Genetic Divergence Between South African Helcion Species and North-East Atlantic H. Pellucidum (Mollusca: Patellogastropoda)

1997 ◽  
Vol 77 (4) ◽  
pp. 1139-1150 ◽  
Author(s):  
L.I. Weber ◽  
D.R. Gray ◽  
A.N. Hodgson ◽  
S.J. Hawkins
Keyword(s):  
South African ◽  
Genetic Divergence ◽  
Genetic Relationships ◽  
Taxonomic Status ◽  
Genetic Distances ◽  
Group Method ◽  
Congeneric Species ◽  
East Atlantic ◽  
North East ◽  
The North

Allozyme electrophoresis was used to estimate the genetic divergence between three species of South African Helcion and the north-east Atlantic H. pellucidum (Patellidae). At a finer level the genetic relationships among South African Helcion were explored. Twenty-one loci were resolved for all the species. High values of expected heterozygosities (0·202–0·341) were found for the genus. Phenetic analysis (UPGMA (unweighted pair-group method with artihmetic averaging) and Distance Wagner Procedure) and cladistic parsimony methods (alleles as binary characters and loci as multistate unordered characters) agreed in showing the same topology for the tree which represents the genetic relationships among Helcion species. The north-east Atlantic H. pellucidum was the most divergent species showing high values of Nei's genetic distances (1·423–1·654) with its South African congeners. In the literature such values of genetic divergence have been associated with non-congeneric species. The degree of genetic divergence (0·351–0·615) found within the South African branch was characteristic for congeneric species. The results of this study supported the monophyletic condition of this branch, and showed H. pectunculus and H. pruinosus to be more closely related to each other than to H. dunkeri. Nevertheless, the monophyly of the genus Helcion is uncertain and therefore its taxonomic status was questioned. A possible independent origin for northern and southern hemisphere species of Helcion is considered.

On the identity of Spio filicornis (O.F. Müller, 1776)—with the designation of a neotype, and the description of two new species from the North East Atlantic Ocean based on morphological and genetic studies

Zootaxa ◽  
2011 ◽  
Vol 2815 (1) ◽  
pp. 1 ◽  
Author(s):  
KARIN MEIßNER ◽  
ANDREAS BICK ◽  
RALF BASTROP
Keyword(s):  
Molecular Markers ◽  
New Species ◽  
Genetic Divergence ◽  
18S Rdna ◽  
Original Description ◽  
East Atlantic ◽  
Genetic Studies ◽  
North East ◽  
The North ◽  
Two New Species

The aim of this study is to solve taxonomic problems pertaining to Spio filicornis (O.F. Müller, 1776). The original description by O. F. Müller was very brief and type material was not deposited. Based on the literature the confusion about the identity of the species has been tremendous; e.g., it was only recently realized that at least two different species from the North and Baltic Seas could be identified as S. filicornis (Bick et al. 2010). The present study is based on material collected by the authors in 2009 at the type locality in Iluilârssuk, near Paamiut, SW Greenland. Spio filicornis is redescribed in detail and illustrated comprehensively. A neotype has been designated and deposited in the collection of Rostock University. Species formerly referred to as S. cf. filicornis from the North and Baltic Seas (Bick et al. 2010) are formally described as two new species, Spio arndti sp. nov., and S. symphyta sp. nov. The morphological diagnostic characters within Spio are discussed. Information on three molecular markers (16S rDNA, 18S rDNA, cytochrome c oxidase subunit I) is also provided. The genetic divergence between the three Spio species corroborates the taxonomic discrimination.

scholarly journals Population genetics meets phylogenetics: new insights into the relationships among members of the genus Euthynnus (family Scombridae)

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Judith Ollé ◽  
Laura Vilà-Valls ◽  
Jaime Alvarado-Bremer ◽  
Genoveva Cerdenares ◽  
Thuy Yen Duong ◽  
...  
Keyword(s):  
North Atlantic ◽  
Genetic Divergence ◽  
East Atlantic ◽  
North West ◽  
North East ◽  
The North ◽  
Worldwide Distribution ◽  
Allopatric Species ◽  
The North Atlantic ◽  
High Level

AbstractEuthynnus (family Scombridae) is a genus of marine pelagic fish species with a worldwide distribution that comprises three allopatric species: E. alletteratus, E. affinis and E. lineatus. All of them targeted by artisanal and commercial fisheries. We analyzed 263 individuals from Atlantic and Pacific Oceans using two genetic markers, the mtDNA Control Region (350 bp) and nuclear calmodulin (341 bp). The results obtained challenge the phylogeny of this group. We found a deep genetic divergence, probably at species level, within E. alletteratus, between the North Atlantic-Mediterranean and the Tropical East Atlantic. This deep genetic divergence was tested with several species delimitation methods. This complete phylogeographic association between the North Atlantic and the Tropical East Atlantic support the hypothesis of two cryptic species. In addition, population genetic heterogeneity was detected between the North East Atlantic–Mediterranean and North West Atlantic regions. Our results indicate two scales of differentiation in what is currently considered a single population. Accordingly, for management purposes, the populations of E. alletteratus, should be divided into a minimum of three management units. On the other hand, the high level of differentiation found in E. alletteratus contrasts with the shallow genetic divergence of E. affinis and E. lineatus.

On the identity of Spio filicornis (O.F. Müller, 1776)—with the designation of a neotype, and the description of two new species from the North East Atlantic Ocean based on morphological and genetic studies

Zootaxa ◽  
2011 ◽  
Vol 2815 (1) ◽  
Author(s):  
KARIN MEIßNER ◽  
ANDREAS BICK ◽  
RALF BASTROP
Keyword(s):  
Molecular Markers ◽  
New Species ◽  
Genetic Divergence ◽  
18S Rdna ◽  
Original Description ◽  
East Atlantic ◽  
Genetic Studies ◽  
North East ◽  
The North ◽  
Two New Species

The aim of this study is to solve taxonomic problems pertaining to Spio filicornis (O.F. Müller, 1776). The original description by O. F. Müller was very brief and type material was not deposited. Based on the literature the confusion about the identity of the species has been tremendous; e.g., it was only recently realized that at least two different species from the North and Baltic Seas could be identified as S. filicornis (Bick et al. 2010). The present study is based on material collected by the authors in 2009 at the type locality in Iluilârssuk, near Paamiut, SW Greenland. Spio filicornis is redescribed in detail and illustrated comprehensively. A neotype has been designated and deposited in the collection of Rostock University. Species formerly referred to as S. cf. filicornis from the North and Baltic Seas (Bick et al. 2010) are formally described as two new species, Spio arndti sp. nov., and S. symphyta sp. nov. The morphological diagnostic characters within Spio are discussed. Information on three molecular markers (16S rDNA, 18S rDNA, cytochrome c oxidase subunit I) is also provided. The genetic divergence between the three Spio species corroborates the taxonomic discrimination.

scholarly journals Thrust–wrench interference tectonics in the Gulf of Cadiz (Africa–Iberia plate boundary in the North-East Atlantic): Insights from analog models

2011 ◽  
Vol 289 (1-4) ◽  
pp. 135-149 ◽  
Author(s):  
João C. Duarte ◽  
Filipe M. Rosas ◽  
Pedro Terrinha ◽  
Marc-André Gutscher ◽  
Jacques Malavieille ◽  
...  
Keyword(s):  
Plate Boundary ◽  
Gulf Of Cadiz ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
Gulf Of Cádiz ◽  
Analog Models

Exceptional influx of oceanic species into the North Sea late 1997

1999 ◽  
Vol 79 (4) ◽  
pp. 737-739 ◽  
Author(s):  
M. Edwards ◽  
A.W.G. John ◽  
H.G. Hunt ◽  
J.A. Lindley
Keyword(s):  
North Sea ◽  
Indicator Species ◽  
Climatic Conditions ◽  
Historical Evidence ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
The North Sea ◽  
Oceanic Species

Continuous Plankton Recorder records from the North Sea and north-east Atlantic from September 1997 to March 1998 indicate an exceptional influx of oceanic indicator species into the North Sea. These inflow events, according to historical evidence, have only occurred sporadically during this century. This exceptional inflow and previous inflow events are discussed in relation to their similarity in terms of their physical and climatic conditions.

Artificial reefs in the North –East Atlantic area: Present situation, knowledge gaps and future perspectives

2021 ◽  
Vol 213 ◽  
pp. 105854
Author(s):  
Bianca Reis ◽  
Pieter van der Linden ◽  
Isabel Sousa Pinto ◽  
Emanuel Almada ◽  
Maria Teresa Borges ◽  
...  
Keyword(s):  
Present Situation ◽  
Artificial Reefs ◽  
Future Perspectives ◽  
East Atlantic ◽  
Knowledge Gaps ◽  
North East ◽  
The North ◽  
Atlantic Area

scholarly journals Genetic diversity in table grapes based on RAPD and microsatellite markers

2011 ◽  
Vol 46 (9) ◽  
pp. 1035-1044 ◽  
Author(s):  
Patrícia Coelho de Souza Leão ◽  
Sérgio Yoshimitsu Motoike
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
Genetic Relationships ◽  
Similarity Index ◽  
Genetic Distances ◽  
Table Grape ◽  
Group Method ◽  
Molecular Characteristics ◽  
Table Grapes ◽  
Pair Group

The objective of this work was to analyze the genetic diversity of 47 table grape accessions, from the grapevine germplasm bank of Embrapa Semiárido, using 20 RAPD and seven microsatellite markers. Genetic distances between pairs of accessions were obtained based on Jaccard's similarity index for RAPD data and on the arithmetic complement of the weighted index for microsatellite data. The groups were formed according to the Tocher's cluster analysis and to the unweighted pair‑group method with arithmetic mean (UPGMA). The microsatellite markers were more efficient than the RAPD ones in the identification of genetic relationships. Information on the genetic distance, based on molecular characteristics and coupled with the cultivar agronomic performance, allowed for the recommendation of parents for crossings, in order to obtain superior hybrids in segregating populations for the table grape breeding program of Embrapa Semiárido.

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