Detailed cytogenetic analysis of three duck species (the northern pintail, mallard, and common goldeneye) and karyotype evolution in the family Anatidae (Anseriformes, Aves).

Galliformes and Anseriformes are two branches of the Galloanserae group, basal to other Neognathae. In contrast to Galliformes, Anseriformes have not been thoroughly researched by cytogenetic methods. This report is focused on representatives of Anseriformes and the evolution of their chromosome sets.

Supernumerary Chromosomes Enhance Karyotypic Diversification of Narrow-Headed Voles of the Subgenus Stenocranius (Rodentia, Mammalia).

The subgenus Stenocranius contains two cryptic species: Lasiopodomys gregalis (subdivided into three allopatrically distributed and genetically well-isolated lineages A, B, and C) and Lasiopodomys raddei. To identify karyotype characteristics of this poorly studied cryptic species complex, we used comparative cytogenetic analysis of 138 individuals from 41 localities in South Siberia and Mongolia. A detailed description of the L.

Features of SARS-CoV-2 Replication in Various Types of Reptilian and Fish Cell Cultures.

Background: SARS-CoV-2 can enter the environment from the feces of COVID-19 patients and virus carriers through untreated sewage. The virus has shown the ability to adapt to a wide range of hosts, so the question of the possible involvement of aquafauna and animals of coastal ecosystems in maintaining its circulation remains open.

Methods: the aim of this work was to study the tropism of SARS-CoV-2 for cells of freshwater fish and reptiles, including those associated with aquatic and coastal ecosystems, and the effect of ambient temperature on this process.

Comparative studies of X chromosomes in Cervidae family.

The family Cervidae is the second most diverse in the infraorder Pecora and is characterized by variability in the diploid chromosome numbers among species. X chromosomes in Cervidae evolved through complex chromosomal rearrangements of conserved segments within the chromosome, changes in centromere position, heterochromatic variation, and X-autosomal translocations. The family Cervidae consists of two subfamilies: Cervinae and Capreolinae.

Maps of Constitutive-Heterochromatin Distribution for Four Species (Mustelidae, Carnivora, Mammalia) Show the Formative Role of Macrosatellite Repeats in Interspecific Variation of Chromosome Structure.

Constitutive-heterochromatin placement in the genome affects chromosome structure by occupying centromeric areas and forming large blocks. To investigate the basis for heterochromatin variation in the genome, we chose a group of species with a conserved euchromatin part: the genus [stone marten ( 2n = 38), sable (, 2n = 38, pine marten ( 2n = 38), and yellow-throated marten (, 2n = 40)]. We mined the stone marten genome for the most abundant tandem repeats and selected the top 11 macrosatellite repetitive sequences.

Comparative Studies of Karyotypes in the Cervidae Family.

The family Cervidae is the second most diverse family in the infraorder Pecora and is characterized by a striking variability in the diploid chromosome numbers among species, ranging from 6 to 70. Chromosomal rearrangements in Cervidae have been studied in detail by chromosome painting. There are many comparative cytogenetic data for both subfamilies (Cervinae and Capreolinae) based on homologies with chromosomes of cattle and Chinese muntjac.

The Cytogenetic Map of the Nile Crocodile (, Crocodylidae, Reptilia) with Fluorescence In Situ Localization of Major Repetitive DNAs.

Tandemly arranged and dispersed repetitive DNA sequences are important structural and functional elements that make up a significant portion of vertebrate genomes. Using high throughput, low coverage whole genome sequencing followed by bioinformatics analysis, we have identified seven major tandem repetitive DNAs and two fragments of LTR retrotransposons in the genome of the Nile crocodile (, 2n = 32). The repeats showed great variability in structure, genomic organization, and chromosomal distribution as revealed by fluorescence in situ hybridization (FISH).

Karyotype Evolution in 10 Pinniped Species: Variability of Heterochromatin versus High Conservatism of Euchromatin as Revealed by Comparative Molecular Cytogenetics.

Pinnipedia karyotype evolution was studied here using human, domestic dog, and stone marten whole-chromosome painting probes to obtain comparative chromosome maps among species of Odobenidae (), Phocidae (, , , , ), and Otariidae (, , , and ). Structural and functional chromosomal features were assessed with telomere repeat and ribosomal-DNA probes and by CBG (C-bands revealed by barium hydroxide treatment followed by Giemsa staining) and CDAG (Chromomycin A3-DAPI after G-banding) methods. We demonstrated diversity of heterochromatin among pinniped karyotypes in terms of localization, size, and nucleotide composition.

Evolution of the Human Chromosome 13 Synteny: Evolutionary Rearrangements, Plasticity, Human Disease Genes and Cancer Breakpoints.

The history of each human chromosome can be studied through comparative cytogenetic approaches in mammals which permit the identification of human chromosomal homologies and rearrangements between species. Comparative banding, chromosome painting, Bacterial Artificial Chromosome (BAC) mapping and genome data permit researchers to formulate hypotheses about ancestral chromosome forms. Human chromosome 13 has been previously shown to be conserved as a single syntenic element in the Ancestral Primate Karyotype; in this context, in order to study and verify the conservation of primate chromosomes homologous to human chromosome 13, we mapped a selected set of BAC probes in three platyrrhine species, characterised by a high level of rearrangements, using fluorescence in situ hybridisation (FISH).

Comparative Chromosome Mapping of Musk Ox and the X Chromosome among Some Bovidae Species.

Bovidae, the largest family in Pecora infraorder, are characterized by a striking variability in diploid number of chromosomes between species and among individuals within a species. The bovid X chromosome is also remarkably variable, with several morphological types in the family. Here we built a detailed chromosome map of musk ox (), a relic species originating from Pleistocene megafauna, with dromedary and human probes using chromosome painting.

An integrated chromosome-scale genome assembly of the Masai giraffe (Giraffa camelopardalis tippelskirchi).

Background: The Masai giraffe (Giraffa camelopardalis tippelskirchi) is the largest-bodied giraffe and the world's tallest terrestrial animal. With its extreme size and height, the giraffe's unique anatomical and physiological adaptations have long been of interest to diverse research fields. Giraffes are also critical to ecosystems of sub-Saharan Africa, with their long neck serving as a conduit to food sources not shared by other herbivores.

Improving Illumina assemblies with Hi-C and long reads: An example with the North African dromedary.

Researchers have assembled thousands of eukaryotic genomes using Illumina reads, but traditional mate-pair libraries cannot span all repetitive elements, resulting in highly fragmented assemblies. However, both chromosome conformation capture techniques, such as Hi-C and Dovetail Genomics Chicago libraries and long-read sequencing, such as Pacific Biosciences and Oxford Nanopore, help span and resolve repetitive regions and therefore improve genome assemblies. One important livestock species of arid regions that does not have a high-quality contiguous reference genome is the dromedary (Camelus dromedarius).

Evolution of gene regulation in ruminants differs between evolutionary breakpoint regions and homologous synteny blocks.

The role of chromosome rearrangements in driving evolution has been a long-standing question of evolutionary biology. Here we focused on ruminants as a model to assess how rearrangements may have contributed to the evolution of gene regulation. Using reconstructed ancestral karyotypes of Cetartiodactyls, Ruminants, Pecorans, and Bovids, we traced patterns of gross chromosome changes.

A combined banding method that allows the reliable identification of chromosomes as well as differentiation of AT- and GC-rich heterochromatin.

Сonstitutive heterochromatin areas are revealed by differential staining as C-positive chromosomal regions. These C-positive bands may greatly vary by location, size, and nucleotide composition. CBG-banding is the most commonly used method to detect structural heterochromatin in animals.

The Case of X and Y Localization of Nucleolus Organizer Regions (NORs) in (Cetartiodactyla, Mammalia).

There are differences in number and localization of nucleolus organizer regions (NORs) in genomes. In mammalian genomes, NORs are located on autosomes, which are often situated on short arms of acrocentric chromosomes and more rarely in telomeric, pericentromeric, or interstitial regions. In this work, we report the unique case of active NORs located on gonоsomes of a eutherian mammal, the Javan mouse-deer ().

X Chromosome Evolution in Cetartiodactyla.

The phenomenon of a remarkable conservation of the X chromosome in eutherian mammals has been first described by Susumu Ohno in 1964. A notable exception is the cetartiodactyl X chromosome, which varies widely in morphology and G-banding pattern between species. It is hypothesized that this sex chromosome has undergone multiple rearrangements that changed the centromere position and the order of syntenic segments over the last 80 million years of Cetartiodactyla speciation.

Contrasting origin of B chromosomes in two cervids (Siberian roe deer and grey brocket deer) unravelled by chromosome-specific DNA sequencing.

Background: B chromosomes are dispensable and variable karyotypic elements found in some species of animals, plants and fungi. They often originate from duplications and translocations of host genomic regions or result from hybridization. In most species, little is known about their DNA content.

Comparative Chromosome Map and Heterochromatin Features of the Gray Whale Karyotype (Cetacea).

Cetacean karyotypes possess exceptionally stable diploid numbers and highly conserved chromosomes. To date, only toothed whales (Odontoceti) have been analyzed by comparative chromosome painting. Here, we studied the karyotype of a representative of baleen whales, the gray whale (Eschrichtius robustus, Mysticeti), by Zoo-FISH with dromedary camel and human chromosome-specific probes.

The Ancestral Carnivore Karyotype As Substantiated by Comparative Chromosome Painting of Three Pinnipeds, the Walrus, the Steller Sea Lion and the Baikal Seal (Pinnipedia, Carnivora).

Karyotype evolution in Carnivora is thoroughly studied by classical and molecular cytogenetics and supplemented by reconstructions of Ancestral Carnivora Karyotype (ACK). However chromosome painting information from two pinniped families (Odobenidae and Otariidae) is noticeably missing. We report on the construction of the comparative chromosome map for species from each of the three pinniped families: the walrus (Odobenus rosmarus, Odobenidae-monotypic family), near threatened Steller sea lion (Eumetopias jubatus, Otariidae) and the endemic Baikal seal (Pusa sibirica, Phocidae) using combination of human, domestic dog and stone marten whole-chromosome painting probes.