scholarly journals The spindle assembly checkpoint and speciation

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9073
Author(s):  
Robert C. Jackson ◽  
Hitesh B. Mistry
Keyword(s):  
Related Species ◽  
Spindle Assembly Checkpoint ◽  
Evolutionary Dynamics ◽  
Chromosomal Rearrangements ◽  
Spindle Assembly ◽  
Selective Advantage ◽  
Ecological Niches ◽  
Geographical Isolation ◽  
Closely Related Species ◽  
Definition Of

A mechanism is proposed by which speciation may occur without the need to postulate geographical isolation of the diverging populations. Closely related species that occupy overlapping or adjacent ecological niches often have an almost identical genome but differ by chromosomal rearrangements that result in reproductive isolation. The mitotic spindle assembly checkpoint normally functions to prevent gametes with non-identical karyotypes from forming viable zygotes. Unless gametes from two individuals happen to undergo the same chromosomal rearrangement at the same place and time, a most improbable situation, there has been no satisfactory explanation of how such rearrangements can propagate. Consideration of the dynamics of the spindle assembly checkpoint suggest that chromosomal fission or fusion events may occur that allow formation of viable heterozygotes between the rearranged and parental karyotypes, albeit with decreased fertility. Evolutionary dynamics calculations suggest that if the resulting heterozygous organisms have a selective advantage in an adjoining or overlapping ecological niche from that of the parental strain, despite the reproductive disadvantage of the population carrying the altered karyotype, it may accumulate sufficiently that homozygotes begin to emerge. At this point the reproductive disadvantage of the rearranged karyotype disappears, and a single population has been replaced by two populations that are partially reproductively isolated. This definition of species as populations that differ from other, closely related, species by karyotypic changes is consistent with the classical definition of a species as a population that is capable of interbreeding to produce fertile progeny. Even modest degrees of reproductive impairment of heterozygotes between two related populations may lead to speciation by this mechanism, and geographical isolation is not necessary for the process.

Karyotype Characterisation of Two Australian Dragon Lizards (Squamata: Agamidae: Amphibolurinae) Reveals Subtle Chromosomal Rearrangements Between Related Species with Similar Karyotypes

2020 ◽  
Vol 160 (10) ◽  
pp. 610-624
Author(s):  
Shayer M.I. Alam ◽  
Stephen D. Sarre ◽  
Arthur Georges ◽  
Tariq Ezaz
Keyword(s):  
Sex Chromosomes ◽  
Related Species ◽  
Chromosomal Rearrangements ◽  
In Situ Hybridisation ◽  
Fluorescence In Situ Hybridisation ◽  
Closely Related Species ◽  
Pogona Vitticeps ◽  
Molecular Cytogenetic Techniques ◽  
Heterogametic Sex

Agamid lizards (Squamata: Agamidae) are karyotypically heterogeneous. Among the 101 species currently described from Australia, all are from the subfamily Amphibolurinae. This group is, with some exceptions, karyotypically conserved, and all species involving heterogametic sex show female heterogamety. Here, we describe the chromosomes of 2 additional Australian agamid lizards, <i>Tympanocryptis lineata</i> and <i>Rankinia diemensis</i>. These species are phylogenetically and cytogenetically sisters to the well-characterised <i>Pogona vitticeps,</i> but their sex chromosomes and other chromosomal characteristics are unknown. In this study, we applied advanced molecular cytogenetic techniques, such as fluorescence in situ hybridisation (FISH) and cross-species gene mapping, to characterise chromosomes and to identify sex chromosomes in these species. Our data suggest that both species have a conserved karyotype with <i>P. vitticeps</i> but with subtle rearrangements in the chromosomal landscapes. We could identify that <i>T. lineata</i> possesses a female heterogametic system (ZZ/ZW) with a pair of sex microchromosomes, while <i>R. diemensis</i> may have heterogametic sex chromosomes, but this requires further investigations. Our study shows the pattern of chromosomal rearrangements between closely related species, explaining the speciation within Australian agamid lizards of similar karyotypes.

scholarly journals Evolutionary Dynamics of the Spindle Assembly Checkpoint in Eukaryotes

2020 ◽  
Vol 30 (10) ◽  
pp. R589-R602 ◽  
Author(s):  
Geert J.P.L. Kops ◽  
Berend Snel ◽  
Eelco C. Tromer
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Evolutionary Dynamics ◽  
Spindle Assembly

A reassessment of the genus Haeckeria (Asteraceae: Gnaphalieae), with definition of new species in Cassinia

2004 ◽  
Vol 17 (5) ◽  
pp. 447 ◽  
Author(s):  
A. E. Orchard
Keyword(s):  
New Species ◽  
Leaf Anatomy ◽  
Related Species ◽  
Closely Related Species ◽  
Definition Of

Variation in the species hitherto known as Haeckeria ozothamnoides F.Muell. is discussed. This taxon has well-developed paleae between the florets, and many collections show development of a pappus. These characters, along with others such as leaf anatomy and morphology, strongly distinguish H. ozothamnoides s. lat. from Haeckeria s. str. and place it in Cassinia. The taxon is also shown to comprise three closely related species, which are here described as Cassinia ozothamnoides (F.Muell.) Orchard, comb. nov., C.�scabrida Orchard, sp. nov. and C.�venusta Orchard, sp. nov. The history, taxonomy, relationships and classification of Haeckeria is reviewed, and the genus and its two remaining species, H.�cassiniiformis and H.�punctulata, are described. All five species are illustrated and their distributions mapped.

scholarly journals Recent Insights into Mechanisms of Genome Size Change in Plants

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Corrinne E. Grover ◽  
Jonathan F. Wendel
Keyword(s):  
Genome Size ◽  
Related Species ◽  
Evolutionary Dynamics ◽  
Higher Order ◽  
Size Change ◽  
Closely Related Species ◽  
Genome Size Evolution ◽  
Size Evolution ◽  
Recent Developments

Genome sizes vary considerably across all eukaryotes and even among closely related species. The genesis and evolutionary dynamics of that variation have generated considerable interest, as have the patterns of variation themselves. Here we review recent developments in our understanding of genome size evolution in plants, drawing attention to the higher order processes that can influence the mechanisms generating changing genome size.

scholarly journals Evolutionary dynamics of circular RNAs in primates

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Gabriela Santos-Rodriguez ◽  
Irina Voineagu ◽  
Robert James Weatheritt
Keyword(s):  
Related Species ◽  
Evolutionary Dynamics ◽  
Expression Profiles ◽  
Primate Evolution ◽  
Circular Rnas ◽  
Species Identity ◽  
Closely Related Species ◽  
Tissue Specific ◽  
Organ Type ◽  
Species Specific

Many primate genes produce circular RNAs (circRNAs). However, the extent of circRNA conservation between closely related species remains unclear. By comparing tissue-specific transcriptomes across over 70 million years of primate evolution, we identify that within 3 million years circRNA expression profiles diverged such that they are more related to species identity than organ type. However, our analysis also revealed a subset of circRNAs with conserved neural expression across tens of millions of years of evolution. By comparing to species-specific circRNAs, we identified that the downstream intron of the conserved circRNAs display a dramatic lengthening during evolution due to the insertion of novel retrotransposons. Our work provides comparative analyses of the mechanisms promoting circRNAs to generate increased transcriptomic complexity in primates.

scholarly journals Evolutionary dynamics of circular RNAs in primates

2021 ◽  
Author(s):  
Gabriela Santos-Rodriguez ◽  
Irina Voineagu ◽  
Robert James Weatheritt
Keyword(s):  
Related Species ◽  
Evolutionary Dynamics ◽  
Expression Profiles ◽  
Primate Evolution ◽  
Circular Rnas ◽  
Species Identity ◽  
Closely Related Species ◽  
Tissue Specific ◽  
Comparative Analyses ◽  
Organ Type

Many primate genes produce noncoding circular RNAs (circRNAs). However, the extent of circRNA conservation between closely related species remains unclear. By comparing tissue specific transcriptomes across over 70 million years of primate evolution, we identify that within 3 million years circRNA expression profiles diverged such that they are more related to species identity than organ type. However, our analysis also revealed a subset of circRNAs with conserved neural expression across tens of millions of years of evolution. These circRNAs are defined by an extended downstream intron that has shown dramatic lengthening during evolution due to the insertion of novel retrotransposons. Our work provides comparative analyses of the mechanisms promoting circRNAs to generate increased transcriptomic complexity in primates.

scholarly journals Definition of Plant-Pathogenic Pseudomonas Genomospecies of the Pseudomonas syringae Complex Through Multiple Comparative Approaches

2014 ◽  
Vol 104 (12) ◽  
pp. 1274-1282 ◽  
Author(s):  
Simone Marcelletti ◽  
Marco Scortichini
Keyword(s):  
Pseudomonas Syringae ◽  
Related Species ◽  
Housekeeping Genes ◽  
Bacterial Strains ◽  
Closely Related Species ◽  
Network Analyses ◽  
Taxonomic Relationships ◽  
Pseudomonas Species ◽  
Definition Of ◽  
Phenotypic Tests

A total of 34 phytopathogenic strain genomes belonging to the Pseudomonas syringae species complex and related species, including many pathotype strains, were assessed using average nucleotide identity (ANI) analysis. Their taxonomic relationships were consistently confirmed by the tetranucleotide frequency correlation coefficient (TETRA) values, multilocus sequence typing analysis (MLSA) performed with seven housekeeping genes, using both maximum likelihood and Bayesian methods, and split consensus network analyses. The ANI, MLSA, and split consensus analyses provided consistent and identical results. We confirmed the occurrence of the well-demarcated genomospecies inferred sensu Gardan et al. using DNA-DNA hybridization and ribotyping analyses. However, some P. syringae strains of the pathovars morsprunorum and lachrymans were placed in different genomospecies in our analyses. Genomospecies 1, 2, 4, 6, and 9 resulted well demarcated, whereas strains of genomospecies 3 and 8 had ANI values between 95 and 96% in some cases, confirming that this threshold reveals very closely related species that might represent cases of splitting entities or the convergence of different species to the same ecological niche. This study confirms the robustness of the combination of genomic and phylogenetic approaches in revealing taxonomic relationships among closely related bacterial strains and provides the basis for a further reliable demarcation of the phytopathogenic Pseudomonas species. Within each species, the pathovars might represent distinct ecological units. The possibility of performing extensive and standardized host range and phenotypic tests with many strains of different pathovars can assist phytobacteriologists for better determining the boundaries of these ecological units.

scholarly journals Transposable element dynamics are consistent across the Drosophila phylogeny, despite drastically differing content

2019 ◽  
Author(s):  
Tom Hill
Keyword(s):  
Drosophila Melanogaster ◽  
Related Species ◽  
Evolutionary Dynamics ◽  
Common Ancestor ◽  
Low Frequency ◽  
Fitness Costs ◽  
Closely Related Species ◽  
Drosophila Phylogeny ◽  
Turn Over ◽  
Insertion Frequency

AbstractBackgroundThe evolutionary dynamics of transposable elements (TEs) vary across the tree of life and even between closely related species with similar ecologies. In Drosophila, most of the focus on TE dynamics has been completed in Drosophila melanogaster and the overall pattern indicates that TEs show an excess of low frequency insertions, consistent with their frequent turn over and high fitness cost in the genome. Outside of D. melanogaster, insertions in the species Drosophila algonquin, suggests that this situation may not be universal, even within Drosophila. Here we test whether the pattern observed in D. melanogaster is similar across five Drosophila species that share a common ancestor more than fifty million years ago.ResultsFor the most part, TE family and order insertion frequency patterns are broadly conserved between species, supporting the idea that TEs have invaded species recently, are mostly costly and dynamics are conserved in orthologous regions of the host genomeConclusionsMost TEs retain similar activities and fitness costs across the Drosophila phylogeny, suggesting little evidence of drift in the dynamics of TEs across the phylogeny, and that most TEs have invaded species recently.

scholarly journals Temporal niche partitioning of Swiss black scavenger flies in relation to season and substrate age (Diptera, Sepsidae)

2019 ◽  
Vol 3 ◽  
pp. 1-10 ◽  
Author(s):  
Patrick T. Rohner ◽  
Jean-Paul Haenni ◽  
Athene Giesen ◽  
Juan Pablo Busso ◽  
Martin A. Schäfer ◽  
...  
Keyword(s):  
Related Species ◽  
Species Coexistence ◽  
Species Turnover ◽  
Niche Partitioning ◽  
Temporal Distribution ◽  
Niche Differentiation ◽  
Ecological Niches ◽  
Phylogenetic Distance ◽  
Closely Related Species ◽  
Temporal Niche

Understanding why and how multiple species manage to coexist represents a primary goal of ecological and evolutionary research. This is of particular relevance for communities that depend on resource rich ephemeral habitats that are prone to high intra- and interspecific competition. Black scavenger flies (Diptera: Sepsidae) are common and abundant acalyptrate flies associated with livestock dung decomposition in human-influenced agricultural grasslands worldwide. Several widespread sepsid species with apparently very similar ecological niches coexist in Europe, but despite their ecological role and their use in evolutionary ecological research, our understanding of their ecological niches and spatio-temporal distribution is still rudimentary. To gain a better understanding of their ecology, we here investigate niche partitioning at two temporal scales. First, we monitored the seasonal occurrence, often related to thermal preference, over multiple years and sites in Switzerland that differ in altitude. Secondly, we also investigate fine-scale temporal succession on dairy cow pastures. In accordance with their altitudinal and latitudinal distribution in Europe, some species were common over the entire season with a peak in summer, hence classified as warm-loving, whereas others were primarily present in spring or autumn. Phenological differences thus likely contribute to species coexistence throughout the season. However, the community also showed pronounced species turnover related to cow pat age. Some species colonize particularly fresh dung and are gradually replaced by others. Furthermore, the correlation between co-occurrence and phylogenetic distance of species revealed significant under-dispersion, indicating that more closely related species are frequently recovered at the same location. As a whole, our data suggests temporal niche differentiation of closely related species that likely facilitates the rather high species diversity on Swiss cattle pastures. The underlying mechanisms allowing close relatives to co-occur however require further scrutiny.

scholarly journals Сравнение эколого-климатических ниш двух видов ковылей – Stipa sareptana A.K. Becker и S. krylovii Roshev. (Poaceae)

2017 ◽  
Vol 7 (4) ◽  
pp. 263-269 ◽  
Author(s):  
P. D. Gudkova ◽  
M. V. Olonova ◽  
D. S. Feoktistov
Keyword(s):  
Related Species ◽  
Significant Contribution ◽  
Climatic Conditions ◽  
Ecological Niches ◽  
Mean Annual Temperature ◽  
Morphological Pattern ◽  
Closely Related Species ◽  
The Mean ◽  
Gis Methods ◽  
Subordinate Role

Each species besides of having the unique morphological pattern also has an unique ecologo-climatic niche and geographical range. The study of ecologico-climatic and geographic divergence can make significant contribution to understanding of the species genesis and its volume. The purpose of this paper was to compare the ecologo-climatic niches of the closely related species Stipa sareptana and S. krylovii in order to reveal their identity. The research allowed specifying the areas of both species. Using GIS methods and based on the points of presence and six independent bioclimatic characters, their potential ranges – areas where the climatic conditions are favorable for growth – were identified and ecologo-climatic niches revealed. It was established that the most important factors determining the distribution of S. krylovii and S. sareptana are the mean annual temperature and seasonality of precipitation. Other factors play a subordinate role. The comparison of ecological niches, generated by MaxEnt, showed their differences at a statistically significant level.

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