Varietal variation and chromosome behaviour during meiosis in Solanum tuberosum

Abstract Naturally occurring autopolyploid species, such as the autotetraploid potato Solanum tuberosum, face a variety of challenges during meiosis. These include proper pairing, recombination and correct segregation of multiple homologous chromosomes, which can form complex multivalent configurations at metaphase I, and in turn alter allelic segregation ratios through double reduction. Here, we present a reference map of meiotic stages in diploid and tetraploid S. tuberosum using fluorescence in situ hybridisation (FISH) to differentiate individual meiotic chromosomes 1 and 2. A diploid-like behaviour at metaphase I involving bivalent configurations was predominant in all three tetraploid varieties. The crossover frequency per bivalent was significantly reduced in the tetraploids compared with a diploid variety, which likely indicates meiotic adaptation to the autotetraploid state. Nevertheless, bivalents were accompanied by a substantial frequency of multivalents, which varied by variety and by chromosome (7–48%). We identified possible sites of synaptic partner switching, leading to multivalent formation, and found potential defects in the polymerisation and/or maintenance of the synaptonemal complex in tetraploids. These findings demonstrate the rise of S. tuberosum as a model for autotetraploid meiotic recombination research and highlight constraints on meiotic chromosome configurations and chiasma frequencies as an important feature of an evolved autotetraploid meiosis.

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Rapid Multi-Hybridisation FISH Screening for Balanced Porcine Reciprocal Translocations Suggests a Much Higher Abnormality Rate Than Previously Appreciated

Cells ◽

10.3390/cells10020250 ◽

2021 ◽

Vol 10 (2) ◽

pp. 250

Author(s):

Rebecca E O’Connor ◽

Lucas G Kiazim ◽

Claudia C Rathje ◽

Rebecca L Jennings ◽

Darren K Griffin

Keyword(s):

Semen Analysis ◽

In Situ Hybridisation ◽

Economic Loss ◽

Environmental Damage ◽

Fluorescence In Situ Hybridisation ◽

Reciprocal Translocations ◽

Chromosome Translocations ◽

Farrowing Rate ◽

Significant Economic Loss

With demand rising, pigs are the world’s leading source of meat protein; however significant economic loss and environmental damage can be incurred if boars used for artificial insemination (AI) are hypoprolific (sub-fertile). Growing evidence suggests that semen analysis is an unreliable tool for diagnosing hypoprolificacy, with litter size and farrowing rate being more applicable. Once such data are available, however, any affected boar will have been in service for some time, with significant financial and environmental losses incurred. Reciprocal translocations (RTs) are the leading cause of porcine hypoprolificacy, reportedly present in 0.47% of AI boars. Traditional standard karyotyping, however, relies on animal specific expertise and does not detect more subtle (cryptic) translocations. Previously, we reported development of a multiple hybridisation fluorescence in situ hybridisation (FISH) strategy; here, we report on its use in 1641 AI boars. A total of 15 different RTs were identified in 69 boars, with four further animals XX/XY chimeric. Therefore, 4.5% had a chromosome abnormality (4.2% with an RT), a 0.88% incidence. Revisiting cases with both karyotype and FISH information, we reanalysed captured images, asking whether the translocation was detectable by karyotyping alone. The results suggest that chromosome translocations in boars may be significantly under-reported, thereby highlighting the need for pre-emptive screening by this method before a boar enters a breeding programme.

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Connecting structure to function with the recovery of over 1000 high-quality metagenome-assembled genomes from activated sludge using long-read sequencing

Nature Communications ◽

10.1038/s41467-021-22203-2 ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Caitlin M. Singleton ◽

Francesca Petriglieri ◽

Jannie M. Kristensen ◽

Rasmus H. Kirkegaard ◽

Thomas Y. Michaelsen ◽

...

Keyword(s):

16S Rrna ◽

Wastewater Treatment Plants ◽

In Situ Hybridisation ◽

Amplicon Sequencing ◽

Rrna Genes ◽

Fluorescence In Situ Hybridisation ◽

Sequencing Data ◽

High Quality ◽

16S Rrna Amplicon Sequencing ◽

Long Read

AbstractMicroorganisms play crucial roles in water recycling, pollution removal and resource recovery in the wastewater industry. The structure of these microbial communities is increasingly understood based on 16S rRNA amplicon sequencing data. However, such data cannot be linked to functional potential in the absence of high-quality metagenome-assembled genomes (MAGs) for nearly all species. Here, we use long-read and short-read sequencing to recover 1083 high-quality MAGs, including 57 closed circular genomes, from 23 Danish full-scale wastewater treatment plants. The MAGs account for ~30% of the community based on relative abundance, and meet the stringent MIMAG high-quality draft requirements including full-length rRNA genes. We use the information provided by these MAGs in combination with >13 years of 16S rRNA amplicon sequencing data, as well as Raman microspectroscopy and fluorescence in situ hybridisation, to uncover abundant undescribed lineages belonging to important functional groups.

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Effects of the diploidisation process upon the 5S and 35S rDNA sequences in the allopolyploid species of the Dilatata group of Paspalum (Poaceae, Paniceae)

Australian Journal of Botany ◽

10.1071/bt18236 ◽

2019 ◽

Vol 67 (7) ◽

pp. 521

Author(s):

Magdalena Vaio ◽

Cristina Mazzella ◽

Marcelo Guerra ◽

Pablo Speranza

Keyword(s):

Evolutionary Dynamics ◽

In Situ Hybridisation ◽

5S Rdna ◽

Its Region ◽

Variable Number ◽

Rrna Genes ◽

Fluorescence In Situ Hybridisation ◽

Rdna Sites ◽

35S Rdna ◽

Genome Restructuring

The Dilatata group of Paspalum includes species and biotypes native to temperate South America. Among them, five sexual allotetraploids (x = 10) share the same IIJJ genome formula: P. urvillei Steud, P. dasypleurum Kunze ex Desv., P. dilatatum subsp. flavescens Roseng., B.R. Arrill. & Izag., and two biotypes P. dilatatum Vacaria and P. dilatatum Virasoro. Previous studies suggested P. intermedium Munro ex Morong & Britton and P. juergensii Hack. or related species as their putative progenitors and donors of the I and J genome, respectively, and pointed to a narrow genetic base for their maternal origin. It has not yet been established whether the various members of the Dilatata group are the result of a single or of multiple allopolyploid formations. Here, we aimed to study the evolutionary dynamics of rRNA genes after allopolyploidisation in the Dilatata group of Paspalum and shed some light into the genome restructuring of the tetraploid taxa with the same genome formula. We used double target fluorescence in situ hybridisation of 35S and 5S rDNA probes and sequenced the nrDNA internal transcribed spacer (ITS) region. A variable number of loci at the chromosome ends were observed for the 35S rDNA, from 2 to 6, suggesting gain and loss of sites. For the 5S rDNA, only one centromeric pair of signals was observed, indicating a remarkable loss after polyploidisation. All ITS sequences generated were near identical to the one found for P. intermedium. Although sequences showed a directional homogeneisation towards the putative paternal progenitor in all tetraploid species, the observed differences in the number and loss of rDNA sites suggest independent ongoing diploidisation processes in all taxa and genome restructuring following polyploidy.

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Molecular organization of mammalian meiotic chromosome axis revealed by expansion STORM microscopy

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1902440116 ◽

2019 ◽

Vol 116 (37) ◽

pp. 18423-18428 ◽

Cited By ~ 20

Author(s):

Huizhong Xu ◽

Zhisong Tong ◽

Qing Ye ◽

Tengqian Sun ◽

Zhenmin Hong ◽

...

Keyword(s):

Meiotic Chromosome ◽

Molecular Organization ◽

Homologous Chromosomes ◽

Meiotic Chromosomes ◽

C Terminus ◽

Stochastic Optical Reconstruction Microscopy ◽

Optical Reconstruction ◽

20 Nm ◽

Chromosome Axis

During prophase I of meiosis, chromosomes become organized as loop arrays around the proteinaceous chromosome axis. As homologous chromosomes physically pair and recombine, the chromosome axis is integrated into the tripartite synaptonemal complex (SC) as this structure’s lateral elements (LEs). While the components of the mammalian chromosome axis/LE—including meiosis-specific cohesin complexes, the axial element proteins SYCP3 and SYCP2, and the HORMA domain proteins HORMAD1 and HORMAD2—are known, the molecular organization of these components within the axis is poorly understood. Here, using expansion microscopy coupled with 2-color stochastic optical reconstruction microscopy (STORM) imaging (ExSTORM), we address these issues in mouse spermatocytes at a resolution of 10 to 20 nm. Our data show that SYCP3 and the SYCP2 C terminus, which are known to form filaments in vitro, form a compact core around which cohesin complexes, HORMADs, and the N terminus of SYCP2 are arrayed. Overall, our study provides a detailed structural view of the meiotic chromosome axis, a key organizational and regulatory component of meiotic chromosomes.

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Chromosome translocations detected by fluorescence in situ hybridisation (FISH)-a useful tool in population monitoring?

Toxicology Letters ◽

10.1016/s0378-4274(98)00068-x ◽

1998 ◽

Vol 96-97 (1-2) ◽

pp. 189-194 ◽

Cited By ~ 6

Author(s):

S Pressl

Keyword(s):

In Situ Hybridisation ◽

Population Monitoring ◽

Fluorescence In Situ Hybridisation ◽

Chromosome Translocations

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Monitoring HIV-1 treatment in immune-cell subsets with ultrasensitive fluorescence-in-situ hybridisation

The Lancet ◽

10.1016/s0140-6736(05)77222-6 ◽

1999 ◽

Vol 353 (9148) ◽

pp. 211-212 ◽

Cited By ~ 15

Author(s):

Bruce K Patterson ◽

Mary Ann Czerniewski ◽

John Pottage ◽

Michelle Agnoli ◽

Harold Kessler ◽

...

Keyword(s):

Immune Cell ◽

In Situ Hybridisation ◽

Fluorescence In Situ Hybridisation ◽

Immune Cell Subsets ◽

Hiv 1

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Synaptonemal complex proteins: occurrence, epitope mapping and chromosome disjunction

Journal of Cell Science ◽

10.1242/jcs.107.10.2749 ◽

1994 ◽

Vol 107 (10) ◽

pp. 2749-2760 ◽

Cited By ~ 48

Author(s):

M.J. Dobson ◽

R.E. Pearlman ◽

A. Karaiskakis ◽

B. Spyropoulos ◽

P.B. Moens

Keyword(s):

Synaptonemal Complex ◽

Fusion Proteins ◽

Epitope Mapping ◽

Core Protein ◽

Binding Capacity ◽

Polyclonal Antibodies ◽

Meiotic Chromosome ◽

Immunogold Labelling ◽

Chromosome Disjunction ◽

Metaphase I

We have used polyclonal antibodies against fusion proteins produced from cDNA fragments of a meiotic chromosome core protein, Cor1, and a protein present only in the synapsed portions of the cores, Syn1, to detect the occurrence and the locations of these proteins in rodent meiotic prophase chromosomes. The 234 amino acid Cor1 protein is present in early unpaired cores, in the lateral domains of the synaptonemal complex and in the chromosome cores when they separate at diplotene. A novel observation showed the presence of Cor1 axial to the metaphase I chromosomes and substantial amounts of Cor1 in association with pairs of sister centromeres. The centromere-associated Cor1 protein becomes dissociated from the centromeres at anaphase II and it is not found in mitotic metaphase centromeres. The extended presence of Cor1 suggests that it may have a role in chromosome disjunction by fastening chiasmata at metaphase I and by joining sister kinetochores, which ensures co-segregation at anaphase I. Two-colour immunofluorescence of Cor1 and Syn1 demonstrates that synapsis between homologous cores is initiated at few sites but advances rapidly relative to the establishment of new initiation sites. If the rapid advance of synapsis deters additional initiation sites between pairs of homologues, it may provide a mechanism for positive recombination interference. Immunogold epitope mapping of antibodies to four Syn1 fusion proteins places the amino terminus of Syn1 towards the centre of the synaptonemal complex while the carboxyl terminus extends well into the lateral domain of the synaptonemal complex. The Syn1 fusion proteins have a non-specific DNA binding capacity. Immunogold labelling of Cor1 antigens indicates that the lateral domain of the synaptonemal complex is about twice as wide as the apparent width of lateral elements when stained with electron-dense metal ions. Electron microscopy of shadow-cast surface-spread SCs confirms the greater width of the lateral domain. The implication of these dimensions is that the proteins that comprise the synaptic domain overlap with the protein constituents of the lateral domains of the synaptonemal complex more than was apparent from earlier observations. This arrangement suggests that direct interactions might be expected between some of the synaptonemal complex proteins.

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Short-term effects of carbon source on the competition of polyphosphate accumulating organisms and glycogen accumulating organisms

Water Science & Technology ◽

10.2166/wst.2004.0629 ◽

2004 ◽

Vol 50 (10) ◽

pp. 139-144 ◽

Cited By ~ 57

Author(s):

A. Oehmen ◽

Z. Yuan ◽

L.L. Blackall ◽

J. Keller

Keyword(s):

Carbon Source ◽

In Situ Hybridisation ◽

Operating Conditions ◽

Fluorescence In Situ Hybridisation ◽

Biological Phosphorus Removal ◽

Short Term ◽

Uptake Rates ◽

Polyphosphate Accumulating Organisms ◽

The Impact ◽

Short Term Effects

The effectiveness of enhanced biological phosphorus removal (EBPR) systems is directly affected by the competition of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). This study investigated the short-term effects of carbon source on PAO and GAO performance. The tests were designed to clearly determine the impact of volatile fatty acid (VFA) composition on the performance of two types of biomass, one enriched for PAOs and the other for GAOs. The two populations were enriched in separate reactors using identical operating conditions and very similar influent compositions with acetate as the sole carbon source. The only difference was that a very low level of phosphorus was present in the influent to the GAO reactor. The abundance of PAOs and GAOs was quantified using fluorescence in-situ hybridisation. The results clearly show that there are some very distinctive differences between PAOs and GAOs in their ability to utilise different carbon substrates. While both are able to take up acetate rapidly and completely, the GAOs are far slower at consuming propionate than the PAOs during short-term substrate changes. This provides a potentially highly valuable avenue to influence the competition between PAOs and GAOs. Other VFAs studied seem to be less usable in the short term by both PAOs and GAOs, as indicated by their much lower uptake rates.

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