Inoculum at the time of SARS-CoV-2 exposure and risk of disease severity.

A relationship between the infecting dose and the risk of disease severity has not been demonstrated for SARS-CoV-2 infection. Here, we report three clusters of individuals that were potentially exposed to distinct inoculum in Madrid. Overall each group developed divergent clinical forms of COVID-19.

On the allopolyploid origin and genome structure of the closely related species Hordeum secalinum and Hordeum capense inferred by molecular karyotyping.

Background And Aims: To provide additional information to the many phylogenetic analyses conducted within Hordeum , here the origin and interspecific affinities of the allotetraploids Hordeum secalinum and Hordeum capense were analysed by molecular karyotyping.

Methods: Karyotypes were determined using genomic in situ hybridization (GISH) to distinguish the sub-genomes and , plus fluorescence in situ hybridization (FISH)/non-denaturing (ND)-FISH to determine the distribution of ten tandem repetitive DNA sequences and thus provide chromosome markers.

Key Results: Each chromosome pair in the six accessions analysed was identified, allowing the establishment of homologous and putative homeologous relationships.

Sequencing of long stretches of repetitive DNA.

Repetitive DNA is widespread in eukaryotic genomes, in some cases making up more than 80% of the total. SSRs are a type of repetitive DNA formed by short motifs repeated in tandem arrays. In some species, SSRs may be organized into long stretches, usually associated with the constitutive heterochromatin.

Allopolyploidy and the complex phylogenetic relationships within the Hordeum brachyantherum taxon.

Hordeum brachyantherum Nevski includes two subspecies: the diploid (2×) subsp. californicum, and subsp. brachyantherum, which itself includes a tetraploid (4×) and a hexaploid (6×) cytotype.

Comparative analysis of gene expression among species of different ploidy.

Interspecific comparative studies require that expression data be comparable among species, and when species with different levels of ploidy are contemplated the relative expression per cell should be obtained for accurate comparisons to be made. Quantitative reverse-transcription-PCR is the most popular and sensitive technique for the detection and quantification of mRNA in gene expression analysis. In recent years it has become clear that the choice of reference genes for the normalization of expression data is very important.

Chromosomal characterization of the three subgenomes in the polyploids of Hordeum murinum L.: new insight into the evolution of this complex.

Hordeum murinum L. is a species complex composed of related taxa, including the subspecies glaucum, murinum and leporinum. However, the phylogenetic relationships between the different taxa and their cytotypes, and the origin of the polyploid forms, remain points of controversy.

The evolutionary history of sea barley (Hordeum marinum) revealed by comparative physical mapping of repetitive DNA.

Background And Aims: Hordeum marinum is a species complex that includes the diploid subspecies marinum and both diploid and tetraploid forms of gussoneanum. Their relationships, the rank of the taxa and the origin of the polyploid forms remain points of debate. The present work reports a comparative karyotype analysis of six H.

Cytogenetic diversity of SSR motifs within and between Hordeum species carrying the H genome: H. vulgare L. and H. bulbosum L.

Non-denaturing FISH (ND-FISH) was used to compare the distribution of four simple sequence repeats (SSRs)-(AG) n , (AAG) n , (ACT) n and (ATC) n -in somatic root tip metaphase spreads of 12 barley (H. vulgare ssp. vulgare) cultivars, seven lines of their wild progenitor H.

Next-generation sequencing and syntenic integration of flow-sorted arms of wheat chromosome 4A exposes the chromosome structure and gene content.

Wheat is the third most important crop for human nutrition in the world. The availability of high-resolution genetic and physical maps and ultimately a complete genome sequence holds great promise for breeding improved varieties to cope with increasing food demand under the conditions of changing global climate. However, the large size of the bread wheat (Triticum aestivum) genome (approximately 17 Gb/1C) and the triplication of genic sequence resulting from its hexaploid status have impeded genome sequencing of this important crop species.

Novel simple sequence repeats (SSRs) detected by ND-FISH in heterochromatin of Drosophila melanogaster.

Background: In recent years, substantial progress has been made in understanding the organization of sequences in heterochromatin regions containing single-copy genes and transposable elements. However, the sequence and organization of tandem repeat DNA sequences, which are by far the majority fraction of D. melanogaster heterochromatin, are little understood.

Chromosomal detection of simple sequence repeats (SSRs) using nondenaturing FISH (ND-FISH).

Simple Sequence Repeats (SSRs) are known to be scattered and present in high number in eukaryotic genomes. We demonstrate that dye-labeled oligodeoxyribonucleotides with repeated mono-, di-, tri, or tetranucleotide motifs (15-20 nucleotides in length) have an unexpected ability to recognize SSR target sequences in non-denatured chromosomes. The results show that all these probes are able to invade chromosomes, independent of the size of the repeat motif, their nucleotide sequence, or their ability to form alternative B-DNA structures such as triplex DNA.

A novel, simple and rapid nondenaturing FISH (ND-FISH) technique for the detection of plant telomeres. Potential used and possible target structures detected.

We report a new technique-nondenaturing FISH (ND-FISH)-for the rapid detection of plant telomeres without the need for prior denaturation of the chromosomes. In its development, two modified, synthetic oligonucleotides, 21 nt in length, fluorescently labelled at their 5' and 3' ends and complementary to either the cytidine-rich (C(3)TA(3)) or guanosine-rich (T(3)AG(3)) telomeric DNA strands, were used as probes. The high binding affinity of these probes and the short hybridization time required allows the visualization of plant telomeres in less than an hour.

Increasing the physical markers of wheat chromosomes using SSRs as FISH probes.

In plants the marker sequences used to identify chromosomes are mainly repetitive DNA probes. Simple sequence repeats (SSRs) are major components of many plant genomes and could be good markers for chromosome identification. In a previous work, we reported the physical distribution of 4 oligonucleotides, (AG)12, (CAT)5, (AAC)5, and (AAG)5, on Triticum aestivum L.

The nonrandom distribution of long clusters of all possible classes of trinucleotide repeats in barley chromosomes.

This paper is the first to report the long-range organization of all possible classes of trinucleotide motifs in a higher plant genome. Fluorescent in situ hybridization (FISH), employing the synthetic oligonucleotides (AAC)5, (AAG)5, (AAT)5, (AGG)5, (CAC)5, (CAT)5, (CAG)5, (ACT)5, (ACG)5 and (GCC)5, was used to characterize the nonrandom and motif-dependent distribution of tandem arrays of trinucleotide repeats in the metaphase chromosomes and interphase nuclei of barley (Hordeum vulgare L.).

Characterization of the gene Mre11 and evidence of silencing after polyploidization in Triticum.

The MRE11 protein is a component of the highly conserved MRN complex, along with RAD50 and NBS1. This complex is crucial in the repair of breaks in double stranded DNA, and is involved in many other cell processes. The present paper reports the molecular characterization of Mre11 gene in all three genomes of wheat, making use of the diploid species Triticum monococcum (genome A) and Aegilops Tauschii (genome D), the tetraploid T.

Mapping of QTLs for androgenetic response based on a molecular genetic map of x Triticosecale Wittmack.

Quantitative trait loci (QTLs) for androgenetic response were mapped in a doubled haploid (DH) population derived from the F1 hybrid of 2 unrelated varieties of triticale, 'Torote' and 'Presto'. A molecular marker linkage map of this cross was previously constructed using 73 DH lines. This map contains 356 markers (18 random amplified 5 polymorphic DNA, 40 random amplified microsatellite polymorphics, 276 amplified fragment length polymorphisms, and 22 simple sequence repeats) and was used for QTL analysis.

The genomic composition of Tricepiro, a synthetic forage crop.

Chromosome in situ hybridization (FISH and GISH) is a powerful tool for determining the chromosomal location of specific sequences and for analysing genome organization and evolution. Tricepiro (2n = 6x = 42) is a synthetic cereal obtained by G. Covas in Argentina (1972), which crosses hexaploid triticale (2n = 6x = 42) and octoploid Trigopiro (2n = 8x = 56).

Chloroplast microsatellite polymorphisms in Vitis species.

The use of consensus chloroplast microsatellites primers for dicotyledonous chloroplast genomes revealed the existence of intra and interspecific length variation within the genus Vitis. Three chloroplast microsatellite loci were found to be polymorphic in samples of Vitis vinifera, Vitis berlandieri, Vitis riparia, and Vitis rupestris out of a total of 10 consensus primer pairs tested. These polymorphisms were always due to a variable number of mononucleotide residues within A and (or) T stretches in the amplified regions.

Species relationships between antifungal chitinase and nuclear rDNA (internal transcribed spacer) sequences in the genus Hordeum.

The sequences of the chitinase gene (Chi-26) and the internal transcribed spacer of 18S - 5.8S - 26S rDNA (ITS1) were determined to analyze the phylogenetic relationships among species representing the four basic genomes of the genus Hordeum. Grouping analysis based on data for Chi-26 gene sequences placed Hordeum secalinum (H genome) near the Hordeum murinum complex (Xu genome), and Hordeum bulbosum distant from the other species that carried the I genome.