Expression of visual and nonvisual opsins in American chameleon

AbstractWe previously characterized five visual opsin genes of American chameleon (Anolis carolinensis). Here we report its nonvisual opsin gene orthologous to the chicken pineal gland-specific opsin (P-opsin) gene. In the pure-cone American chameleon retina, all visual opsins including rod opsin are expressed. In both pineal and parietal eye, three visual opsins as well as P-opsin are expressed. Although opsins are detected in the pineal glands of a wide variety of vertebrates, Southern analysis suggests that the P-opsin gene is used mainly by birds and reptiles

A genetically explicit model of speciation by sensory drive within a continuous population in aquatic environments

<p>Abstract</p> <p>Background</p> <p>The sensory drive hypothesis predicts that divergent sensory adaptation in different habitats may lead to premating isolation upon secondary contact of populations. Speciation by sensory drive has traditionally been treated as a special case of speciation as a byproduct of adaptation to divergent environments in geographically isolated populations. However, if habitats are heterogeneous, local adaptation in the sensory systems may cause the emergence of reproductively isolated species from a single unstructured population. In polychromatic fishes, visual sensitivity might become adapted to local ambient light regimes and the sensitivity might influence female preferences for male nuptial color. In this paper, we investigate the possibility of speciation by sensory drive as a byproduct of divergent visual adaptation within a single initially unstructured population. We use models based on explicit genetic mechanisms for color vision and nuptial coloration.</p> <p>Results</p> <p>We show that in simulations in which the adaptive evolution of visual pigments and color perception are explicitly modeled, sensory drive can promote speciation along a short selection gradient within a continuous habitat and population. We assumed that color perception evolves to adapt to the modal light environment that individuals experience and that females prefer to mate with males whose nuptial color they are most sensitive to. In our simulations color perception depends on the absorption spectra of an individual's visual pigments. Speciation occurred most frequently when the steepness of the environmental light gradient was intermediate and dispersal distance of offspring was relatively small. In addition, our results predict that mutations that cause large shifts in the wavelength of peak absorption promote speciation, whereas we did not observe speciation when peak absorption evolved by stepwise mutations with small effect.</p> <p>Conclusion</p> <p>The results suggest that speciation can occur where environmental gradients create divergent selection on sensory modalities that are used in mate choice. Evidence for such gradients exists from several animal groups, and from freshwater and marine fishes in particular. The probability of speciation in a continuous population under such conditions may then critically depend on the genetic architecture of perceptual adaptation and female mate choice.</p

Lateral Flow Deformation Evaluation of Ground-Structure System under Various Cyclic Loading Conditions

In order to clarify the mechanical behaviors of sand grounds induced by various loadings including sea wave forces, traffic vibrations and earthquake etc., a series of model tests were carried out on model structure-ground system by using, the two-dimensional plane strain soil box apparatus. It was found that; (1) the lateral flow behavior of ground depends strongly on settlement performance of a structure, (2) the bearing capacity of ground may be evaluated by a failure envelope which is depicted in M-V-H plane irrespective of the difference in loading conditions and (3) the stability of sand ground-structure system can be assessed on the basis of a parameter Vσ/ Vρ which quantifies the lateral flow deformation

Medaka: a promising model animal for comparative population genomics

<p>Abstract</p> <p>Background</p> <p>Within-species genome diversity has been best studied in humans. The international HapMap project has revealed a tremendous amount of single-nucleotide polymorphisms (SNPs) among humans, many of which show signals of positive selection during human evolution. In most of the cases, however, functional differences between the alleles remain experimentally unverified due to the inherent difficulty of human genetic studies. It would therefore be highly useful to have a vertebrate model with the following characteristics: (1) high within-species genetic diversity, (2) a variety of gene-manipulation protocols already developed, and (3) a completely sequenced genome. Medaka (<it>Oryzias latipes</it>) and its congeneric species, tiny fresh-water teleosts distributed broadly in East and Southeast Asia, meet these criteria.</p> <p>Findings</p> <p>Using <it>Oryzias </it>species from 27 local populations, we conducted a simple screening of nonsynonymous SNPs for 11 genes with apparent orthology between medaka and humans. We found medaka SNPs for which the same sites in human orthologs are known to be highly differentiated among the HapMap populations. Importantly, some of these SNPs show signals of positive selection.</p> <p>Conclusion</p> <p>These results indicate that medaka is a promising model system for comparative population genomics exploring the functional and adaptive significance of allelic differentiations.</p

Fruit scent and observer colour vision shape food-selection strategies in wild capuchin monkeys

The senses play critical roles in helping animals evaluate foods, including fruits that can change both in colour and scent during ripening to attract frugivores. Although numerous studies have assessed the impact of colour on fruit selection, comparatively little is known about fruit scent and how olfactory and visual data are integrated during foraging. We combine 25 months of behavioural data on 75 wild, white-faced capuchins (Cebus imitator) with measurements of fruit colours and scents from 18 dietary plant species. We show that frequency of fruit-directed olfactory behaviour is positively correlated with increases in the volume of fruit odours produced during ripening. Monkeys with red-green colour blindness sniffed fruits more often, indicating that increased reliance on olfaction is a behavioural strategy that mitigates decreased capacity to detect red-green colour contrast. These results demonstrate a complex interaction among fruit traits, sensory capacities and foraging strategies, which help explain variation in primate behaviour.https://www.nature.com/articles/s41467-019-10250-9Published versio