scholarly journals Identification of Parental Genome Construction and Inherited Morphological Characteristics in Triploid and AneuploidIntergeneric Hybrids from a Diploid−Diploid Cross between Citrus and Fortunella

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1988
Author(s):  
Kiichi Yasuda ◽  
Masaki Yahata ◽  
Mai Sato ◽  
Miki Sudo ◽  
Akiyoshi Tominaga ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Intergeneric Hybrids ◽  
Unreduced Gametes ◽  
Unreduced Gamete ◽  
Parental Genome ◽  
Chromomycin A3 ◽  
Horticultural Traits ◽  
Ssr Genotyping ◽  
Intermediate Traits

We previously obtained two intergeneric hybrids with different ploidies, i.e., aneuploid (2n = 28) and eutriploid, from diploid−diploid crosses between ‘Kiyomi’ tangor (Citrus unshiu Marcow. × C. sinensis (L.) Osbeck) and Meiwa kumquat (Fortunella crassifolia Swingle) as novel breeding materials for a seedless kumquat. In this study, we attempted to clarify the construction of the parental genomes of these hybrids by SSR genotyping and genomic in situ hybridization (GISH)−chromomycin A3 (CMA) analysis. SSR genotyping in NSX43 (LG5) and CiBE2227 (LG8) loci revealed that both hybrids inherited one allele from ‘Kiyomi’ tangor and two heterozygous alleles from Meiwa kumquat. The GISH analysis failed due to the high genomic homology between Citrus and Fortunella. At the same time, the CMA karyotype compositions of the two intergeneric hybrids (H15-701: 2A + 1B + 3C + 13D + 7E + 1F + 1Dst; H15-702: 3A + 1B + 2C + 15D + 4E +1F + 1Dst) and both parents (‘Kiyomi’ tangor: 1A + 2B + 2C + 6D + 7E; Meiwa kumquat: 2A + 2C + 12D + 1F + 1Dst) were completely revealed. We identified the parental genome construction and polyploidization processes in both intergeneric hybrids on the basis of these SSR genotypes and CMA karyotype compositions according to the following theory: the SSR genotypes and chromosome compositions were the same as those of the somatic chromosome and two-fold after the first division (even number) in unreduced gametes caused by first-division restitution (FDR) and second-division restitution (SDR), respectively. Consequently, we determined that both intergeneric hybrids may have had two genomes derived from the 2n male unreduced gamete as a result of the FDR of the Meiwa kumquat. In addition, most horticultural traits of the leaves, flowers, and fruits of both hybrids showed intermediate traits of the parents, but the fruit sizes and flowering habits were more like those of the two inherited genomes of Meiwa kumquat.

scholarly journals Asynapsis and unreduced gamete formation in a Trifolium interspecific hybrid

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Helal A. Ansari ◽  
Nicholas W. Ellison ◽  
Isabelle M. Verry ◽  
Warren M. Williams
Keyword(s):  
Meiotic Division ◽  
High Frequency ◽  
Molecular Mechanisms ◽  
Intergeneric Hybrids ◽  
Unreduced Gametes ◽  
Unreduced Gamete ◽  
Sister Chromatids ◽  
Gamete Formation ◽  
Normal Meiosis ◽  
Metaphase I

Abstract Background Unreduced gametes, a driving force in the widespread polyploidization and speciation of flowering plants, occur relatively frequently in interspecific or intergeneric hybrids. Studies of the mechanisms leading to 2n gamete formation, mainly in the wheat tribe Triticeae have shown that unreductional meiosis is often associated with chromosome asynapsis during the first meiotic division. The present study explored the mechanisms of meiotic nonreduction leading to functional unreduced gametes in an interspecific Trifolium (clover) hybrid with three sub-genomes from T. ambiguum and one sub-genome from T. occidentale. Results Unreductional meiosis leading to 2n gametes occurred when there was a high frequency of asynapsis during the first meiotic division. In this hybrid, approximately 39% of chromosomes were unpaired at metaphase I. Within the same cell at anaphase I, sister chromatids of univalents underwent precocious separation and formed laggard chromatids whereas paired chromosomes segregated without separation of sister chromatids as in normal meiosis. This asynchrony was frequently accompanied by incomplete or no movement of chromosomes toward the poles and restitution leading to unreduced chromosome constitutions. Reductional meiosis was restored in progeny where asynapsis frequencies were low. Two progeny plants with approximately 5 and 7% of unpaired chromosomes at metaphase I showed full restoration of reductional meiosis. Conclusions The study revealed that formation of 2n gametes occurred when asynapsis (univalent) frequency at meiosis I was high, and that normal gamete production was restored in the next generation when asynapsis frequencies were low. Asynapsis-dependent 2n gamete formation, previously supported by evidence largely from wheat and its relatives and grasshopper, is also applicable to hybrids from the dicotyledonous plant genus Trifolium. The present results align well with those from these widely divergent organisms and strongly suggest common molecular mechanisms involved in unreduced gamete formation.

Alteration of chromosome behavior and synchronization of parental chromosomes after successive generations in Brassica napus × Orychophragmus violaceus hybrids

Genome ◽  
2007 ◽  
Vol 50 (2) ◽  
pp. 226-233 ◽  
Author(s):  
Zhigang Zhao ◽  
Ni Ma ◽  
Zaiyun Li
Keyword(s):  
Brassica Napus ◽  
Meiotic Division ◽  
Morphological Characteristics ◽  
Intergeneric Hybrids ◽  
Orychophragmus Violaceus ◽  
Genome Separation ◽  
Cytogenetic Evidence ◽  
Successive Generations ◽  
Mother Cells

In an earlier study, the progenies of intergeneric hybrids Brassica napus (2n = 38) × Orychophragmus violaceus (2n = 24) were investigated in successive generations (F1–F4) for the cytological phenomenon of parental genome separation during mitotic and meiotic division. In the present study, inbred lines (F5–F8) derived from 1 such hybrid were characterized for morphology, chromosome pairing behaviour, and genome composition. One F5 plant (2n = 31) with slightly yellow petals and 12:19 and 15:16 segregation ratios in its pollen mother cells (PMCs) produced F6 plants with distinct morphological characteristics and wide variations in fertility and chromosome numbers (2n = 25–38). F7 and F8 lines with distinctive morphology and wide ranges in chromsome numbers were established. In PMCs of F7 plants from 4 F6 plants, 0–12 labelled chromosomes from O. violaceus, which predominantly appeared as bivalents, were identified by genomic in situ hybridization. They behaved synchronously with B. napus chromosomes during meiotic division. The results provide molecular cytogenetic evidence of the inclusion of O. violaceus chromosomes in the original hybrids and the cytology in the hybrids documented earlier. They also show that chromosome behaviour was altered and the parental chromosomes became synchronized after successive generations.

scholarly journals Radiomorphology of the Habib Sealer-Induced Resection Plane during Long-Time Followup:A Longitudinal Single Center Experience after 64 Radiofrequency-AssistedLiver Resections

HPB Surgery ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Robert Kleinert ◽  
Roger Wahba ◽  
Christoph Bangard ◽  
Klaus Prenzel ◽  
Arnulf H. Hölscher ◽  
...  
Keyword(s):  
Liver Resection ◽  
Morphological Characteristics ◽  
Postoperative Mortality ◽  
Coagulation Necrosis ◽  
Time Interval ◽  
Safe Alternative ◽  
Time Points ◽  
Single Center Experience ◽  
Long Time

Background. Radiofrequency (RF-) assisted liver resection devices like the Habib sealer induce a necrotic resection plane from which a small margin of necrotic liver tissue remains in situ. The aim of the present paper was to report our long-time experience with the new resection method and the morphological characteristics of the remaining necrotic resection plane. Methods. 64 RF-assisted liver resections were performed using the Habib sealer. Followup was assessed at defined time points. Results. The postoperative mortality was 3,6% and morbidity was 18%. The followup revealed that the necrotic zone was detectable in all analyzed CT and MRI images as a hypodense structure without any contrast enhancement at all time points, irrespectively of the time interval between resection and examination. Conclusion. Liver resection utilizing radiofrequency-induced resection plane coagulation is a safe alternative to the established resection techniques. The residual zone of coagulation necrosis remains basically unchanged during a followup of three years. This has to be kept in mind when evaluating the follow up imaging of these patients.

scholarly journals A new method to detect apoptosis in paraffin sections: in situ end-labeling of fragmented DNA.

1993 ◽  
Vol 41 (1) ◽  
pp. 7-12 ◽  
Author(s):  
J H Wijsman ◽  
R R Jonker ◽  
R Keijzer ◽  
C J van de Velde ◽  
C J Cornelisse ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Staining Method ◽  
Morphological Characteristics ◽  
Image Cytometry ◽  
Apoptotic Cells ◽  
Dna Breaks ◽  
Paraffin Sections ◽  
Tissue Sections

Apoptosis (programmed cell death) can be difficult to detect in routine histological sections. Since extensive DNA fragmentation is an important characteristic of this process, visualization of DNA breaks could greatly facilitate the identification of apoptotic cells. We describe a new staining method for formalin-fixed, paraffin-embedded tissue sections that involves an in situ end-labeling (ISEL) procedure. After protease treatment to permeate the tissue sections, biotinylated nucleotides are in situ incorporated into DNA breaks by polymerase and subsequently stained with DAB via peroxidase-conjugated avidin. Staining of cells with the morphological characteristics of apoptosis was demonstrated in tissues known to exhibit programmed cell death, i.e., prostate and uterus after castration, tumors, lymph node follicles, and embryos. Apoptotic cells could be discriminated morphologically from areas of labeled necrotic cells, in which DNA degradation also occurs. Because apoptosis is relatively easily recognized in H&E-stained sections of involuting prostates of castrated rats, we used this model system to validate the ISEL method for the quantification of apoptotic cells. A high correlation was found between the fractions of ISEL-labeled cells and the fractions of apoptotic cells that were morphologically determined in adjacent sections. We conclude that ISEL is a useful technique for quantification of apoptosis in paraffin sections, especially for those tissues in which morphological determination is difficult. Furthermore, this new staining method enables the use of automated image cytometry for evaluating apoptosis.

scholarly journals ELECTROCHEMICAL OXIDATION OF ETHANOL USING Ni-Co-PVC COMPOSITE ELECTRODE

2011 ◽  
Vol 11 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Riyanto Riyanto ◽  
Mohamed Rozali Othman ◽  
Jumat Salimon
Keyword(s):  
Polyvinyl Chloride ◽  
Electrochemical Behavior ◽  
Morphological Characteristics ◽  
Redox System ◽  
Electrochemical Technique ◽  
Metal Foil ◽  
Composite Electrodes ◽  
Nickel Metal ◽  
Nickel Cobalt

The morphological characteristics and electrochemical behavior of nickel metal foil (Ni), nickel-polyvinyl chloride (Ni-PVC) and nickel-cobalt-polyvinyl chloride (Ni-Co-PVC) electrodes in alkaline solution has been investigated. The morphological characteristics of the electrode surface were studied using SEM and EDS, while the electrochemical behavior of the electrodes was studied using cyclic voltammetry (CV). It was found that composite electrodes (Ni-PVC and Ni-Co-PVC) have a porous, irregular and rough surface. In situ studies using electrochemical technique using those three electrodes exhibited electrochemical activity for redox system, as well as selectivity in the electrooxidation of ethanol to acetic acid. The studies also found that an electrokinetics and electrocatalytic activity behaviors of the electrodes prepared were Ni metal foil

scholarly journals Ploidy frequencies in plants with ploidy heterogeneity: fitting a general gametic model to empirical population data

2013 ◽  
Vol 280 (1751) ◽  
pp. 20122387 ◽  
Author(s):  
Jan Suda ◽  
Tomáš Herben
Keyword(s):  
Natural Populations ◽  
Evolutionary Process ◽  
Optimization Procedure ◽  
Population Data ◽  
Unreduced Gametes ◽  
Unreduced Gamete ◽  
Model Parameters ◽  
Main Mode ◽  
Ploidy Levels ◽  
Polyploid Formation

Genome duplication (polyploidy) is a recurrent evolutionary process in plants, often conferring instant reproductive isolation and thus potentially leading to speciation. Outcome of the process is often seen in the field as different cytotypes co-occur in many plant populations. Failure of meiotic reduction during gametogenesis is widely acknowledged to be the main mode of polyploid formation. To get insight into its role in the dynamics of polyploidy generation under natural conditions, and coexistence of several ploidy levels, we developed a general gametic model for diploid–polyploid systems. This model predicts equilibrium ploidy frequencies as functions of several parameters, namely the unreduced gamete proportions and fertilities of higher ploidy plants. We used data on field ploidy frequencies for 39 presumably autopolyploid plant species/populations to infer numerical values of the model parameters (either analytically or using an optimization procedure). With the exception of a few species, the model fit was very high. The estimated proportions of unreduced gametes (median of 0.0089) matched published estimates well. Our results imply that conditions for cytotype coexistence in natural populations are likely to be less restrictive than previously assumed. In addition, rather simple models show sufficiently rich behaviour to explain the prevalence of polyploids among flowering plants.

A Monumental Horse Burial in the Armenian Highlands

2021 ◽  
Vol 49 (3) ◽  
pp. 41-50
Author(s):  
A. Nachmias ◽  
G. Bar-Oz ◽  
D. Nadel ◽  
I. Petrosyan ◽  
B. Gasparyan
Keyword(s):  
Morphological Characteristics ◽  
Radiometric Dating ◽  
Large Individual ◽  
Metal Ring ◽  
Tall Stature ◽  
Unique Combination ◽  
The Past

Here we report on the unprecedented discovery of the complete skeleton of a ritually interred adult stallion with a bronze ring in its mouth. The horse was buried in a unique 15-meters diameter monumental stone-built tomb excavated in the Aghavnatun necropolis located on the southern slopes of Mt. Aragats, in the northern fringes of the Ararat Depression, Republic of Armenia. The tumulus was roughly circular; the horse’s remains were found in situ, in an inner oval-shaped structure. Our methodological procedure included a detailed description of the burial, a taphonomic study of the bones, and meticulous morphometric observations and measurements, and thus we could provide a taxonomic defi nition and an age estimate. Direct radiometric dating of the horse’s skeleton provided a date of 2130±20 BP. The morphological characteristics of the horse, with its tall stature and slender feet, suggest that it was a large individual, similar to the extinct breed of Nisean horse previously known mainly from textual and iconographical sources. The metal ring found in the mouth of the horse suggests that it likely served as a breeding stallion. This discovery presents a unique combination of zooarchaeological evidence for the importance of the horse in the Parthian-Hellenistic worlds, and advances our understanding of the broad social signifi cance of the past breeding of equids in the Armenian Highlands.

scholarly journals Transcriptome Analysis of Young Ovaries Reveals Candidate Genes Involved in Gamete Formation in Lantana camara

Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 263 ◽  
Author(s):  
Ze Peng ◽  
Krishna Bhattarai ◽  
Saroj Parajuli ◽  
Zhe Cao ◽  
Zhanao Deng
Keyword(s):  
Candidate Genes ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Gene Families ◽  
Unreduced Gametes ◽  
Lantana Camara ◽  
Unreduced Gamete ◽  
Genomic Resources ◽  
Gamete Formation ◽  
Gamete Production

Lantana (Lantana camara L., Verbenaceae) is an important ornamental crop, yet can be a highly invasive species. The formation of unreduced female gametes (UFGs) is a major factor contributing to its invasiveness and has severely hindered the development of sterile cultivars. To enrich the genomic resources and gain insight into the genetic mechanisms of UFG formation in lantana, we investigated the transcriptomes of young ovaries of two lantana genotypes, GDGHOP-36 (GGO), producing 100% UFGs, and a cultivar Landmark White Lantana (LWL), not producing UFGs. The de novo transcriptome assembly resulted in a total of 90,641 unique transcript sequences with an N50 of 1692 bp, among which, 29,383 sequences contained full-length coding sequences (CDS). There were 214 transcripts associated with the biological processes of gamete production and 10 gene families orthologous to genes known to control unreduced gamete production in Arabidopsis. We identified 925 transcription factor (TF)-encoding sequences, 91 nucleotide-binding site (NBS)-containing genes, and gene families related to drought/salt tolerance and allelopathy. These genomic resources and candidate genes involved in gamete formation will be valuable for developing new tools to control the invasiveness in L. camara, protect native lantana species, and understand the formation of unreduced gametes in plants.

Development and characterization of Triticum turgidum – Aegilops comosa and T. turgidum – Ae. markgrafii amphidiploids

Genome ◽  
2020 ◽  
Vol 63 (5) ◽  
pp. 263-273
Author(s):  
Yuanyuan Zuo ◽  
Qin Xiang ◽  
Shoufen Dai ◽  
Zhongping Song ◽  
Tingyu Bao ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Diploid Species ◽  
Unreduced Gametes ◽  
Stripe Rust Resistance ◽  
Aegilops Comosa ◽  
Direct Hybridization

Aegilops comosa and Ae. markgrafii are diploid progenitors of polyploidy species of Aegilops sharing M and C genomes, respectively. Transferring valuable genes/traits from Aegilops into wheat is an alternative strategy for wheat genetic improvement. The amphidiploids between diploid species of Aegilops and tetraploid wheat can act as bridges to overcome obstacles from direct hybridization and can be developed by the union of unreduced gametes. In this study, we developed seven Triticum turgidum – Ae. comosa and two T. turgidum – Ae. markgrafii amphidiploids. The unreduced gametes mechanisms, including first-division restitution (FDR) and single-division meiosis (SDM), were observed in triploid F1 hybrids of T. turgidum – Ae. comosa (STM) and T. turgidum – Ae. markgrafii (STC). Only FDR was observed in STC hybrids, whereas FDR or both FDR and SDM were detected in the STM hybrids. All seven pairs of M chromosomes of Ae. comosa and C chromosomes of Ae. markgrafii were distinguished by fluorescent in situ hybridization (FISH) probes pSc119.2 and pTa71 combinations with pTa-535 and (CTT)12/(ACT)7, respectively. Meanwhile, the chromosomes of tetraploid wheat and diploid Aegilops parents were distinguished by the same FISH probes. The amphidiploids possessed specific valuable traits such as multiple tillers, large seed size related traits, and stripe rust resistance that could be utilized in the genetic improvement of wheat.

Coenocytism, ameiosis, and chromosome diminution in intergeneric hybrids in the perennial Triticeae

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 766-775 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Intergeneric Hybrid ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Pollen Grain ◽  
Unreduced Gamete ◽  
Pollen Mother Cells ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Mother Cells ◽  
Pollen Grain Wall

Three different pathways of ameiotic microsporogenesis were observed in some intergeneric hybrids of the perennial Triticeae grasses. In one of the hybrids between Pseudoroegneria spicata ssp. inermis and Psathyrostachys juncea, pollen mother cells remained as premeiotic interphase cells when the pollen grain wall started to form. The microspores in such an ameiotic plant are presumably unreduced. Coenocyte formation coupled with ameiosis occurred in two hybrid plants of Psathyrostachys huashanica × Secale montanum. Less than 10% of the pollen mother cells had one nucleus. An average of 4.44 nuclei, ranging from 1 to 25 per pollen mother cell, was observed. The nuclei in coenocytes remained unfused when the pollen grain wall was formed. Nucleus splitting followed by cytoplasmic budding or cleavage, possibly a process of chromosome diminution or elimination, replaced meiotic divisions in most of the pollen mother cells in one plant of Leymus angustus × Hordeum bulbosum and two plants of Thinopyrum elongatum × Psathyrostachys juncea. It is evident that these meiotic abnormalities are under genetic control. Probable locations for these genes controlling these phenomena are suggested.Key words: coenocyte, ameiosis, chromosome diminution, chromosome elimination, microsporogenesis, unreduced gamete, polyploidy, intergeneric hybrid.

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