#geneticpolymorphism

[cytgen]

Abstract Two species of the genus Galinsoga, G. parviflora Cav. and G. quadriradiata Ruiz and Pav., are among the most successful invasive plants causing significant damage to natural- and agroecosystems. Their natural distribution range extends from North to South America, and the adventitious part of the range includes all continents except Antarctica. Despite the practical importance of G. parviflora and G. quadriradiata, the genetic diversity of European populations of these species remains unexplored. In this study, ISSR markers were used to study Ukrainian populations of G. parviflora and G. quadriradiata and compared them with plants from Poland, Lithuania, and Portugal. The results obtained indicate the low genetic diversity (Shannon’s index I = 0.124) of G. quadriradiata populations, which is probably due to the small size of the original population introduced to the Old World from America. In contrast, the genetic diversity in G. parviflora populations is significantly higher (I = 0.254). Some genotypes of G. parviflora have a wide geographical distribution and, at the same time, different genotypes occur in the same area. The data obtained are in good agreement with the hypothesis that the main way of the invasion of Galinsoga species in the Old World was escape from botanical gardens. Among the samples examined, several forms of hybrid nature were identified, probably originating from hybrids between G. parviflora and G. quadriradiata, followed by subsequent backcrossing with one of the parent species.

[agappediagnostics]

GENETIC POLYMORPHISM (SUSCEPTIBLE MUTATIONS), DOES IT CONTRIBUTE TO THE HIGHER COVID-19 BURDEN IN KERALA?As everybody knows, Kerala is the diabetes capital (<20%) of India & concomitantly, we have highest number of cardiovascular (CVS) deaths too (16%).

https://www.agappe.com/in/blog-details/227

[cytgen]

Abstract The ITS1-5.8S-ITS2 (ITS1-2) region of the 35S rDNA is widely used for molecular barcoding and in the phylogenetics of plants. It is believed that, due to concerted evolution, all copies of 35S rDNA in eukaryotic genomes should be effectively homogenized. However, the existence of intragenomic polymorphism of the ITS1-2 region in plant genomes has recently been demonstrated, which may be a consequence of hybridization within or between species. In this study, the intragenomic polymorphism of the ITS1-2 region was evaluated using Illumina amplicon sequencing in accessions of two invasive species of the genus Reynoutria, R. japonica and R. sachalinensis, from Ukraine and Romania. Hybridization between these species can lead to the emergence of more aggressive invasive forms. The ITS1-2 sequences of the species studied were found to be represented by some major and minor subclasses/variants, indicating their incomplete homogenization. The number of major variants range from two in R. japonica to six in R. sachalinensis. The ITS1-2 variants that are widespread in the genome of one species may be present at low levels in another species, indicating possible interspecies hybridization. The obtained results show that the ITS1-2 intragenomic polymorphism must be taken into account when performing barcoding, reconstructing the phylogeny of low-level taxa, and for the identification of hybrid forms.

[cytgen]

Abstract Tandemly arranged repetitive regions (repeats) that encode 5S rRNA (5S rDNA) are an indispensable component of eukaryotic genomes. Typically, 5S rDNA repeats within a genome are very similar due to the concerted nature of the evolution of this type of repeats. Each 5S rDNA repeat consists of an evolutionarily conserved coding sequence (CDS) and a variable intergenic spacer (IGS). 5S rDNA is a popular model for studying the molecular evolution of repetitive sequences, and the high rate of IGS mutations determines its wide use in phylogenetic analysis of closely related taxa. Nevertheless, 5S rDNA remains unexplored for many groups of higher plants, especially for the Plumbaginaceae family. Some taxa of this family are endemic to southern Ukraine and listed in the Red Book. However, their taxonomic status is controversial, and its clarification requires the use of molecular phylogenetic methods. In this work, we examined the molecular organization of 5S rDNA for representatives of four genera of the tribe Limonieae, the largest in the family Plumbaginaceae. It was shown that the CDS of 5S rDNA of representatives of the genera Limonium, Armeria, and Ceratolimon possess single mutations that do not affect the formation of the secondary structure of 5S rRNA. In contrast, in the genomes of Goniolimon species, in addition to functionally normal 5S rDNA repeats, numerous pseudogenes were found that do not evolve in a concerted manner and contain numerous mutations in the CDS that disrupt the secondary structure of 5S rRNA. A significant phylogenetic distance between representatives of the subgenera Pteroclados and Limonium of the genus Limonium indicates that Pteroclados can be considered a separate genus. The high rate of molecular evolution makes 5S rDNA IGS a convenient tool for the reconstruction of phylogenetic relationships within the studied genera of the tribe Limonieae and the barcoding of Ukrainian endemics of the genus Limonium.

Keywords: 5S rDNA genetic polymorphism molecular evolution and phylogeny repetitive sequences pseudogenes Armeria Ceratolimon Goniolimon Limonium

[cytgen]

Abstract The genus Muscari Mill. (Asparagaceae Juss.) includes about 80 species distributed in Eurasia, mainly in the Mediterranean region. Recent molecular phylogenetic studies have shown that the taxa belonging to this group form a monophyletic clade and are closely related. However, the phylogeny and status of some taxa of Muscari sensu lato remain controversial. So far, most phylogenetic studies of the genus Muscari have used almost exclusively Mediterranean plant material, while representatives of the genus from the Carpathian region remain unexplored. In this work, we used the sequencing of three regions of chloroplast DNA, psbA-trnH, trnT-L, and trnL-F, to clarify the phylogenetic relationships in the genus Muscari, to assess the genetic polymorphism and taxonomic status of Ukrainian populations of M. botryoides, as well as specimens of other Muscari species from the Carpathian region. According to the results of the phylogenetic analysis, the genus Muscari is a monophyletic group that includes three subgenera: Muscari, Muscarimia, and Pseudomuscari. Leopoldia species have been placed in the subgenus Muscari. Specimens of M. botryoides from Ukraine and Austria together with M. transsilvanicum from Romania and M. serpentinicum/M. sandrasicum from Turkey form the clade “Botryoides”, one of the three main clades identified in the subgenus Muscari. A significant genetic distance between Ukrainian specimens of M. botryoides, specimens of this species from other habitats, and other species of the genus Muscari allows us to consider the Ukrainian specimens of M. botryoides as a new, previously undescribed species. A comparison of the sequences of the investigated regions of the chloroplast genome revealed genetic differences between two groups of Ukrainian populations of M. botryoides, which can be interpreted as the existence of two intraspecific forms.