EVOLUTIONARY ORIGIN OF POA ANNUA L. IN THE LIGHT OF KARYOTYPIC STUDIES

1968 ◽  
Vol 10 (1) ◽  
pp. 112-118 ◽  
Author(s):  
T. K. Koshy
Keyword(s):  
Evolutionary History ◽  
Karyotype Analysis ◽  
Diploid Species ◽  
Small Chromosome ◽  
Evolutionary Origin ◽  
Poa Annua ◽  
History Of ◽  
Unidentified Species ◽  
Poa Supina

From a karyotype analysis of Poa annua (2n = 28) two large chromosomes, I and II, and one small chromosome, XIV, as well as three chromosome groups containing two, four and five chromosomes have been identified. From a comparison of the karyotype of Poa annua with that published of Poa exilis (2n = 14) and Poa supina (2n = 14), doubt is cast on the theory that Poa annua is an allotetraploid of the two latter diploid species. The three chromosomes of Poa annua that could be identified with certainty existed in homologous pairs, indicating that the species could have originated from Poa exilis or Poa supina and one other hitherto unidentified species. It is suggested that further work on the karyotype of diploid species might reveal further useful information on the evolutionary history of the species.

scholarly journals Insights on the process of reciprocal gene loss in the duplicate DPL genes of rice

2019 ◽  
Author(s):  
Xun Xu ◽  
Song Ge ◽  
Fu-min Zhang
Keyword(s):  
Evolutionary History ◽  
Gene Loss ◽  
Diploid Species ◽  
Recent Common Ancestor ◽  
Duplicate Genes ◽  
Evolutionary Divergence ◽  
Dna Transposons ◽  
B Genome ◽  
A Genome ◽  
History Of

Abstract Background: Reciprocal gene loss (RGL) of duplicate genes is an important genetic resource of reproductive isolation, which is essential for speciation. In the past decades, various RGL patterns have been revealed, but RGL process is still poorly understood. The RGL of the duplicate DOPPELGANGER1 (DPL1) and DOPPELGANGER2 (DPL2) gene can lead to BDM-type hybrid incompatibility between two rice subspecies. The evolutionary history of the duplicate genes, including their origin and mechanism of duplication as well as their evolutionary divergence after the duplication, remains unclear. In this study, we investigated the evolutionary history of the duplicate genes for gaining insights into the process of RGL.Results: We reconstructed phylogenetic relationships of DPL copies from all 15 diploid species representing six genome types of rice genus and then found that all the DPL copies from the latest diverged A- and B-genome gather into one monophyletic clade. Southern blot analysis also detected definitely two DPL copies only in A- and B-genome. High conserved collinearity can be observed between A- and B-genomic segments containing DPL1 and DPL2 respectively but not between DPL1 and DPL2 segments. Investigations of transposon elements indicated that DPL duplication is related to DNA transposons. Likelihood-based analyses with branch models showed a relaxation of selective constraint in DPL1 lineage but an enhancement in DPL2 lineage after DPL duplication. Sequence analysis also indicated that quite a few defective DPL1 can be found in 6 wild and cultivated species out of all 8 species of A-genome but only one defective DPL2 occurs in a cultivated rice subspecies. Conclusions: DPL duplication of rice originated in the recent common ancestor of A- and B-genome about 6.76 million years ago and the duplication was possibly caused by DNA transposons. The DPL1 is a redundant copy and has being in the process of pseudogenization, suggesting that artificial selection may play an important role in forming the RGL of DPLs between two rice subspecies during the domestication.

Karyotype evolution in the Pinaceae: implication with molecular phylogeny

Genome ◽  
2012 ◽  
Vol 55 (11) ◽  
pp. 735-753 ◽  
Author(s):  
K.K. Nkongolo ◽  
M. Mehes-Smith
Keyword(s):  
Evolutionary History ◽  
Structural Changes ◽  
Karyotype Evolution ◽  
Diploid Species ◽  
Telomeric Sequence ◽  
The Family ◽  
Molecular Phylogenetic ◽  
History Of ◽  
Numeric Data

The family Pinaceae is made up mostly of diploid species (2n = 24). Systematization of karyotype analysis was developed to make comparison of intra- and interspecific karyotypes among the Pinaceae more accurate and reliable. Considering all parameters, the genera Pseudotsuga and Pseudolarix have the “most derived” (or advanced) and asymmetric karyotypes in the Pinaceae, followed by Larix, Picea, Abies, and Cedrus. The genus Pinus was the “least derived” (or ancestral) of all the genera of the Pinaceae analyzed. Differences in karyotype formulae and asymmetry indices were found among species within the same genera, suggesting that structural changes may have contributed to the diversification of the genus. This review is a detailed analysis of comparative karyotyping based on similar parameters, including numeric data and cytogenetic information. Telomeric sequence repeats and rDNA distribution in the Pinaceae were surveyed. The role of transposition in rDNA chromosome distribution is analyzed. Cytogenetic implications of hybridization between related species are reported. Likewise, the relationships between molecular phylogenetic and karyotype evolution is discussed in light of several reports. Within many genera, chromosomal organization was conserved despite independent molecular divergence and adaptation through the evolutionary history of the species of the Pinaceae.

scholarly journals Episodes of Rapid Recovery of the Functional Activity of the ras85D Gene in the Evolutionary History of Phylogenetically Distant Drosophila Species

2022 ◽  
Vol 12 ◽  
Author(s):  
A. I. Chekunova ◽  
S. Yu. Sorokina ◽  
E. A. Sivoplyas ◽  
G. N. Bakhtoyarov ◽  
P. A. Proshakov ◽  
...  
Keyword(s):  
Functional Activity ◽  
Promoter Region ◽  
Evolutionary History ◽  
Structural Changes ◽  
Regulatory Region ◽  
Evolutionary Origin ◽  
Regulatory Sequences ◽  
Structural Rearrangements ◽  
Evolutionary Variation ◽  
History Of

As assemblies of genomes of new species with varying degrees of relationship appear, it becomes obvious that structural rearrangements of the genome, such as inversions, translocations, and transposon movements, are an essential and often the main source of evolutionary variation. In this regard, the following questions arise. How conserved are the regulatory regions of genes? Do they have a common evolutionary origin? And how and at what rate is the functional activity of genes restored during structural changes in the promoter region? In this article, we analyze the evolutionary history of the formation of the regulatory region of the ras85D gene in different lineages of the genus Drosophila, as well as the participation of mobile elements in structural rearrangements and in the replacement of specific areas of the promoter region with those of independent evolutionary origin. In the process, we substantiate hypotheses about the selection of promoter elements from a number of frequently repeated motifs with different degrees of degeneracy in the ancestral sequence, as well as about the restoration of the minimum required set of regulatory sequences using a conversion mechanism or similar.

scholarly journals The Aquilegia genome reveals a hybrid origin of core eudicots

2018 ◽  
Author(s):  
Gökçe Aköz ◽  
Magnus Nordborg
Keyword(s):  
Evolutionary History ◽  
Genetic Material ◽  
Diploid Species ◽  
Hybrid Origin ◽  
The Core ◽  
Whole Genome Duplications ◽  
Core Eudicots ◽  
Eventual Return ◽  
Genome Duplications ◽  
History Of

AbstractBackgroundWhole-genome duplications (WGD) have dominated the evolutionary history of plants. One consequence of WGD is a dramatic restructuring of the genome as it undergoes diploidization, a process under which deletions and rearrangements of various sizes scramble the genetic material, leading to a repacking of the genome and eventual return to diploidy. Here, we investigate the history of WGD in the columbine genus Aquilegia, a basal eudicot, and use it to illuminate the origins of the core eudicots.ResultsWithin-genome synteny confirms that columbines are ancient tetraploids, and comparison with the grape genome reveals that this tetraploidy appears to be shared with the core eudicots. Thus, the ancient gamma hexaploidy found in all core eudicots must have involved a two-step process: first tetraploidy in the ancestry of all eudicots, then hexaploidy in the ancestry of core eudicots. Furthermore, the precise pattern of synteny sharing suggests that the latter involved allopolyploidization, and that core eudicots thus have a hybrid origin.ConclusionsNovel analyses of synteny sharing together with the well-preserved structure of the columbine genome reveal that the gamma hexaploidy at the root of core eudicots is likely a result of hybridization between a tetraploid and a diploid species.

scholarly journals Evolution and diversity of the wild rice Oryza officinalis complex, across continents genome types, and ploidy levels

2020 ◽  
Author(s):  
Matt Shenton ◽  
Masaaki Kobayashi ◽  
Shin Terashima ◽  
Hajime Ohyanagi ◽  
Dario Copetti ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Gene Pool ◽  
Evolutionary History ◽  
Diploid Species ◽  
Oryza Officinalis ◽  
Genome Species ◽  
C Genome ◽  
History Of ◽  
Tertiary Gene Pool ◽  
Oryza Officinalis Complex

Abstract The Oryza officinalis complex is the largest species group in Oryza, with more than nine species from four continents, and is a tertiary gene pool that can be exploited in breeding programs for the improvement of cultivated rice. Most diploid and tetraploid members of this group have a C genome. Using a new reference C genome for the diploid species Oryza officinalis, and draft genomes for two other C genome diploid species O. eichingeri and O. rhizomatis, we examine the influence of transposable elements on genome structure and provide a detailed phylogeny and evolutionary history of the Oryza C genomes. The O. officinalis genome is 1.6 times larger than the A genome of cultivated O. sativa, mostly due to proliferation of Gypsy type long-terminal repeat (LTR) transposable elements, but overall syntenic relationships are maintained with other Oryza genomes (A, B and F). Draft genome assemblies of the two other C genome diploid species, O. eichingeri and O. rhizomatis, and short-read resequencing of a series of other C genome species and accessions reveal that after the divergence of the C genome progenitor, there was still a substantial degree of variation within the C genome species through proliferation and loss of both DNA and LTR transposable elements. We provide a detailed phylogeny and evolutionary history of the Oryza C genomes, and a genomic resource for the exploitation of the Oryza tertiary gene pool.

scholarly journals Resurrecting embryos of the tuatara, Sphenodon punctatus , to resolve vertebrate phallus evolution

2015 ◽  
Vol 11 (10) ◽  
pp. 20150694 ◽  
Author(s):  
Thomas J. Sanger ◽  
Marissa L. Gredler ◽  
Martin J. Cohn
Keyword(s):  
Evolutionary History ◽  
Three Dimensional ◽  
External Genitalia ◽  
Evolutionary Origin ◽  
Victorian Era ◽  
Evolutionary Origins ◽  
Genital Development ◽  
Dimensional Reconstruction ◽  
Sphenodon Punctatus ◽  
History Of

The breadth of anatomical and functional diversity among amniote external genitalia has led to uncertainty about the evolutionary origins of the phallus. In several lineages, including the tuatara, Sphenodon punctatus , adults lack an intromittent phallus, raising the possibility that the amniote ancestor lacked external genitalia and reproduced using cloacal apposition. Accordingly, a phallus may have evolved multiple times in amniotes. However, similarities in development across amniote external genitalia suggest that the phallus may have a single evolutionary origin. To resolve the evolutionary history of amniote genitalia, we performed three-dimensional reconstruction of Victorian era tuatara embryos to look for embryological evidence of external genital initiation. Despite the absence of an intromittent phallus in adult tuataras, our observations show that tuatara embryos develop genital anlagen. This illustrates that there is a conserved developmental stage of external genital development among all amniotes and suggests a single evolutionary origin of amniote external genitalia.

scholarly journals The Aquilegia genome reveals a hybrid origin of core eudicots

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Gökçe Aköz ◽  
Magnus Nordborg
Keyword(s):  
Evolutionary History ◽  
Genetic Material ◽  
Diploid Species ◽  
Hybrid Origin ◽  
The Core ◽  
Whole Genome Duplications ◽  
Core Eudicots ◽  
Eventual Return ◽  
Genome Duplications ◽  
History Of

Abstract Background Whole-genome duplications (WGDs) have dominated the evolutionary history of plants. One consequence of WGD is a dramatic restructuring of the genome as it undergoes diploidization, a process under which deletions and rearrangements of various sizes scramble the genetic material, leading to a repacking of the genome and eventual return to diploidy. Here, we investigate the history of WGD in the columbine genus Aquilegia, a basal eudicot, and use it to illuminate the origins of the core eudicots. Results Within-genome synteny confirms that columbines are ancient tetraploids, and comparison with the grape genome reveals that this tetraploidy appears to be shared with the core eudicots. Thus, the ancient gamma hexaploidy found in all core eudicots must have involved a two-step process: first, tetraploidy in the ancestry of all eudicots, then hexaploidy in the ancestry of core eudicots. Furthermore, the precise pattern of synteny sharing suggests that the latter involved allopolyploidization and that core eudicots thus have a hybrid origin. Conclusions Novel analyses of synteny sharing together with the well-preserved structure of the columbine genome reveal that the gamma hexaploidy at the root of core eudicots is likely a result of hybridization between a tetraploid and a diploid species.

scholarly journals Review of the Genus Andropogon (Poaceae: Andropogoneae) in America Based on Cytogenetic Studies

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Nicolás Nagahama ◽  
Guillermo A. Norrmann
Keyword(s):  
North America ◽  
Cytogenetic Analysis ◽  
Evolutionary History ◽  
New World ◽  
Diploid Species ◽  
Strong Support ◽  
Related Genus ◽  
Cytogenetic Studies ◽  
History Of ◽  
New Hypothesis

Andropogon is a pantropical grass genus comprising 100–120 species and found mainly in the grasslands of Africa and the Americas. In the new world the genus is represented by approximately sixty (diploids or hexaploids) species grouped in three sections. The hexaploid condition occurs only in the Americas and the full process of this origin is still uncertain, although cytogenetic analysis coupled with taxonomic evidence have provided strong support for new hypothesis. Stebbins proposed the first hypothesis suggesting that the origin of polyploidy in species of Andropogon in North America resulted from duplication of the genome of some diploid species, and then by intergeneric crosses with species of a related genus. Since then, numerous studies were performed to clarify the evolutionary history of the genus in America. In this paper, we present a review of cytogenetic studies in the American Andropogon species during the last four decades.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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