The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio(Asteraceae)

Ecological speciation, driven by adaptation to contrasting environments, provides an attractive opportunity to study the formation of distinct species, and the role of selection and genomic divergence in this process. Here, we focus on a particularly clear-cut case of ecological speciation to reveal the genomic bases of reproductive isolation and morphological differences between closely related Senecio species, whose recent divergence within the last ~200 000 years was likely driven by the uplift of Mt. Etna (Sicily). These species form a hybrid zone, yet remain morphologically and ecologically distinct, despite active gene exchange. Here, we report a high-density genetic map of the Senecio genome and map hybrid breakdown to one large and several small quantitative trait loci (QTL). Loci under diversifying selection cluster in three 5 cM regions which are characterized by a significant increase in relative (FST), but not absolute (dXY), interspecific differentiation. They also correspond to some of the regions of greatest marker density, possibly corresponding to ‘cold-spots’ of recombination, such as centromeres or chromosomal inversions. Morphological QTL for leaf and floral traits overlap these clusters. We also detected three genomic regions with significant transmission ratio distortion (TRD), possibly indicating accumulation of intrinsic genetic incompatibilities between these recently diverged species. One of the TRD regions overlapped with a cluster of high species differentiation, and another overlaps the large QTL for hybrid breakdown, indicating that divergence of these species may have occurred due to a complex interplay of ecological divergence and accumulation of intrinsic genetic incompatibilities

Biodegradation of Oil Hydrocarbons by Soil Microflora Activated with Photoluminescence Films

Stimulating effect of polyethylene photoluminescence films on the growth of autochthonous microflora population in oil-polluted soils has been determined under the laboratory conditions, where oil concentration in the soil was 50 g/kg. The increase in number of basic groups of microflora was accompanied with the increased activity of the enzymes, which catalyzed oxidizing processes. At the end of the experiment, on the 45-th day, oil content decreased to 15 g/kg. The analysis of the residual hydrocarbons by IR-spectroscopy has revealed absorption bands in the regions of 1710 cm–1 and 1600 cm–1. At the same time spectral coefficients С1, С2, А1 and А2 increased 1.5-3 times, while С3 and А3 decreased 1.5-2.5 times indicating oxidation processes of oil hydrocarbons. Chromatographic analysis proved the intensity of hydrocarbon biodegradation. Hydrocarbons С11-С14 completely eliminated in the test samples and the concentration of hydrocarbons with a high molecular weight decreased by 70-80%. At the same time hydrocarbon biodegradation index, determined as the ratio of the sum of isoprenoids (pristine + phytane) to the sum of n-alkanes (С17 + С18), increased 5-6 times due to the use of photoluminescence films

Seasonal changes in milk quality indicators jersey cows

The article presents the results of studies of milk quality indicators: the mass fraction of fat, the mass fraction of protein and the number of somatic cells in the Jersey breed in the Stavropol Territory in 2022-2023. In the autumn period, the indicators of the mass fraction of fat and protein were higher compared to other seasons and equal to 6.08% and 4.66%, respectively. The number of somatic cells was also increased in the autumn and spring periods of 140 and 146 thousand units/ml, respectively. A significant negative correlation of the mass fraction of protein and average daily productivity to the number of somatic cells r = -0.21 and -0.12 was established. And a significant positive correlation between the mass fraction of fat and the level of somatic cells r = 0.52

Evolution of genome size in Hawaiian endemic genus Schiedea (Caryophyllaceae)

Genome sizes may vary by orders of magnitude among relatively closely related species. Gene and genome duplications and movements of transposable elements (TEs) can quickly inflate genome sizes. Whole genome duplications (polyploidization) may be an important source of evolutionary innovation and many fast evolving island genera are known or assumed to be polyploids. Our main aim is to shed light on the question of how genome size evolved within a rapidly diversifying island lineage. We report the estimates of DNA content for 27 species of the Hawaiian endemic plant genus Schiedea and its widespread sister genus Honckenya (Caryophyllaceae: Alsinoideae). Unexpectedly, genomes of Schiedea species appeared to be relatively compact (1.41 to 3.74 pg/cell), compared to Honckenya (8.57 to 10.66 pg/cell). Interestingly, Schiedea species from younger islands tended to have larger genomes than species from older islands, which may be explained by activation of TE transpositions in small populations after colonization events that resulted in the formation of new species on younger islands. To test whether the Schiedea genome has undergone recent polyploidization events we measured divergence between 62 pairs of paralogous genes in S. globosa. The distribution of divergence values was unimodal with a mode of 7%, supporting a single polyploidization event. Dating this event using Schiedea/Honckenya divergence (2%) and Schiedea/Silene divergence (11%) we estimate that it might have occurred in the ancestor of the genera Schiedea and Honckenya, but after the split between the subfamilies Alsinoideae and Silenoideae

Gene flow and species cohesion following the spread of Schiedea globosa (Caryophyllaceae) across the Hawaiian Islands

Island radiations are often regarded as natural laboratories that allow us to study evolution in action. The genus Schiedea (Caryophyllaceae) is one of the largest radiations of angiosperms in the Hawaiian Islands, and Schiedea globosa is one of the few species in the genus to be found on more than one of the main islands. DNA sequences from nineteen nuclear and three chloroplast regions show a pattern of colonization from older to younger islands (west to east), with a concomitant decrease in genetic diversity eastwards (π = 0.53% for O'ahu, 0.43% for Moloka'i and 0.36% for Maui). While polymorphisms in the maternally inherited chloroplast have become fixed on different islands (FST = 0.804), significant gene flow between islands is inferred for the nuclear genome (FST = 0.270). This gene flow appears to be uneven, with most gene flow outwards from the central island. The extent of inter-island gene flow through wind pollination was assessed in an isolation-migration framework; the inferred rate, c. 1 migrant per generation, may be sufficient to prevent divergence of S. globosa populations and ensure cohesion of the species following the colonization of new islands

Molecular adaptation during a rapid adaptive radiation

Explosive adaptive radiations on islands remain one of the most puzzling evolutionary phenomena and the evolutionary genetic processes behind such radiations remain unclear. Rapid morphological and ecological evolution during island radiations suggests that many genes may be under fairly strong selection, although this remains untested. Here, we report that during a rapid recent diversification in the Hawaiian endemic plant genus Schiedea (Caryophyllaceae), 5 in 36 studied genes evolved under positive selection. Positively selected genes are involved in defence mechanisms, photosynthesis, and reproduction. Comparison with eight mainland plant groups demonstrates both the relaxation of purifying selection and more widespread positive selection in Hawaiian Schiedea. This provides compelling evidence that adaptive evolution of protein-coding genes may play a significant role during island adaptive radiations

Seasonal changes in milk quality indicators jersey cows

The article presents the results of studies of milk quality indicators: the mass fraction of fat, the mass fraction of protein and the number of somatic cells in the Jersey breed in the Stavropol Territory in 2022-2023. In the autumn period, the indicators of the mass fraction of fat and protein were higher compared to other seasons and equal to 6.08% and 4.66%, respectively. The number of somatic cells was also increased in the autumn and spring periods of 140 and 146 thousand units/ml, respectively. A significant negative correlation of the mass fraction of protein and average daily productivity to the number of somatic cells r = -0.21 and -0.12 was established. And a significant positive correlation between the mass fraction of fat and the level of somatic cells r = 0.52

Numerical issues in mold filling simulations of liquid composites processing

Rubisco, the most abundant enzyme on the Earth and responsible for all photosynthetic carbon fixation, is often thought of as a highly conserved and sluggish enzyme. Yet, different algal Rubiscos demonstrate a range of kinetic properties hinting at a history of evolution and adaptation. Here, we show that algal Rubisco has indeed evolved adaptively during ancient and distinct geological periods. Using DNA sequences of extant marine algae of the red and Chromista lineage, we define positive selection within the large subunit of Rubisco, encoded by rbcL, to occur basal to the radiation of modern marine groups. This signal of positive selection appears to be responding to changing intracellular concentrations of carbon dioxide (CO2) triggered by physiological adaptations to declining atmospheric CO2. Within the ecologically important Haptophyta (including coccolithophores) and Bacillariophyta (diatoms), positive selection occurred consistently during periods of falling Phanerozoic CO2 and suggests emergence of carbon-concentrating mechanisms. During the Proterozoic, a strong signal of positive selection after secondary endosymbiosis occurs at the origin of the Chromista lineage (approx. 1.1 Ga), with further positive selection events until 0.41 Ga, implying a significant and continuous decrease in atmospheric CO2 encompassing the Cryogenian Snowball Earth events. We surmise that positive selection in Rubisco has been caused by declines in atmospheric CO2 and hence acts as a proxy for ancient atmospheric CO2