scholarly journals Uniparental genome elimination in Australian carp gudgeons

2021 ◽  
Author(s):  
Zuzana Majtánová ◽  
Dmitri Dedukh ◽  
Lukáš Choleva ◽  
Mark Adams ◽  
Petr Ráb ◽  
...  
Keyword(s):  
Reproductive Mode ◽  
Chromosome Elimination ◽  
Parental Genome ◽  
Paternal Genome ◽  
Somatic Tissues ◽  
Unique Identity ◽  
Inheritance Mode ◽  
Integral Structure ◽  
Female Hybrid

Abstract Metazoans usually reproduce sexually, blending the unique identity of parental genomes for the next generation through functional crossing-over and recombination in meiosis. However, some metazoan lineages have evolved reproductive systems where offspring are either full (clonal) or partial (hemiclonal) genetic replicas. In the latter group, the process of uniparental genome elimination selectively eliminates either the maternal or paternal genome from germ cells, and only one parental genome is selected for transmission. Although fairly common in plants, hybridogenesis (i.e. clonal haploidization via chromosome elimination) remains a poorly understood process in animals. Here, we explore the proximal cytogenomic mechanisms of somatic and germ cell chromosomes in sexual and hybrid genotypes of Australian carp gudgeons (Hypseleotris) by tracing the fate of each set during mitosis (in somatic tissues) and meiosis (in gonads). Our comparative study of diploid hybrid and sexual individuals revealed visually functional gonads in male and female hybrid genotypes and generally high karyotype variability, although the number of chromosome arms remains constant. Our results delivered direct evidence for classic hybridogenesis as a reproductive mode in carp gudgeons. Two parental sets with integral structure in the hybrid soma (the F1 constitution) contrasted with uniparental chromosomal inheritance detected in gonads. The inheritance mode happens through pre-meiotic genome duplication of the parental genome to be transmitted, while the second parental genome is likely gradually eliminated already in juvenile individuals. The role of metacentric chromosomes in hybrid evolution is also discussed.

scholarly journals Profound genetic divergence and asymmetric parental genome contributions as hallmarks of hybrid speciation in polyploid toads

2018 ◽  
Vol 285 (1872) ◽  
pp. 20172667 ◽  
Author(s):  
Caroline Betto-Colliard ◽  
Sylvia Hofmann ◽  
Roberto Sermier ◽  
Nicolas Perrin ◽  
Matthias Stöck
Keyword(s):  
Parental Species ◽  
Reproductive Mode ◽  
The Other ◽  
Secondary Contact ◽  
Hybrid Speciation ◽  
Parental Genome ◽  
Paternal Genome ◽  
Ploidy Levels ◽  
Genomic Imbalance ◽  
Green Toad

The evolutionary causes and consequences of allopolyploidization, an exceptional pathway to instant hybrid speciation, are poorly investigated in animals. In particular, when and why hybrid polyploids versus diploids are produced, and constraints on sources of paternal and maternal ancestors, remain underexplored. Using the Palearctic green toad radiation (including bisexually reproducing species of three ploidy levels) as model, we generate a range-wide multi-locus phylogeny of 15 taxa and present four new insights: (i) at least five (up to seven) distinct allotriploid and allotetraploid taxa have evolved in the Pleistocene; (ii) all maternal and paternal ancestors of hybrid polyploids stem from two deeply diverged nuclear clades (6 Mya, 3.1–9.6 Mya), with distinctly greater divergence than the parental species of diploid hybrids found at secondary contact zones; (iii) allotriploid taxa possess two conspecific genomes and a deeply diverged allospecific one, suggesting that genomic imbalance and divergence are causal for their partly clonal reproductive mode; (iv) maternal versus paternal genome contributions exhibit asymmetry, with the maternal nuclear (and mitochondrial) genome of polyploids always coming from the same clade, and the paternal genome from the other. We compare our findings with similar patterns in diploid/polyploid vertebrates, and suggest deep ancestral divergence as a precondition for successful allopolyploidization.

On the role of germ cells in planarian regeneration

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 53-63
Author(s):  
V. Gremigni ◽  
C. Miceli ◽  
I. Puccinelli
Keyword(s):  
Chromosome Number ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Karyological Analysis ◽  
Blastema Formation ◽  
Planarian Regeneration ◽  
Somatic Tissues ◽  
Caudal Area ◽  
Complete Regeneration

Specimens from a polyploid biotype of Dugesia lugubris s.l. were used to clarify the role and fate of germ cells during planarian regeneration. These specimens provide a useful karyological marker because embryonic and somatic cells (3n = 12) can be easily distinguished from male (2n = 8) and female (6n = 24) germ cells by their chromosome number. We succeed in demonstrating how primordial germ cells participate in blastema formation and take part in rebuilding somatic tissues. This evidence was obtained by cutting each planarian specimen twice at appropriate levels. The first aimed to induce primordial germ cells to migrate to the wound. The second cut was performed after complete regeneration and aimed to obtain a blastema from a cephalic or caudal area devoid of gonads. A karyological analysis of mitotic cells present in each blastema obtained after the second cut provided evidence that cells, originally belonging to the germ lines, are still present in somatic tissues even months after complete regeneration. The role of primordial germ cells in planarian regeneration was finally discussed in relation to the phenomenon of metaplasia or transdifferentiation.

scholarly journals Successive specification of Drosophila neuroblasts NB 6-4 and NB 7-3 depends on interaction of the segment polarity genes wingless, gooseberry and naked cuticle

Development ◽  
2001 ◽  
Vol 128 (17) ◽  
pp. 3253-3261 ◽  
Author(s):  
Nirupama Deshpande ◽  
Rainer Dittrich ◽  
Gerhard M. Technau ◽  
Joachim Urban
Keyword(s):  
Cell Fate ◽  
Cell Lineage ◽  
Positional Information ◽  
Dorsoventral Patterning ◽  
Expression Domain ◽  
Direct Role ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Unique Identity

The Drosophila central nervous system derives from neural precursor cells, the neuroblasts (NBs), which are born from the neuroectoderm by the process of delamination. Each NB has a unique identity, which is revealed by the production of a characteristic cell lineage and a specific set of molecular markers it expresses. These NBs delaminate at different but reproducible time points during neurogenesis (S1-S5) and it has been shown for early delaminating NBs (S1/S2) that their identities depend on positional information conferred by segment polarity genes and dorsoventral patterning genes. We have studied mechanisms leading to the fate specification of a set of late delaminating neuroblasts, NB 6-4 and NB 7-3, both of which arise from the engrailed (en) expression domain, with NB 6-4 delaminating first. In contrast to former reports, we did not find any evidence for a direct role of hedgehog in the process of NB 7-3 specification. Instead, we present evidence to show that the interplay of the segmentation genes naked cuticle (nkd) and gooseberry (gsb), both of which are targets of wingless (wg) activity, leads to differential commitment to NB 6-4 and NB 7-3 cell fate. In the absence of either nkd or gsb, one NB fate is replaced by the other. However, the temporal sequence of delamination is maintained, suggesting that formation and specification of these two NBs are under independent control.

Evaluating Change in Housing for Sustainable Development: Kosuyolu Case in Istanbul

2015 ◽  
Vol 40 (4) ◽  
pp. 55-62
Author(s):  
Dilek Yildiz
Keyword(s):  
Sustainable Development ◽  
Structured Interviews ◽  
Land Use Pattern ◽  
The Sustainable Development ◽  
Urban Dynamics ◽  
Unique Identity ◽  
Historic Memory ◽  
Alternative Scenarios

Sparse attention has been paid to the inevitable processes of change that enable progress in today's globalizing urban centres, but also threaten their unique identity, historic memory, and cultural heritage. The aims of this work are to understand the urban dynamics that trigger these change processes, uncover their effects, and discuss how these changes can be utilized to achieve sustainable development. The case study, which uses a comparative mixed method strategy consisting of archival research, fieldwork, and semi-structured interviews, is the Kosuyolu Housing Settlement, a project dating to the 1950s that represents one of Istanbul's best examples of urban development and housing culture. Displaying the architectural and urban planning ideals of the Modern period, this settlement is a concrete example that reflects the period's considerations regarding social housing. Through this case, change in housing has been evaluated in terms of sustainability indicators. The derived evidences show the significant role of governance and the maintained land use pattern for the achievement of the sustainable development and these evidences are used to suggest the development of an adaption guide that will assist in sustainable development in the short term, and the creation of alternative scenarios that are flexible and easy to adapt, active, and based on participatory processes for the long term.

Role of microtubules and microtubule organizing centers on meiotic chromosome elimination in Sciara ocellaris

1997 ◽  
Vol 110 (6) ◽  
pp. 721-730 ◽  
Author(s):  
M.R. Esteban ◽  
M.C. Campos ◽  
A.L. Perondini ◽  
C. Goday
Keyword(s):  
Meiotic Chromosome ◽  
Chromosome Elimination ◽  
Male Meiosis ◽  
Meiotic Spindle ◽  
Monopolar Spindle ◽  
Meiotic Spindles ◽  
Cytoplasmic Microtubules ◽  
Spindle Microtubules ◽  
Meiosis I

Spindle formation and chromosome elimination during male meiosis in Sciara ocellaris (Diptera, Sciaridae) has been studied by immunofluorescence techniques. During meiosis I a monopolar spindle is formed from a single polar complex (centrosome-like structure). This single centrosomal structure persists during meiosis II and is responsible for the non-disjunction of the maternal X chromatids. During meiosis I and II non-spindle microtubules are assembled in the cytoplasmic bud regions of the spermatocytes. The chromosomes undergoing elimination during both meiotic divisions are segregated to the bud region where they associate with bundles of microtubules. The presence and distribution of centrosomal antigens in S. ocellaris meiotic spindles and bud regions has been investigated using different antibodies. gamma-Tubulin and centrin are present in the bud as well as in the single polar complex of first meiotic spindle. The results suggest that spermatocyte bud regions contain microtubule-organizing centres (MTOCs) that nucleate cytoplasmic microtubules that are involved in capturing chromosomes in the bud regions. The distribution of actin and myosin in the spermatocytes during meiosis is also reported.

scholarly journals Transmission efficiency drives host–microbe associations

2020 ◽  
Vol 287 (1934) ◽  
pp. 20200820 ◽  
Author(s):  
Philip T. Leftwich ◽  
Matthew P. Edgington ◽  
Tracey Chapman
Keyword(s):  
Mate Choice ◽  
Reproductive Mode ◽  
Transmission Efficiency ◽  
Evolutionary Significance ◽  
Minimal Impact ◽  
Animal Host ◽  
Host Fitness ◽  
Modes Of Transmission ◽  
Sequencing Technologies

Sequencing technologies have fuelled a rapid rise in descriptions of microbial communities associated with hosts, but what is often harder to ascertain is the evolutionary significance of these symbioses. Here, we review the role of vertical (VT), horizontal (HT), environmental acquisition and mixed modes of transmission (MMT), in the establishment of animal host–microbe associations. We then model four properties of gut microbiota proposed as key to promoting animal host–microbe relationships: modes of transmission, host reproductive mode, host mate choice and host fitness. We found that: (i) MMT led to the highest frequencies of host–microbe associations, and that some environmental acquisition or HT of microbes was required for persistent associations to form unless VT was perfect; (ii) host reproductive mode (sexual versus asexual) and host mate choice (for microbe carriers versus non-carriers) had little impact on the establishment of host–microbe associations; (iii) host mate choice did not itself lead to reproductive isolation, but could reinforce it; and (iv) changes in host fitness due to host–microbe associations had a minimal impact upon the formation of co-associations. When we introduced a second population, into which host–microbe carriers could disperse but in which environmental acquisition did not occur, highly efficient VT was required for host–microbe co-associations to persist. Our study reveals that transmission mode is of key importance in establishing host–microbe associations.

scholarly journals The role of the paternal genome in the development of the mouse germ line

1997 ◽  
Vol 7 (11) ◽  
pp. 881-884 ◽  
Author(s):  
Maithreyi Narasimha ◽  
Sheila C. Barton ◽  
M.Azim Surani
Keyword(s):  
Germ Line ◽  
Paternal Genome

scholarly journals Mother-offspring conflict for water and its mitigation in the oviparous form of the reproductively bimodal lizard, Zootoca vivipara

2020 ◽  
Vol 129 (4) ◽  
pp. 888-900
Author(s):  
Andréaz Dupoué ◽  
Mahaut Sorlin ◽  
Murielle Richard ◽  
Jean François Le Galliard ◽  
Olivier Lourdais ◽  
...  
Keyword(s):  
Reproductive Mode ◽  
Development Stage ◽  
Water Restriction ◽  
Treatment Timing ◽  
Common Lizard ◽  
Zootoca Vivipara ◽  
Gravid Females ◽  
The Impact

Abstract Parent-offspring conflicts are widespread given that resources are often limited. Recent evidence has shown that availability of water can trigger such conflict during pregnancy in viviparous squamate species (lizards and snakes) and thus questions the role of water in the evolution of reproductive modes. Here, we examined the impact of water restriction during gravidity in the oviparous form of the bimodal common lizard (Zootoca vivipara), using a protocol previously used on the viviparous form. Females were captured in early gravidity from six populations along a 600 m altitudinal gradient to investigate whether environmental conditions (altitude, water access and temperature) exacerbate responses to water restriction. Females were significantly dehydrated after water restriction, irrespective of their reproductive status (gravid vs. non-reproductive), relative reproductive effort (relative clutch mass), and treatment timing (embryonic development stage). Female dehydration, together with reproductive performance, varied with altitude, probably due to long term acclimation or local adaptation. This moderate water-based intergenerational conflict in gravid females contrasts sharply with previous findings for the viviparous form, with implications to the evolutionary reversion from viviparity to oviparity. It is likely that oviparity constitutes a water-saving reproductive mode which might help mitigate intensive temperature-driven population extinctions at low altitudes.

The distribution of male-transmitted and female-transmitted mitochondrial DNA types in somatic tissues of blue mussels: Implications for the operation of doubly uniparental inheritance of mitochondrial DNA

Genome ◽  
1998 ◽  
Vol 41 (6) ◽  
pp. 818-824 ◽  
Author(s):  
Manuel A Garrido-Ramos ◽  
Donald T Stewart ◽  
Brent W Sutherland ◽  
Eleftherios Zouros
Keyword(s):  
Mitochondrial Dna ◽  
Blue Mussel ◽  
Uniparental Inheritance ◽  
Doubly Uniparental Inheritance ◽  
Dominant Type ◽  
Blue Mussels ◽  
Somatic Tissues ◽  
Dna Types ◽  
M Genome

We have examined the mitochondrial DNA (mtDNA) content of several somatic tissues from male and female individuals of the blue mussel, Mytilus edulis. As expected from the mode of doubly uniparental inheritance (DUI) of mtDNA that is characteristic of this genus, the dominant type of mtDNA in male gonads was the male-transmitted M type. In contrast, all male somatic tissues were dominated by the female-transmitted F type. The M type could occasionally be detected in one or another tissue of a few female individuals. The findings have several implications for the operation of doubly uniparental inheritance of mitochondrial DNA, among which the most important are (i) the M genome does not have an unconditional replicative advantage over the F genome, and (ii) in contrast to "masculinization" (the process by which an F molecule assumes the role of the M genome) "feminization" (the process by which an M molecule assumes the role of the F genome) might be a rare but not impossible phenomenon.Key words: mitochondrial DNA inheritance, mitochondrial DNA tissue distribution, blue mussels, gender-specific mtDNA, doubly uniparental inheritance of mtDNA, Mytilus.

Telomerase: A Potential Diagnostic and Therapeutic Tool in Canine Oncology

2003 ◽  
Vol 40 (1) ◽  
pp. 1-7 ◽  
Author(s):  
D. J. Argyle ◽  
L. Nasir
Keyword(s):  
Human Cancer ◽  
Biological Significance ◽  
Telomerase Activity ◽  
Clinical Implications ◽  
Therapeutic Tool ◽  
Vast Number ◽  
Somatic Tissues ◽  
Canine Tumors ◽  
Cancer Tissues

In recent years there has been considerable interest in telomerase as a target for therapeutic intervention in oncology. This largely stems from the vast number of studies that have demonstrated expression and activity of the enzyme telomerase in the majority of human cancer tissues with little or no activity detectable in normal somatic tissues. These studies have led to an interest in the role of telomerase in cancers associated with domesticated species, in particular tumors that affect dogs. This article reviews the biology of telomerase and the biological significance of telomerase activity in canine tumors and discusses the clinical implications of telomerase expression in canine cancers with regard to therapeutics and diagnostics.

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