Ontogenes and the genetics of intraspecific similarity

The experiments by Gregor Mendel, which formed the background for genetics, were performed with the characters of intraspecific difference (alternative characters). Mendelian protein-coding genes are responsible for these characters. Until recently, these genes were regarded as the only and main hereditary factors responsible for ontogenesis and phylogenesis. The review outlines the information about another category of biological characters (the characters of intraspecific similarity) and, correspondingly, of a special category of genes responsible for these characters (ontogenes). The study into mutations of ontogenes in drosophila experiments suggests that (1) ontogenes control the construction of cell ensembles and trigger protein-coding genes in cells; (2) the program of individual development is encoded in ontogenes and “edited” in germline cells; (3) ontogenes fulfill a regulatory function without any contacts and chemical intermediaries, which suggests a kind of biophysical activity; and (4) two categories of cells—stem cells and terminally differentiated cells—correspond to these two categories of genes. Ontogenes are active in stem cells and protein-coding genes, in terminally differentiated cells.

Trait responses of Peninsular Malaysian dung beetles (Scarabaeidae: Scarabaeinae) to the loss of megafauna dung

The extinction of megafauna may lead to the trophic collapse of ecosystems that depend on the dung that they produce. Some dung beetle species may undergo phenotypic changes in response to altered resource availability. The pronotal width of dung beetles is a trait that can be used as a proxy measure for the amount of dung provisioned during the larval stage. In this study conducted in Peninsular Malaysia, we compare the intraspecific difference in pronotal widths of dung beetles in forests with and without megafauna. Beetles were collected using burrowing interception traps baited with elephant dung. Six species with a minimum sample size of 55 beetles per species were used. Pronotum widths were compared using Bayesian estimation (BEST). There was no credible difference between intraspecific pronotal widths of four species, but credible differences between the mean parameters of two species, Liatongus femoratus and Oniticellus tessellatus. Both these species belong to genera that have a close association with megafauna, while the other are believed to be generalists. This may indicate that species that depend on megafauna dung as a breeding resource undergo a phenotypic change following the loss of their preferred dung type. Phenotypic changes appear to be a pathway which allows species to survive the initial trophic collapse of an ecosystem.

Intraspecific difference among herbivore lineages and their host-plant specialization drive the strength of trophic cascades

Trophic cascades—the indirect effect of predators on non-adjacent lower trophic levels—are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underlying ecological networks. Here we experimentally investigated how intraspecific difference among herbivore lineages specialized on different host plants influences the strength of trophic cascade in a terrestrial tritrophic system. We found that the occurrence and strength of the trophic cascade are strongly influenced by herbivores’ lineage and host-plant specialization but are not associated with density-dependent effects mediated by the growth rate of herbivore populations. Our findings stress the importance of intraspecific heterogeneities and evolutionary specialization as drivers of the strength of trophic cascades and underline that intraspecific variation should not be overlooked to decipher the joint influence of evolutionary and ecological factors on the functioning of multi-trophic interactions.

Molecular data infers the involvement of a marine aurantiactinomyxon in the life cycle of the myxosporean parasite Paramyxidium giardi (Cnidaria, Myxozoa)

An aurantiactinomyxon type is described from the marine naidid Tubificoides pseudogaster (Dahl, 1960), collected from the lower estuary of a Northern Portuguese River. This type constitutes the first of its collective group to be reported from Portugal, and only the fourth described from a marine oligochaete worldwide. Extensive morphological comparisons of new aurantiactinomyxon isolates to all known types without available molecular data are proposed to be unnecessary, given the artificiality of the usage of morphological criteria for actinosporean differentiation and the apparent strict host specificity of the group. Recognition of naidid oligochaetes as the hosts of choice for marine types of aurantiactinomyxon and other collective groups, suggests that the family Naididae played a preponderant role in the myxosporean colonization of estuarine communities. Molecular analyses of the type in study further infer its involvement in the life cycle of Paramyxidium giardi (Cépède, 1906) Freeman and Kristmundsson, 2018, a species that infects the kidney of European eel Anguilla anguilla (Linnaeus, 1758) and that has been reported globally, including from Portuguese waters. The low intraspecific difference registered in relation to Icelandic isolates of P. giardi (0.6%) is hypothesized to result from the emergence of genotypically different subspecies due to geographic isolation.

Genetic Analysis of Inonotus Obliquus Strains by RAPD

Genetic Analysis ofInonotus ObliquusStrains by RAPDRAPD profiling of eightInonotus obliquusstrains isolated from sclerotia collected from different areas of China was conducted to determine the genetic variability within this important medicinal fungus and to better define relationships between the genotype and geographical origins of isolation. Twelve 10-mer primers generated a total of 167 stable and reproducible DNA fragments, of which 101 (60.5%) were polymorphic. DNA fingerprints revealed genetic diversity among the strains tested, but there was the little intraspecific difference between the fingerprints of individual strains. A phenogram constructed based on UPGMA analysis of genetic distances calculated from RAPD fragment data identified three distinct groupings: (1) BCX01 and BCX02, (2) JL01, JL02, JL03, JL04 and JL05, (3) HLJ01. Our data confirm that the genetic variability among different strains may be a useful ancillary tool for identifyingl. obliquussclerotia of different geographical origins.

L'induction chez Ceratocystis de fructifications de types Graphium et Leptographium par des acides gras insaturés

The unsaturated fatty acids oleic, linoleic, and linolenic induce the formation of the imperfect state of fructification of the Graphium type (coremia) with Ceratocystis ulmi and C. piceae and the Leptographium type with C. penicillata. Intraspecific difference between several strains of C. ulmi show that linoleic acid is the best inducer with an optimal concentration from 0.05 to 0.20 g/ml of methanol between the 10th and 25th day of culture. Linoleic and linolenic acid extend the capacity of sporulation of C. penicillata, conserving the strains capability of differentiation of Leptographium structures when ordinarily only the natural substrate can reinduce it. Ceratocystis dryocoetidis cultivated in the same conditions remains insensible to the lipid treatments.

Studies on lichen-dominated systems. XVI. Comparative patterns of net CO2 exchange in Cetraria nivalis and Alectoria ochroleuca collected from a raised-beach ridge

Seasonal patterns of net photosynthesis in Cetraria nivalis that was collected from the top and bottom positions of a raised-beach ridge were examined in relation to those for Alectoria ochroleuca from the same site. While seasonal acclimation is pronounced in C. nivalis to an extent equal to that found in A. ochroleuca, C. nivalis showed significant intraspecific difference in these patterns. Cetraria nivalis that was collected from the bottom position of the beach ridge is more active metabolically than the ridge-top collections. Cetraria nivalis is most abundant on the lower slopes of these ridges. A comparison of the physiological data matrices for both ridge-top and ridge-bottom collections of A. ochroleuca and C. nivalis partly explains the patterns of species distribution that are observed in the field.