Relationships between the allozyme and phenotypic diversities of Picea ajanensis populations

The structures of Picea ajanensis populations were compared based on allozyme analysis of vegetative buds and morphometric analysis of generative organs. Six cenopopulations of P. ajanensis were investigated in areas with various levels of volcanic impact in the Kamchatka Peninsula. The genetic structures of spruce populations and phenotypes were determined by analysis of ten enzyme systems (PGM, GOT, HK, LAP, MDH, SKDH, IDH, GDH, PGI and SOD). Phenotypic variability of spruce populations was estimated based on the composition of morphotypes that were identified by using geometric morphometrics of cone-scale shapes. Pairwise comparison of samples of cones from 170 trees from six populations revealed 12 morphotypes differing in the shape of cone scales. Comparative assessment of variability and similarity of populations was carried out based on the frequency of occurrence of phenotypes and frequency of alleles of polymorphic loci. Correlations of the genetic and phenotypic distance matrices between different phenotypes were revealed. This observation was consistent with the genetic determination of the shape of cone scales in spruce. Genetic differences between the morphotypes with regard to nine polymorphic loci (Got-2, Skdh-1, Idh-2, Pgm-2, Mdh-1, Mdh-3, Pgm- 1, Pgi-2, and Hk) were not significant. Statistically significant differences between the morphotypes were revealed for two loci: Pgm-2 and Mdh-1. Differences in the genetic diversity of spruce populations generally corresponded to differences in their phenotypic diversity. The high levels of genetic and phenotypic diversity characterized a stable population structure of spruce in the area of weak volcanic influence. Changes in the genetic structure and low levels of the phenotypic diversity of spruce were observed under catastrophic volcanic impact

New constraints on atmospheric CO2 concentration for the Phanerozoic

Earth's atmospheric CO2 concentration (ca) for the Phanerozoic Eon is estimated from proxies and geochemical carbon cycle models. Most estimates come with large, sometimes unbounded uncertainty. Here, we calculate tightly constrained estimates of ca using a universal equation for leaf gas exchange, with key variables obtained directly from the carbon isotope composition and stomatal anatomy of fossil leaves. Our new estimates, validated against ice cores and direct measurements of ca, are less than 1000 ppm for most of the Phanerozoic, from the Devonian to the present, coincident with the appearance and global proliferation of forests. Uncertainties, obtained from Monte Carlo simulations, are typically less than for ca estimates from other approaches. These results provide critical new empirical support for the emerging view that large (~2000-3000 ppm), long-term swings in ca do not characterize the post-Devonian and that Earth's long-term climate sensitivity to ca is greater than originally thought. Key Points A novel CO2 proxy calculates past atmospheric CO2 with improved certainty CO2 is unlikely to have exceeded ~1000 ppm for extended periods post Devonian Earth's long-term climate sensitivity to CO2 is greater than originally thought

Recovery of dialysis patients with COVID-19 : health outcomes 3 months after diagnosis in ERACODA

Background. Coronavirus disease 2019 (COVID-19)-related short-term mortality is high in dialysis patients, but longer-term outcomes are largely unknown. We therefore assessed patient recovery in a large cohort of dialysis patients 3 months after their COVID-19 diagnosis. Methods. We analyzed data on dialysis patients diagnosed with COVID-19 from 1 February 2020 to 31 March 2021 from the European Renal Association COVID-19 Database (ERACODA). The outcomes studied were patient survival, residence and functional and mental health status (estimated by their treating physician) 3 months after COVID-19 diagnosis. Complete follow-up data were available for 854 surviving patients. Patient characteristics associated with recovery were analyzed using logistic regression. Results. In 2449 hemodialysis patients (mean ± SD age 67.5 ± 14.4 years, 62% male), survival probabilities at 3 months after COVID-19 diagnosis were 90% for nonhospitalized patients (n = 1087), 73% for patients admitted to the hospital but not to an intensive care unit (ICU) (n = 1165) and 40% for those admitted to an ICU (n = 197). Patient survival hardly decreased between 28 days and 3 months after COVID-19 diagnosis. At 3 months, 87% functioned at their pre-existent functional and 94% at their pre-existent mental level. Only few of the surviving patients were still admitted to the hospital (0.8-6.3%) or a nursing home (∼5%). A higher age and frailty score at presentation and ICU admission were associated with worse functional outcome. Conclusions. Mortality between 28 days and 3 months after COVID-19 diagnosis was low and the majority of patients who survived COVID-19 recovered to their pre-existent functional and mental health level at 3 months after diagnosis

Automatic identification of variables in epidemiological datasets using logic regression

textabstractBackground: For an individual participant data (IPD) meta-analysis, multiple datasets must be transformed in a consistent format, e.g. using uniform variable names. When large numbers of datasets have to be processed, this can be a time-consuming and error-prone task. Automated or semi-automated identification of variables can help to reduce the workload and improve the data quality. For semi-automation high sensitivity in the recognition of matching variables is particularly important, because it allows creating software which for a target variable presents a choice of source variables, from which a user can choose the matching one, with only low risk of having missed a correct source variable. Methods: For each variable in a set of target variables, a number of simple rules were manually created. With logic regression, an optimal Boolean combination of these rules was searched for every target variable, using a random subset of a large database of epidemiological and clinical cohort data (construction subset). In a second subset of this database (validation subset), this optimal combination rules were validated. Results: In the construction sample, 41 target variables were allocated on average with a positive predictive value (PPV) of 34%, and a negative predictive value (NPV) of 95%. In the validation sample, PPV was 33%, whereas NPV remained at 94%. In the construction sample, PPV was 50% or less in 63% of all variables, in the validation sample in 71% of all variables. Conclusions: We demonstrated that the application of logic regression in a complex data management task in large epidemiological IPD meta-analyses is feasible. However, the performance of the algorithm is poor, which may require backup strategies

Variability of allozyme locus and inbreeding level in the age groups of southern-taiga and forest-steppe pine populations of the Central Siberia

The results of the study of isozymes variability of Scots pine populations growing in the southern taiga and forest-steppe of Central Siberia are presented. For the analysis 16 polymorphic loci were used. Two age groups (adult trees and undergrowth) are compared for the main indicators of genetic variation. The greatest deficiency of heterozygotes and a statistically significant level of inbreeding was found in the progeny of a small isolated population most disturbed by cuttings from the vicinity of the city of Achinsk. This population was distinguished by the high genetic distance of Nei (1972) between compared generations of trees, comparable to the distances between geographically remote populations. In the majority of other population samples exposed to lower anthropogenic pressure, the average level of heterozygosity was noted, or the observed heterozygosity was higher than expected in two age groups of trees, and deviations from the equilibrium state were found for individual loci, which, as a rule, do not coincide in adult trees and sprouts. The results of the study show that the genetic structure of the populations of Scotch pine Pinus sylvestris L. is quite resistant to the average level of anthropogenic (recreational) load. But the greater negative effect of using forest is associated with an increased risk of loss of allelic diversity (in 3 populations from 8 to 10.0–14.5 %) and, accordingly, the adaptive genetic polymorphism of populations. The necessity of using more sensitive than allozyme markers of genetic polymorphism of species populations (DNA markers of the nuclear and, especially, of the cytoplasmic genomes) in order to detect more subtle disturbances and initial stages of negative processes for the resumption of the gene pool of the processes was noted

Differentiation of Scots pine populations in the belt pine forests of Altai Krai discovered with markers of various nature

In the territory of steppe zone of Ob’-Irtysh interfluve it was studied the differentiation of scots pine populations of belt forests with use of allozyme’s, phene’s and morphometric markers. Here allocated 2 forest-seed zoning and border between them practically coincides with border between Siberian and Kulunda pine subspecies on L. F. Pravdin’s classification. Allozyme’s analysis didn’t reveal significant differentiation of stands, except for rare differences between some of them and a slight trend for decrease in effective number of alleles in the more southern populations. The analysis of a molecular variance (AMOVA) also shows absence of differentiation of populations from different forest-seed zoning. Differentiation of populations by using phenes (coloring of seeds, type of cone’s apophysis) and high-inherited morphometric characters (index form of cones and weight of 1000 seeds) was more effective at comparing populations on both levels – between and within forest-seed zoning. It allowed revealing of reliable distinctions between populations in almost 82 % of cases of total number of the compared couples of populations, thus extent of differentiation using the allozyme’s markers is almost three times lower. The assessment of population structure of pine in tape forest of Altai region, which is carried out with application of a complex of markers, indicates between-populations heterogeneity in this part of area. The received results confirm the expediency of complex researches of population structure of forest-forming species and the necessity of more precise definition of forest-seed zoning of a scots pine in the studied territory

Stage-by-Stage Certification of Trees in Plantations of Scots Pine Genetic Breeding Complex

In Altai territory in Scots pine (Pinus sylvestris L.) clonal plantations, that include nearly 1.5 thousand trees of 118 clones, the stage-by-stage certification of trees was carried out. Certification process included 3 stages: 1) forestry stage (preliminary), 2) phenetic stage (basic), 3) genetical stage (précising). Accuracy of phenetic certification was 97.1 %. The final stage of certification was carried out taking into account of revealed «phenetic clusters» within of clones. One-ramet and many-ramets («mixed») samples were compared within clusters and these must show identical results if all ramets are truly marked. The stage-by-stage certification method allows less expensive molecular genetics testing in some cases

The Use of Genetic Markers of Various Types for Evaluation of Intraspecific Differentiation Level of the Siberian Spruce

On the basis of the analysis of variability of isoenzyme loci and microsatellite loci of nuclear and chloroplast DNA the data were obtained about the degree of differentiation of a number populations of Siberian spruce (Picea obovata Ledeb.), including isolated populations located on the island of Olkhon, in the reserve Bogd-Uul (Mongolia) and on the south of the Magadan region. It was shown that the combined use of various types of genetic markers gives an opportunity to get more complete and objective information about a genetic diversity and intraspecific differentiation of this widespread in Siberia species