Registration and modeling of introgressive processes in mixed and isolated populations of Elymus gmelinii and E. pendulinus (Poaceae: Triticeae) in the southern Primorye Territory (Russia)

The Saxifraga rivularis complex in Svalbard: Molecules, ploidy and morphology

Genetic fidelity assessment of wild and tissue cultured regenerants of a threatened orchid, Cymbidium aloifolium using molecular markers

Genetic variation in a species enhances the capability of organism to adapt to changing environment and is necessary for survival of the species. Genetic variation arises between individuals leading to differentiation at the level of population, species and higher order taxonomic groups. The genetic diversity data has varied application in research on evolution, conservation and management of natural resources and genetic improvement programmes, etc. Development of Molecular genetic markers has powerful ability to detect genetic studies of individuals, populations or species. These molecular markers combined with new statistical developments have revolutionized the analytical power, necessary to explore the genetic diversity. Molecular markers and their statistical analysis revolutionized the analytical power, necessary to explore the genetic diversity. Various molecular markers, protein or DNA (mt-DNA or nuclear DNA such as microsatellites, SNP or RAPD) are now being used in fisheries and aquaculture. These markers provide various scientific observations which have importance in aquaculture practice recently such as: 1) Species Identification 2) Genetic variation and population structure study in natural populations 3) Comparison between wild and hatchery populations 4) Assessment of demographic bottleneck in natural population 5) Propagation assisted rehabilitation programmes. In this review article, we have concentrated on the basics of molecular genetics, overview of commonly used markers and their application along with their limitations (major classes of markers) in fisheries and aquaculture studies.

Habitat fragmentation, i.e., fragment size and isolation, can differentially alter patterns of neutral and quantitative genetic variation, fitness and phenotypic plasticity of plant populations, but their effects have rarely been tested simultaneously. We assessed the combined effects of size and connectivity on these aspects of genetic and phenotypic variation in populations of Centaurea hyssopifolia, a narrow endemic gypsophile that previously showed performance differences associated with fragmentation. We grew 111 maternal families sampled from 10 populations that differed in their fragment size and connectivity in a common garden, and characterized quantitative genetic variation, phenotypic plasticity to drought for key functional traits, and plant survival, as a measure of population fitness. We also assessed neutral genetic variation within and among populations using eight microsatellite markers. Although C. hyssopifolia is a narrow endemic gypsophile, we found substantial neutral genetic variation and quantitative variation for key functional traits. The partition of genetic variance indicated that a higher proportion of variation was found within populations, which is also consistent with low population differentiation in molecular markers, functional traits and their plasticity. This, combined with the generally small effect of habitat fragmentation suggests that gene flow among populations is not restricted, despite large differences in fragment size and isolation. Importantly, population’s similarities in genetic variation and plasticity did not reflect the lower survival observed in isolated populations. Overall, our results indicate that, although the species consists of genetically variable populations able to express functional plasticity, such aspects of adaptive potential may not always reflect populations’ survival. Given the differential effects of habitat connectivity on functional traits, genetic variation and fitness, our study highlights the need to shift the focus of fragmentation studies to the mechanisms that regulate connectivity effects, and call for caution on the use of genetic variation and plasticity to forecast population performance.

Polyurethane-coated fabrics are widely employed as tarpaulin materials. However, due to the long duration and large space requirements of natural exposure tests, studies on fabric degradation remain scarce. To systematically investigate the natural aging patterns and mechanisms of polyurethane-coated fabrics, this study conducted 24-month natural aging tests in three representative regions: Xishuangbanna (tropical monsoon climate), Xiamen (subtropical maritime monsoon climate), and Jinan (temperate monsoon climate). Changes in appearance, mechanical properties, surface morphology, elemental composition, and microstructure were thoroughly analyzed. The results indicated that gloss decreased by over 60%, the color difference exceeded 5.8, and tear strength was reduced by more than 50%. SEM, ATR-FTIR, and XPS analyses revealed that hydrolysis and oxidation occurred in the coating, leading to coating thinning, fiber exposure, and even damage. In Xishuangbanna, high temperature, high humidity, and strong solar radiation are responsible for the most severe degradation of fabrics. High temperature, humidity, and salt fog synergistically accelerated the aging process. In Jinan, significant thermal strain contributed to deterioration, and fabrics exhibited the mildest degradation. This multi-region natural exposure study realistically simulates in-service aging behavior, providing important validation for accelerated laboratory aging methods, product reliability improvement, and service-life modeling.

Trees and shrubs belonging to the Betula L. genus seem to represent one of the most confused interspecific relationships, and hybridization is considered to be one of the main factors responsible for the substantial genetic and morphological variation of birches. In the present investigation, the internal transcribed spacer ITS1 and ITS2 regions of nuclear ribosomal DNA, nuclear alcohol dehydrogenase (ADH) gene sequences and amplified fragment length polymorphisms (AFLPs) as well as the Atkinson discriminant function (ADF) of leaf morphology were used to verify hypotheses concerning the origin of the dark barked Betula obscura and B. pendula var. carelica with the patterned wood. Both plants were considered by different authors to be distinct species, intraspecific forms of common B. pendula or B. pubescens, or hybrid taxa between B. pendula and B. pubescens. In the phylogenetic trees, the ITS and ADH gene sequences of both B. obscura and B. pendula var. carelica clustered with those of B. pendula, whereas B. pubescens trees were somewhat distinct. In turn, the AFLPs revealed genetic similarity of B. pendula var. carelica to both frequent species, whereas B. obscura was clearly distinct from other birches. Values of the ADF indices of the rare birches were typical for B. pendula. In the light of the results obtained, we imply that B. obscura and B. pendula var. carelica represent an intraspecific variation of B. pendula, they are neither intraspecific taxa of B. pubescens nor hybrid species between the common birches. Different grouping of B. obscura in the AFLPs and DNA sequences analyses is likely a result of an unreliable phylogenetic signal of the former molecular markers.

Genetic variation in a species enhances the capability of organism to adapt to changing environment and is necessary for survival of the species. Genetic variation arises between individuals leading to differentiation at the level of population, species and higher order taxonomic groups. The genetic diversity data has varied application in research on evolution, conservation and management of natural resources and genetic improvement programmes, etc. Development of Molecular genetic markers has powerful ability to detect genetic studies of individuals, populations or species. These molecular markers combined with new statistical developments have revolutionized the analytical power, necessary to explore the genetic diversity. Molecular markers and their statistical analysis revolutionized the analytical power, necessary to explore the genetic diversity. Various molecular markers, protein or DNA (mt-DNA or nuclear DNA such as microsatellites, SNP or RAPD) are now being used in fisheries and aquaculture. These markers provide various scientific observations which have importance in aquaculture practice recently such as: 1) Species Identification 2) Genetic variation and population structure study in natural populations 3) Comparison between wild and hatchery populations 4) Assessment of demographic bottleneck in natural population 5) Propagation assisted rehabilitation programmes. In this review article, we have concentrated on the basics of molecular genetics, overview of commonly used markers and their application along with their limitations (major classes of markers) in fisheries and aquaculture studies.

Performance evaluation of induced mutant lines of black gram (Vigna mungo (L.) Hepper)

Genetic population divergence: markers and traits

Monitoring the genetic diversity of small populations is important with respect to conserving rare and valuable chicken breeds, as well as discovery and innovation in germplasm research and application. Restriction fragment length polymorphisms (RFLPs), the molecular markers that underlie multilocus DNA fingerprinting (MLDF), have historically been employed for this purpose, but over the past two decades, there has been an irreversible shift toward high-throughput single-nucleotide polymorphisms (SNPs). In this study, we conducted a comparative analysis of archived MLDF results and new data from whole-genome SNP genotyping (SNPg) among 18 divergently selected breeds representing a large sample of the world gene pool. As a result, we obtained data that fit the general concept of the phylogenetic distribution of the studied breeds and compared them with RFLP and SNP markers. RFLPs were found to be useful markers for retrospective assessment of changes in the genetic architecture and variability underlying the phenotypic variation in chicken populations, especially when samples from previous generations used for MLDF are unavailable for SNPg. These results can facilitate further research necessary to assess the possibility of extrapolating previous MLDF results to study the long-term dynamics of genetic diversity in various small chicken germplasm populations over time. In general, the whole-genome characterization of populations and breeds by multiple SNP loci will further form the basis for the development and implementation of genomic selection with the aim of effective use of the genetic potential of the domestic gene pool in the poultry industry.

Globe artichoke is an important vegetable of the Mediterranean basin. Its primary gene pool (GP1) consists of wild types ofCynara cardunculus. Crosses between the wild types and the cultivars (artichoke and cardoon) are fully fertile. In accordance, analyses of molecular markers revealed high genetic identity between the wild types and the cultivars. Hence, all these taxa are grouped together as conspecific varieties withinC.cardunculus. Several other wildCynaraspecies thrive in the Mediterranean basin. Of these,C. syriaca,C. algarbiensis,C. baeticaandC. humiliswere tested and found to be part of the secondary gene pool (GP2) of artichoke, as they were rather difficult to cross with either wild or cultivatedC. cardunculusand the few hybrids obtained were semi-sterile. In accordance, molecular genetic markers suggest that these wildCynaraspecies indeed diverged fromC. cardunculus. Four additionalCynaraspecies thrive in the Mediterranean basin, namelyC. cornigera,C. cyrenaica,C. tournefortiiandC. makrisii. There is no information on the crossability of these four species with artichoke, but molecular markers suggest that they may also belong to the secondary gene pool of the crop. Considering some attractive, variable characteristics of each of the GP2 species, such as earliness, albinism, dwarfism and diverse flavors, these wild species might be of great interest for artichoke breeders.

In the present study, we investigated the genetic variability among 49 new isolates of trypanosomatids from phytophagous Hemiptera by means of morphological characters, growth features, and biochemical (enzymes of ornithine-arginine cycle) and molecular markers (based on spliced-leader, and ribosomal genes). From 402 phytophagous insects dissected and examined for the presence of trypanosomatids, 228 species belonging to Pyrrhocoridae, Coreidae, Lygaeidae, and Pentatomidae families harbored trypanosomatids in their salivary glands, or digestive tubes. Among these insects, 211 carried promastigotes and only 17 had choanomastigote forms. The results show a strong association among morphology, growth features, and biochemical and molecular markers and reveal the genetic diversity of the isolates, which were assigned to Crithidia, Phytomonas, and Leptomonas; we found genetic polymorphism within all these genera, thus indicating high genetic variability among trypanosomatids from phytophagous insects.

Melocactus glaucescens (Cactaceae) is a critically endangered species endemic to north‐eastern Brazil. It grows in sympatry with other congeneric species and there is evidence for hybridization among them. We evaluated the levels of genetic and morphological variability and their substructuring between populations of M. glaucescens and sympatric species, and we tested for the occurrence of natural hybridization. Genetic variability was investigated using 12 allozyme loci, and morphological variability was investigated using multivariate morphometric analyses of 18 vegetative characters in nine natural populations of M. glaucescens, Melocactus ernestii, Melocactus concinnus and two distinct morphs of putative hybrids (Melocactus ×albicephalus). Genetic variability was low in all populations (P = 7.7–41.7, A = 0.3–1.7, He = 0.009–0.096), and all taxa displayed a deficit in heterozygotes. Low genetic structuring and moderate morphological structuring were found for M. glaucescens (FST = 0.045, AMRPP = 0.16) and M. concinnus (FST = 0.022, AMRPP = 0.11). The results obtained are inconclusive with respect to confirming the hypothesis of occurrence of hybridization because of an absence of diagnostic loci in the presumed parental species. The presence of several private alleles and the absence of linkage disequilibrium in the putative hybrids indicate that M. albicephalus should be treated as a distinct species, and not given hybrid status as recently stated by a number of authors. The large number of exclusive alleles and the levels of morphological structuring in the populations of M. glaucescens are important factors that need to be considered in the definition of strategies for the conservation of this species.

The relationships between StH-genomic species Elymus mutabilis (Drob.) Tzvel. and E. transbaicalensis (Nevski) Tzvel. were examined using biosystematic and biochemical (SDS electrophoresis of endosperm proteins) methods. The results showed the following. (1) There is interspecific morphological discreteness that permits assigning most individuals from the wild to a definite species. However, self-fertile intermediate individuals of introgressive origin were found. (2) Both taxa exhibited marked specificity of electrophoretic characteristics of endosperm proteins. (3) The species form two separate recombination gene pools (RGPs). Thus, E. mutabilis and E. transbaicalensis should be regarded as two distinct species. Nevertheless, there is some genetic exchange and unidirectional gene flow between the RGPs, especially in secondary (successive) habitats where mixed populations are observed. Two RGPs form the single introgressive gene pool (IGP), which includes other StH-genomic species of Northern Eurasia.

Sugarcane is an important crop as the main raw material producing sugar and as an energy source in the world. In Indonesia, sugarcane is one of the most crucial industrial plants due to sugar being regarded as a strategic food commodity. The slow supply of conventional sugarcane seeds often hinders the spread of the new superior varieties program, positioning tissue culture technique as an option to accelerate that program. However, somaclonal variation was reported in sugarcane seeds from callus culture. This study aims to determine the genetic variation in sugarcane seeds from cuttings and callus culture using molecular and morphological markers. The PS 864 variety was used to assess genetic variation of seeds cane from callus culture and cuttings. The results show no genetic variation in seeds cane from cuttings, while in seeds cane from callus culture there is a tendency for genetic variation of 4.6-11.6% based on the polymorphic RAPD bands. However, somaclonal variations are found in the phenotype of sugarcane seedlings from cuttings and callus culture, in leaves, stems and buds. The results of this study indicated that the more callus subcultures represent the greater tendency of genetic variation in sugarcane seeds.