factors at molecular level remains to be established. Knowledge of such intertwine could lead to a better understanding of retrovirology and possibly other infectious processes. This study was conducted to derive the mathematical equation of a general theory of the origins of retroviruses.     

On the origins of novelty in development and evolution

The origin of novel traits is what draws many to evolutionary biology, yet our understanding of the mechanisms that underlie the genesis of novelty remains limited. Here I review definitions of novelty including its relationship to homology. I then discuss how ontogenetic perspectives may allow us to move beyond current roadblocks in our understanding of the mechanics of innovation. Specifically, I explore the roles of canalization, plasticity and threshold responses during development in generating a reservoir of cryptic genetic variation free to drift and accumulate in natural populations. Environmental or genetic perturbations that exceed the buffering capacity of development can then release this variation, and, through evolution by genetic accommodation, result in rapid diversification, recurrence of lost phenotypes as well as the origins of novel features. I conclude that, in our quest to understand the nature of innovation, the nature of development deserves to take center stage.