Anthropogenic activity is the top factor directly related to the extinction of several animal species. The last Steller's sea cow (Hydrodamalis gigas) population on the Commander Islands (Russia) was ...wiped out in the second half of the 18
century due to sailors and fur traders hunting it for the meat and fat. However, new data suggests that the extinction process of this species began much earlier. Here, we present a nuclear de novo assembled genome of H. gigas with a 25.4× depth coverage. Our results demonstrate that the heterozygosity of the last population of this animal is low and comparable to the last woolly mammoth population that inhabited Wrangel Island 4000 years ago. Besides, as a matter of consideration, our findings also demonstrate that the extinction of this marine mammal starts along the North Pacific coastal line much earlier than the first Paleolithic humans arrived in the Bering sea region.
Body size reduction, also known as miniaturization, is an important evolutionary process that affects a number of physiological and phenotypic traits and helps animals conquer new ecological niches. ...However, this process is poorly understood at the molecular level. Here, we report genomic and transcriptomic features of arguably the smallest known insect-the parasitoid wasp, Megaphragma amalphitanum (Hymenoptera: Trichogrammatidae). In contrast to expectations, we find that the genome and transcriptome sizes of this parasitoid wasp are comparable to other members of the Chalcidoidea superfamily. Moreover, compared to other chalcid wasps the gene content of M. amalphitanum is remarkably conserved. Intriguingly, we observed significant changes in M. amalphitanum transposable element dynamics over time, in which an initial burst was followed by suppression of activity, possibly due to a recent reinforcement of the genome defense machinery. Overall, while the M. amalphitanum genomic data reveal certain features that may be linked to the unusual biological properties of this organism, miniaturization is not associated with a large decrease in genome complexity.
Prunus persica is one of the main stone fruit crops in Crimea and southern Russia. The P. persica genome has recently been sequenced and annotated in good quality. However, for a deeper assessment of ...the peach genome, it is necessary to include in the research other cultivars that are in the collection of the Nikitsky Botanical Garden. The cultivars of the Nikitsky Botanical Garden are unique and differ from Western European and American ones, as they are derived from cultivars and forms originating from Central Asian, North Caucasian, Transcaucasian and Eastern European countries. In this paper, we present the assembly of the P. persica cv. 'Sovetskiy' genome obtained using Oxford Nanopore long reads and Illumina short reads by hybrid assembly methods. The assembled genome of P. persica cv. 'Sovetskiy' is 206.26 MB in 226 scaffolds, with N50 24 Mb, including 8 chromosomes. It contains 27140 coding genes, 26973 (99.38%) of which are annotated in at least one functional database. More than 36.05% of the genome regions were identified as repeating elements.
Kaiso Regulates DNA Methylation Homeostasis Kaplun, Darya; Starshin, Alexey; Sharko, Fedor ...
International journal of molecular sciences,
07/2021, Letnik:
22, Številka:
14
Journal Article
Recenzirano
Odprti dostop
Gain and loss of DNA methylation in cells is a dynamic process that tends to achieve an equilibrium. Many factors are involved in maintaining the balance between DNA methylation and demethylation. ...Previously, it was shown that methyl-DNA protein Kaiso may attract NCoR, SMRT repressive complexes affecting histone modifications. On the other hand, the deficiency of Kaiso resulted in reduced methylation of ICR in
locus and
promoter in mouse embryonic fibroblasts. However, nothing is known about how Kaiso influences DNA methylation at the genome level. Here we show that deficiency of Kaiso led to whole-genome hypermethylation, using Kaiso deficient human renal cancer cell line obtained via CRISPR/CAS9 genome editing. However, Kaiso serves to protect genic regions, enhancers, and regions with a low level of histone modifications from demethylation. We detected hypomethylation of binding sites for Oct4 and Nanog in Kaiso deficient cells. Kaiso immunoprecipitated with de novo DNA methyltransferases DNMT3a/3b, but not with maintenance methyltransferase DNMT1. Thus, Kaiso may attract methyltransferases to surrounding regions and modulate genome methylation in renal cancer cells apart from being methyl DNA binding protein.
Display omitted
•Half-extinct species flock of brown trout (5 forms) was studied using aDNA and WGS.•mtDNA and nuclear data confirm the monophyly and recent origin of Sevan trouts.•Stepwise evolution ...from riverine to lacustrine mode of life was revealed.•Climatic oscillations were the likely trigger for speciation of lacustrine forms.•A few SNPs under selection may be responsible for assortative mating.
Five ecologically and phenotypically divergent ecomorphs of the genus Salmo are known from a landlocked alpine lake in the Caucasus, Lake Sevan. It is an example of sympatric diversification within a species-rich lineage with predominate mode of speciation being allopatric. The diversification of Sevan trouts was accompanied by spawning resource partitioning. Four lacustrine ecomorphs with different temporal-spatial spawning strategies and divergent morphology and coloration evolved along with a fifth ecomorph, brook trout, inhabiting the tributaries. Unfortunately, the Sevan trout diversity was almost destroyed by human activity, with two ecomorphs becoming extinct in the 1980s. We performed reconstruction of the evolutionary history of Sevan trouts based on high-throughput sequencing of both contemporary and historical DNA (∼ 50 y.o.) of all Sevan trout ecomorphs. Our study of complete mitogenomes along with genome-wide SNP data revealed the monophyly of four lacustrine ecomorphs and local brook trout, all derived from the anadromous form Caspian salmon, S. caspius. The species tree suggests a scenario of stepwise evolution from riverine to lacustrine spawning. Three genomic clusters were revealed, of which two refer to the riverine and lacustrine spawners within the flock of Sevan trouts (with FST value = 0.069). A few SNP outliers under selection were discovered that could be responsible for assortative mating based on visual recognition. The Holocene climatic oscillations and the desiccation of tributaries could have played an important role in the origin of lacustrine spawning. The relationships between lacustrine ecomorphs were not yet fully resolved. This radiation warrants further investigation.
Circular RNAs (circRNAs) are covalently closed-loop RNAs with critical regulatory roles in cells. Tens of thousands of circRNAs have been unveiled due to the recent advances in high throughput RNA ...sequencing technologies and bioinformatic tools development. At the same time, polymerase chain reaction (PCR) cross-validation for circRNAs predicted by bioinformatic tools remains an essential part of any circRNA study before publication.
Here, we present the CircPrime web-based platform, providing a user-friendly solution for DNA primer design and thermocycling conditions for circRNA identification with routine PCR methods.
User-friendly CircPrime web platform ( http://circprime.elgene.net/ ) works with outputs of the most popular bioinformatic predictors of circRNAs to design specific circular RNA primers. CircPrime works with circRNA coordinates and any reference genome from the National Center for Biotechnology Information database).
The orphan insulin receptor-related receptor (IRR) encoded by insrr gene is the third member of the insulin receptor family, also including the insulin receptor (IR) and the insulin-like growth ...factor receptor (IGF-1R). IRR is the extracellular alkaline medium sensor. In mice, insrr is expressed only in small populations of cells in specific tissues, which contain extracorporeal liquids of extreme pH. In particular, IRR regulates the metabolic bicarbonate excess in the kidney. In contrast, the role of IRR during Xenopus laevis embryogenesis is unknown, although insrr is highly expressed in frog embryos. Here, we examined the insrr function during the Xenopus laevis early development by the morpholino-induced knockdown. We demonstrated that insrr downregulation leads to development retardation, which can be restored by the incubation of embryos in an alkaline medium. Using bulk RNA-seq of embryos at the middle neurula stage, we showed that insrr downregulation elicited a general shift of expression towards genes specifically expressed before and at the onset of gastrulation. At the same time, alkali treatment partially restored the expression of the neurula-specific genes. Thus, our results demonstrate the critical role of insrr in the regulation of the early development rate in Xenopus laevis.
Fig mosaic disease is spread worldwide and is believed to have a viral etiology. Divergent isolates of grapevine badnavirus 1 (GBV1), named fGBV1, were discovered on Ficus carica, F. palmata, F. ...virgata, and F. afghanistanica in the fig germplasm collection of the Nikita Botanical Gardens, Russia, expanding the list of viruses infecting this crop. The complete genomes of five fGBV1 isolates from F. carica and F. palmata trees were determined using high-throughput and Sanger sequencing. The genomes comprised 7283 base pairs, contained four overlapping open reading frames, were 99.7 to 99.9% identical to each other, and related to GBV1 (83.2% identity). The reverse transcriptase RNase H genome regions of fGBV1 and GBV1 share 84.6% identity, indicating that fGBV1 is a divergent isolate of GBV1, which was found on the new natural hosts from a different family (Moraceae). Further, fGBV1-specific primers were developed to detect the virus using RT-PCR. Survey of 47 trees, belonging to four fig species and 14 local and introduced F. carica cultivars, showed the high fGBV1 prevalence in the collection (93.6%), including trees with no obvious symptoms of fig mosaic disease.
Interspecific hybridization has occurred relatively frequently during the evolution of vertebrates. This process usually abolishes reproductive isolation between the parental species. Moreover, it ...results in the exchange of genetic material and can lead to hybridogenic speciation. Hybridization between species has predominately been observed at the interspecific level, whereas intergeneric hybridization is rarer. Here, using whole-genome sequencing analysis, we describe clear and reliable signals of intergeneric introgression between the three-spined stickleback (
Gasterosteus aculeatus
) and its distant mostly freshwater relative the nine-spined stickleback (
Pungitius pungitius
) that inhabit northwestern Russia. Through comparative analysis, we demonstrate that such introgression phenomena apparently take place in the moderate-salinity White Sea basin, although it is not detected in Japanese sea stickleback populations. Bioinformatical analysis of the sites influenced by introgression showed that they are located near transposable elements, whereas those in protein-coding sequences are mostly found in membrane-associated and alternative splicing-related genes.
PDF
