scholarly journals Polyploidy and Speciation in Pteris (Pteridaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Yi-Shan Chao ◽  
Ho-Yih Liu ◽  
Yu-Chung Chiang ◽  
Wen-Liang Chiou
Keyword(s):  
Reproductive Biology ◽  
Evolutionary History ◽  
Base Number ◽  
Ploidy Levels ◽  
Cytological Data ◽  
The Relationship ◽  
Complex Evolutionary History

The highest frequency of polyploidy among plants is considered to occur in the Pteridophytes. In this study, we focused on polyploidy displayed by a specific fern taxon, the genus Pteris L. (Pteridaceae), comprising over 250 species. Cytological data from 106 Pteris species were reviewed. The base number of chromosomes in Pteris is 29. Polyploids are frequently found in Pteris, including triploids, tetraploids, pentaploids, hexaploids, and octoploids. In addition, an aneuploid species, P. deltodon Bak., has been recorded. Furthermore, the relationship between polyploidy and reproductive biology is reviewed. Among these 106 Pteris species, 60% exhibit polyploidy: 22% show intraspecific polyploidy and 38% result from polyploid speciation. Apogamous species are common in Pteris. Diploids are the most frequent among Pteris species, and they can be sexual or apogamous. Triploids are apogamous; tetraploids are sexual or apogamous. Most Pteris species have one to two ploidy levels. The diverse ploidy levels suggest that these species have a complex evolutionary history and their taxonomic problems require further clarification.

scholarly journals Genetic Diversity of Rice stripe necrosis virus and New Insights into Evolution of the Genus Benyvirus

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 737
Author(s):  
Issiaka Bagayoko ◽  
Marcos Giovanni Celli ◽  
Gustavo Romay ◽  
Nils Poulicard ◽  
Agnès Pinel-Galzi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Sierra Leone ◽  
Evolutionary History ◽  
Molecular Diversity ◽  
Genomic Data ◽  
Gene Recombination ◽  
Necrosis Virus ◽  
History Of ◽  
Complex Evolutionary History

The rice stripe necrosis virus (RSNV) has been reported to infect rice in several countries in Africa and South America, but limited genomic data are currently publicly available. Here, eleven RSNV genomes were entirely sequenced, including the first corpus of RSNV genomes of African isolates. The genetic variability was differently distributed along the two genomic segments. The segment RNA1, within which clusters of polymorphisms were identified, showed a higher nucleotidic variability than did the beet necrotic yellow vein virus (BNYVV) RNA1 segment. The diversity patterns of both viruses were similar in the RNA2 segment, except for an in-frame insertion of 243 nucleotides located in the RSNV tgbp1 gene. Recombination events were detected into RNA1 and RNA2 segments, in particular in the two most divergent RSNV isolates from Colombia and Sierra Leone. In contrast to BNYVV, the RSNV molecular diversity had a geographical structure with two main RSNV lineages distributed in America and in Africa. Our data on the genetic diversity of RSNV revealed unexpected differences with BNYVV suggesting a complex evolutionary history of the genus Benyvirus.

Rhizobial plasmids — replication, structure and biological role

2012 ◽  
Vol 7 (4) ◽  
pp. 571-586 ◽  
Author(s):  
Andrzej Mazur ◽  
Piotr Koper
Keyword(s):  
Genome Organization ◽  
Soil Bacteria ◽  
Evolutionary History ◽  
Bacterial Genome ◽  
Biological Role ◽  
Genome Architecture ◽  
Genomic Knowledge ◽  
History Of ◽  
Cryptic Plasmids ◽  
Complex Evolutionary History

AbstractSoil bacteria, collectively named rhizobia, can establish mutualistic relationships with legume plants. Rhizobia often have multipartite genome architecture with a chromosome and several extrachromosomal replicons making these bacteria a perfect candidate for plasmid biology studies. Rhizobial plasmids are maintained in the cells using a tightly controlled and uniquely organized replication system. Completion of several rhizobial genome-sequencing projects has changed the view that their genomes are simply composed of the chromosome and cryptic plasmids. The genetic content of plasmids and the presence of some important (or even essential) genes contribute to the capability of environmental adaptation and competitiveness with other bacteria. On the other hand, their mosaic structure results in the plasticity of the genome and demonstrates a complex evolutionary history of plasmids. In this review, a genomic perspective was employed for discussion of several aspects regarding rhizobial plasmids comprising structure, replication, genetic content, and biological role. A special emphasis was placed on current post-genomic knowledge concerning plasmids, which has enriched the view of the entire bacterial genome organization by the discovery of plasmids with a potential chromosome-like role.

scholarly journals Population Genomic Analysis of ALMS1 in Humans Reveals a Surprisingly Complex Evolutionary History

2009 ◽  
Vol 26 (6) ◽  
pp. 1357-1367 ◽  
Author(s):  
Laura B. Scheinfeldt ◽  
Shameek Biswas ◽  
Jennifer Madeoy ◽  
Caitlin F. Connelly ◽  
Eric E. Schadt ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Genomic Analysis ◽  
Population Genomic ◽  
Complex Evolutionary History

scholarly journals Gonadal morphology, histology and spermatogenesis of striped piggy fish, Pomadasys stridens (Forsskal, 1775) (Family: Pomadasyidae) from Karachi coast, Pakistan.

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Amtyaz Safi
Keyword(s):  
Reproductive Biology ◽  
Sexual Maturity ◽  
Fat Body ◽  
Histological Structure ◽  
Reproductive State ◽  
Female Fish ◽  
Structure Morphology ◽  
Morphological Differences ◽  
The Right ◽  
The Relationship

A study was conducted on the histological structure, morphology of gonads and spermatogenesis of testes of the striped piggy fish, Pomadasys stridens from Karachi coast of Pakistan. The reproductive biology of grunt fishes, and the Pomadasys stridens in particular, is not well understood with respect to functional morphology and histology of the gonads in relation to sexual maturity. In the course of an investigation of the genetic variability of Pomadasys stridens, differences in morphology were observed between the right and left gonad of male and female fish and the size of the fat body associated with the gonads. Histological examinations were made to determine the relationship between these morphological differences and the reproductive state of the gonads. Findings made from this paper are gonad morphology, histology, and spermatogenesis and relate them to the reproductive biology of this species.

scholarly journals Does increased information about reproductive potential result in better prediction of recruitment?

2011 ◽  
Vol 68 (8) ◽  
pp. 1361-1368 ◽  
Author(s):  
M. Joanne Morgan ◽  
Alfonso Perez-Rodriguez ◽  
Fran Saborido-Rey
Keyword(s):  
Reproductive Biology ◽  
Egg Production ◽  
Gadus Morhua ◽  
Reproductive Potential ◽  
Essential Element ◽  
Greenland Halibut ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
Difficult Challenge ◽  
The Relationship ◽  
Hippoglossoides Platessoides

The relationship between stock size and recruitment is an essential element in the understanding of the productivity of a population. However, predicting the number of recruits produced by a population has proven to be a difficult challenge. This may in part be a result of poor estimation of reproductive potential (RP). We determined if including increased information on reproductive biology in indices of RP results in better predictions of recruitment. We investigated some of the conditions that lead to better (or worse) recruitment prediction when more biologically complex indices of RP are used. Data from four populations in the Northwest Atlantic were examined: southern Grand Bank (NAFO Division 3NO) cod ( Gadus morhua ), Flemish Cap (NAFO Division 3M) cod, Newfoundland (NAFO Division 3LNO) American plaice ( Hippoglossoides platessoides ), and Greenland halibut ( Reinhardtius hippoglossoides ) (NAFO Subarea 2 + Division 3KLMNO). Stock–recruit models paired with complex indices of RP gave a better estimate of recruitment in slightly more than half of the tests conducted. When there were larger trends in the reproductive biology (maturity at age, sex ratio and egg production), more complex indices of RP were more likely to provide a better estimate of recruitment.

A total evidence approach using palynological characters to infer the complex evolutionary history of the Asian Impatiens (Balsaminaceae)

Taxon ◽  
2012 ◽  
Vol 61 (2) ◽  
pp. 355-367 ◽  
Author(s):  
Steven B. Janssens ◽  
Yi Song Wilson ◽  
Yong-Ming Yuan ◽  
Anne Nagels ◽  
Erik F. Smets ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Total Evidence ◽  
History Of ◽  
Complex Evolutionary History

Species-specific patterns of the use of burrows of Upogebia Leach, 1814 (Decapoda: Gebiidea: Upogebiidae) by the symbiotic alpheid shrimps Stenalpheops anacanthus Miya, 1997 and Athanas japonicus Kubo, 1936 (Decapoda: Caridea: Alpheidae) as revealed by laboratory quantification

2020 ◽  
Author(s):  
Yumi Henmi ◽  
Gyo Itani
Keyword(s):  
Evolutionary Biology ◽  
Evolutionary History ◽  
The Body ◽  
Symbiotic Relationship ◽  
Use Patterns ◽  
Species Specific ◽  
Burrow Use ◽  
First Time ◽  
The Relationship ◽  
Observation Period

Abstract Many alpheid shrimps live symbiotically on the body surface or inside the bodies of other invertebrates, while others use burrows made by other animals. The burrow symbiosis of alpheid shrimps is poorly studied in the context of ecology, probably because the cryptic infaunal nature of the relationship is hard to observe. The limited knowledge of the pattern of burrow use by alpheid shrimps leaves a gap in our understanding of their evolutionary history. We described and compared the behavior of Stenalpheops anacanthus  Miya, 1997 and Athanas japonicus  Kubo, 1936, two alpheid species living symbiotically in the burrows of the same host, Upogebia yokoyai  Makarov, 1938. We found that both alpheid species used U. yokoyai burrows in aquaria, but their burrow use patterns were quite different. The average time taken for S. anacanthus to enter the burrow for the first time was much shorter (1 min) than that of A. japonicus (13 min). Subsequently, S. anacanthus made longer use of the burrow (80% of the observation period) than A. japonicus (49%). The tail-first exit frequency, which may indicate a sudden expulsion from the burrow by the host, was more frequent in A. japonicus (25%) than in S. anacanthus (7%). Such differences could be attributed to the nature of the symbiotic relationship, obligate in S. anacanthus but facultative in A. japonicus. Because of the diversity of symbiotic lifestyles, there is considerable potential to study the ecology and evolutionary biology of burrow-symbiotic alpheids further.

scholarly journals ANALYSIS OFALEXANDRIUM TAMARENSE(DINOPHYCEAE) GENES REVEALS THE COMPLEX EVOLUTIONARY HISTORY OF A MICROBIAL EUKARYOTE1

2012 ◽  
Vol 48 (5) ◽  
pp. 1130-1142 ◽  
Author(s):  
Cheong Xin Chan ◽  
Marcelo B. Soares ◽  
Maria F. Bonaldo ◽  
Jennifer H. Wisecaver ◽  
Jeremiah D. Hackett ◽  
...  
Keyword(s):  
Evolutionary History ◽  
History Of ◽  
Complex Evolutionary History
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