scholarly journals The "Crustacean Seas" — an evolutionary perspective on the Ponto–Caspian peracarids

2005 ◽  
Vol 62 (3) ◽  
pp. 505-517 ◽  
Author(s):  
Melania EA Cristescu ◽  
Paul DN Hebert
Keyword(s):  
Ribosomal Rna ◽  
Adaptive Radiation ◽  
Nuclear Gene ◽  
Taxonomic Status ◽  
Mitochondrial Genes ◽  
Evolutionary Perspective ◽  
Intraspecific Divergence ◽  
Geographic Structure ◽  
Colonization Event ◽  
History Of

A spectacular adaptive radiation of crustaceans has occurred in the Black, Caspian, and Aral seas. This study tests several evolutionary scenarios based on the extent of genetic differentiation and the phylogenetic relationships among endemic mysids and gammarid amphipods from the Black and Caspian seas. Molecular phylogenies for these taxa were based on two mitochondrial genes: cytochrome c oxidase subunit I and the large ribosomal RNA subunit (16S), and one nuclear gene, the large ribosomal RNA subunit (28S). The results support the monophyly of the Ponto–Caspian gammarids (genera Dikerogammarus, Echinogammarus, Obesogammarus, and Pontogammarus), suggesting their origin from one colonization event. By contrast, several colonization events preceded the radiation of the Ponto–Caspian mysids (genera Limnomysis and Paramysis). Levels of intraspecific divergence were variable, with mysids showing either no geographic structure or deep genetic splits reflecting a long history of reproductive isolation between populations in marine settings and those in fresh waters. These findings suggest that the diversity of the Ponto–Caspian crustaceans has been underestimated and that species regarded as euryhaline are often composed of distinct evolutionary groups whose taxonomic status should be reevaluated.

scholarly journals Phylogeography of southern brown and golden bandicoots: implications for the taxonomy and distribution of endangered subspecies and species

2018 ◽  
Vol 66 (6) ◽  
pp. 379 ◽  
Author(s):  
Steven J. B. Cooper ◽  
Kym Ottewell ◽  
Anna J. MacDonald ◽  
Mark Adams ◽  
Margaret Byrne ◽  
...  
Keyword(s):  
Nuclear Gene ◽  
Taxonomic Status ◽  
Population Connectivity ◽  
Species Boundaries ◽  
Population Genetic Analysis ◽  
European Settlement ◽  
History Of ◽  
Current Species ◽  
East West

Southern brown (Isoodon obesulus) and golden (Isoodon auratus) bandicoots are iconic Australian marsupials that have experienced dramatic declines since European settlement. Conservation management programs seek to protect the remaining populations; however, these programs are impeded by major taxonomic uncertainties. We investigated the history of population connectivity to inform subspecies and species boundaries through a broad-scale phylogeographic and population genetic analysis of Isoodon taxa. Our analyses reveal a major east–west phylogeographic split within I. obesulus/I. auratus, supported by both mtDNA and nuclear gene analyses, which is not coincident with the current species or subspecies taxonomy. In the eastern lineage, all Tasmanian samples formed a distinct monophyletic haplotype group to the exclusion of all mainland samples, indicative of long-term isolation of this population from mainland Australia and providing support for retention of the subspecific status of the Tasmanian population (I. o. affinis). Analyses further suggest that I. o. obesulus is limited to south-eastern mainland Australia, representing a significant reduction in known range. However, the analyses provide no clear consensus on the taxonomic status of bandicoot populations within the western lineage, with further analyses required, ideally incorporating data from historical museum specimens to fill distributional gaps.

Patterns of distribution of tree frogs in Turkey based on molecular data

2012 ◽  
Vol 33 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Serkan Gül ◽  
Bilal Kutrup ◽  
Nurhayat Özdemir
Keyword(s):  
Ribosomal Rna ◽  
Nuclear Gene ◽  
Molecular Data ◽  
Mitochondrial Genes ◽  
Junior Synonym ◽  
Patterns Of Distribution ◽  
Hyla Arborea ◽  
Tree Frogs ◽  
Hyla Savignyi

Despite previous work on the phylogeny of Palearctic Hyla, several problems still exist regarding systematics of Hyla in Turkey. The systematics of tree frogs (Hyla orientalis and Hyla savignyi) in Turkey was studied using combined mitochondrial genes (12S ribosomal RNA and cytochrome b) and a nuclear gene (H3), and sampling a total of 102 individuals from 51 localities. We find that Hyla orientalis is represented by a single lineage, whereas Hyla savignyi was divided into two lineages by the mitochondrial genes, but not the nuclear gene. We also confirm that Hyla arborea schelkownikowi is a junior synonym of Hyla orientalis.

Taxonomic status of the amphi-Atlantic species Plesionika acanthonotus (Caridea: Pandalidae): a multi-locus and morphological approach

Zootaxa ◽  
2019 ◽  
Vol 4590 (4) ◽  
pp. 457
Author(s):  
IRENE A. CARDOSO ◽  
GHENNIE T. RODRÍGUEZ-REY ◽  
MARIANA TEROSSI ◽  
CÁTIA BARTILOTTI ◽  
CRISTIANA S. SEREJO
Keyword(s):  
Dna Sequences ◽  
Nuclear Gene ◽  
Taxonomic Status ◽  
Distinct Species ◽  
Mitochondrial Genes ◽  
Valid Species ◽  
Western Atlantic ◽  
Morphological Studies ◽  
Histone 3 ◽  
Two Populations

Deep-sea shrimps of the species Plesionika acanthonotus (Smith, 1882) and P. holthuisi Crosnier & Forest, 1968 are morphologically similar and exhibit overlapping amphi-Atlantic distributions. In the literature, through morphological studies, there are reports of doubts about the validity of P. holthuisi and some authors believe that the eastern and western Atlantic populations of P. acanthonothus could represent two distinct species. The objective of the present study was to use molecular data to elucidate the taxonomic status of the two populations of P. acanthonothus. DNA sequences of two mitochondrial genes (16S rDNA and Cytochrome Oxidase subunit I) and a nuclear gene (Histone 3) were obtained for both species and for both populations of P. acanthonotus. The sequences were also obtained from Genbank for comparison. The trees (separate and multi-locus/partitioned genes) were generated by Bayesian Inference analyzes, and genetic divergence (Kimura-2-parameters) was also calculated. All specimens that had their DNA sequenced were examined morphologically to confirm their identification; morphological variations were noted. The genetic data showed that Plesionika holthuisi is closely related to P. acanthonotus, but clearly separated, indicating that P. holthuisi is a valid species. In the multi-locus analysis, the P. acanthonothus specimens were divided into two clades, one with the eastern Atlantic specimens and another with the western Atlantic specimens. However, this genetic separation was considered to be a population structuring for three reasons: (1) the genetic divergences of the two mitochondrial genes between these two groups (eastern Atlantic X western Atlantic) were smaller than the interspecific divergence for Plesionika; (2) the P. acanthonothus sequences of the Histone 3 gene showed no genetic variation; (3) in the analyzed individuals, no valid morphological character was found to support this separation. Thus, the conclusion of this study is that P. holthuisi probably is a valid species and P. acanthonothus presents two populations with mitochondrial divergences that could be in the process of speciation, but which currently represent only one species.

scholarly journals Nuclear Gene Dosage Effects Upon the Expression of Maize Mitochondrial Genes

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1711-1721
Author(s):  
Donald L Auger ◽  
Kathleen J Newton ◽  
James A Birchler
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Gene Dosage ◽  
Nuclear Gene ◽  
Eukaryotic Cell ◽  
Mitochondrial Genes ◽  
Northern Analysis ◽  
Α Subunit ◽  
Dosage Effects ◽  
A Genome

Abstract Each mitochondrion possesses a genome that encodes some of its own components. The nucleus encodes most of the mitochondrial proteins, including the polymerases and factors that regulate the expression of mitochondrial genes. Little is known about the number or location of these nuclear factors. B-A translocations were used to create dosage series for 14 different chromosome arms in maize plants with normal cytoplasm. The presence of one or more regulatory factors on a chromosome arm was indicated when variation of its dosage resulted in the alteration in the amount of a mitochondrial transcript. We used quantitative Northern analysis to assay the transcript levels of three mitochondrially encoded components of the cytochrome c oxidase complex (cox1, cox2, and cox3). Data for a nuclearly encoded component (cox5b) and for two mitochondrial genes that are unrelated to cytochrome c oxidase, ATP synthase α-subunit and 18S rRNA, were also determined. Two tissues, embryo and endosperm, were compared and most effects were found to be tissue specific. Significantly, the array of dosage effects upon mitochondrial genes was similar to what had been previously found for nuclear genes. These results support the concept that although mitochondrial genes are prokaryotic in origin, their regulation has been extensively integrated into the eukaryotic cell.

Streptococcus pluranimalium meningoencephalitis in a horse

2021 ◽  
pp. 104063872110234
Author(s):  
Dah-Jiun Fu ◽  
Akhilesh Ramachandran ◽  
Craig Miller
Keyword(s):  
Ribosomal Rna ◽  
Cross Sections ◽  
Nucleotide Sequencing ◽  
Formalin Fixed Paraffin ◽  
Quarter Horse ◽  
Formalin Fixed Paraffin Embedded ◽  
History Of ◽  
The Brain ◽  
Gram Positive Cocci ◽  
Formalin Fixed

A 3-y-old, female Quarter Horse with a history of acute neurologic signs was found dead and was submitted for postmortem examination. Areas of petechial and ecchymotic hemorrhage were present on cross-sections of the cerebrum, cerebellum, and brainstem. Histologic examination of the brain revealed severe, purulent meningoencephalitis and vasculitis with a myriad of intralesional gram-positive cocci. Streptococcus pluranimalium was identified from formalin-fixed, paraffin-embedded tissue obtained from sites with active lesions by PCR and nucleotide sequencing of bacterial 16S ribosomal RNA. S. pluranimalium should be considered as a cause of meningoencephalitis in a horse.

A description of the second species of the genus Bleptus Eaton, 1885 (Ephemeroptera: Heptageniidae) from Japan, and phylogenetic relationships of two Bleptus mayflies inferred from mitochondrial and nuclear gene sequences

Zootaxa ◽  
2021 ◽  
Vol 4974 (2) ◽  
pp. 333-360
Author(s):  
KOJI TOJO ◽  
KEN MIYAIRI ◽  
YUTO KATO ◽  
AYANA SAKANO ◽  
TOMOYA SUZUKI
Keyword(s):  
Phylogenetic Analyses ◽  
Ribosomal Subunit ◽  
Nuclear Gene ◽  
Taxonomic Status ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Gene Sequences ◽  
Molecular Phylogenetic ◽  
Black Band ◽  
Relationship Of

A new mayfly species, Bleptus michinokuensis sp. nov. (Ephemeroptera: Heptageniidae) is described on the basis of specimens of male and female adults and mature nymphs collected at a seepage zone of a small freshwater branch of the ‘Tachiya-zawa-gawa’ River located amongst the northern foothills of Mt. Gassan (Shonai-machi Town, Yamagata Prefecture, Japan). This new Bleptus species is characterized by its clear fore and hind wings. That is, they neither exhibit the distinct black band on the fore wings, nor the characteristic darkened margins along the edges of both the fore and hind wings. Rather it has a blackish colored terminal half of its fore legs (i.e., tibial, tarsal and pretarsal segments). These features differ clearly when comparing them to the other known species, Bleptus fasciatus Eaton. The information and data describing the habitat and distribution range of this new species are also noted. We also examined and discussed the genetic relationship of two Bleptus mayflies to settle the taxonomic status, inferred from the partially sequenced cytochrome c oxidase subunit I (COI) and large mitochondrial ribosomal subunit (16S rRNA) genes, and also the nuclear internal transcribed spacer 2 (ITS2) gene sequences. Consequently, phenetic and molecular phylogenetic analyses agreed well in terms of clustering. 

Molecular phylogeny of diploid Hordeum species and incongruence between chloroplast and nuclear datasets

Genome ◽  
2011 ◽  
Vol 54 (12) ◽  
pp. 986-992 ◽  
Author(s):  
Huan Wang ◽  
Dongfa Sun ◽  
Genlou Sun
Keyword(s):  
Evolutionary History ◽  
Nuclear Gene ◽  
Intergenic Spacer ◽  
Molecular Data ◽  
Genome Species ◽  
Different Types ◽  
History Of ◽  
Morphological And Molecular Data ◽  
Hordeum Species ◽  
Eurasian Species

The phylogeny of diploid Hordeum species has been studied using both chloroplast and nuclear gene sequences. However, the studies of different nuclear datasets of Hordeum species often arrived at similar conclusions, whereas the studies of different chloroplast DNA data generally resulted in inconsistent conclusions. Although the monophyly of the genus is well supported by both morphological and molecular data, the intrageneric phylogeny is still a matter of controversy. To better understand the evolutionary history of Hordeum species, two chloroplast gene loci (trnD-trnT intergenic spacer and rps16 gene) and one nuclear marker (thioreoxin-like gene (HTL)) were used to explore the phylogeny of Hordeum species. Two obviously different types of trnD-trnT sequences were observed, with an approximately 210 base pair difference between these two types: one for American species, another for Eurasian species. The trnD-trnT data generally separated the diploid Hordeum species into Eurasian and American clades, with the exception of Hordeum marinum subsp. gussoneanum. The rps16 data also grouped most American species together and suggested that Hordeum flexuosum has a different plastid type from the remaining American species. The nuclear gene HTL data clearly divided Hordeum species into two clades: the Xu + H genome clade and the Xa + I genome clade. Within clades, H genome species were well separated from the Xu species, and the I genome species were well separated from the Xa genome species. The incongruence between chloroplast and nuclear datasets was found and discussed.

The complete mitochondrial genome of the jumping grasshopper Sinopodisma pieli (Orthoptera: Acrididae) and the phylogenetic analysis of Melanoplinae

Zootaxa ◽  
2017 ◽  
Vol 4363 (4) ◽  
pp. 506
Author(s):  
HUAXUAN LIU ◽  
LIYUN YAN ◽  
GUOFANG JIANG
Keyword(s):  
Phylogenetic Analysis ◽  
Mitochondrial Genome ◽  
Ribosomal Rna ◽  
Complete Mitochondrial Genome ◽  
Taxonomic Status ◽  
Polymerase Chain Reaction Method ◽  
Ribosomal Rna Genes ◽  
Start Codon ◽  
Trna Genes ◽  
Rna Genes

In this study, we reported the complete mitochondrial genome (mitogenome) of Sinopodisma pieli by polymerase chain reaction method for the first time, the type species of the genus Sinopodisma. Its mitogenome was a circular DNA molecule of 15,625 bp in length, with 76.0% A+T, and contained 13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes and one A+T control region. The overall base composition of the S. pieli mitogenome was 42.8% for A, 33.2% for T, 13.5% for C, and 10.5% for G, respectively. All 13 mitochondrial PCGs shared the start codon ATN. Twelve of the PCGs ended with termination codon TAA and TAG, while cytochrome coxidase subunit 1 (COI) utilized an incomplete T as terminator codon. All tRNA genes could be folded into the typical cloverleaf secondary structure, except trnS(AGN) lacking of dihydrouridine arm. The sizes of the large and small ribosomal RNA genes were 1379 bp and 794 bp, respectively. The A+T rich region was 798 bp in length and contained 88.5% AT content. A phylogenetic analysis based on 13 PCGs by using Bayesian inference (BI) and maximum likelihood (ML) revealed that Sinopodisma is not monophyletic group. We think that the name and taxonomic status of S. tsinlingensis are right, and it should not be moved into the genus Pedopodisma. These data will provide important information for a better understanding of the population genetics and species identification for Sinopodisma. 

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