scholarly journals Taxonomic status of two morphotypes of Coryphaena hippurus (Perciformes: Coryphaenidae)

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Alan Bonner ◽  
Michelle R. Duarte ◽  
Rosa C. C. L. Souza ◽  
Cassiano Monteiro-Neto ◽  
Edson P. Silva
Keyword(s):  
Genetic Variation ◽  
Taxonomic Status ◽  
Brazilian Coast ◽  
Gene Pools ◽  
Fishing Pressure ◽  
Allozyme Electrophoresis ◽  
Coryphaena Hippurus ◽  
Biological Matter ◽  
Electrophoresis Method ◽  
Definition Of

ABSTRACT Two Coryphaena hippurus morphotypes (dourado and palombeta) are found along the Brazilian coast and are considered by Rio de Janeiro’s fisherman and fishmongers as two different species. Furthermore, these morphotypes are commercialized under different values and suffer different fishing pressure. Therefore, a definition of their taxonomic status is an important economic and biological matter. In order to investigate this problem, allozyme electrophoresis method was undertaken for seventeen loci on 117 individuals of C. hippurus sampled at Cabo Frio/RJ (Brazil). The data indicate homogeneity between the morphotypes gene pools. Nevertheless, differences were found for genetic variation among dourado and palombeta, especially due to alcohol dehydrogenase locus. Natural selection hypothesis is discussed in explaining these findings.

Genetic variation in the greater bilby (Macrotis lagotis)

1994 ◽  
Vol 1 (1) ◽  
pp. 46 ◽  
Author(s):  
Richard Southgate ◽  
Mark Adams
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Variability ◽  
Population Genetic ◽  
Taxonomic Status ◽  
Biological Species ◽  
Significant Loss ◽  
Allozyme Electrophoresis ◽  
Allozyme Data ◽  
Data Support

The taxonomic status of and genetic diversity amongst extant populations of the greater bilby, Macrotis lagotis, were assessed using allozyme electrophoresis. A total of 47 bilbies sampled from three geographic areas and two captive colonies were screened for 42 loci, six of which were polymorphic. The results are consistent with the view that all extant populations represent a single biological species. All populations were genetically very similar (Nei D's 0.000 to 0.004) and overall levels of within-population genetic variability were low (Ho 0.004 � 0.004 to 0.0026 � 0.017). The allozyme data support the hypothesis that there has been no significant loss of variability in the captive colonies when compared to the species as a whole.

scholarly journals Genetic Diversity of Landraces and Improved Varieties of Rice (Oryza sativa L.) in Taiwan

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ai-ling Hour ◽  
Wei-hsun Hsieh ◽  
Su-huang Chang ◽  
Yong-pei Wu ◽  
Han-shiuan Chin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Indigenous Peoples ◽  
Oryza Sativa L ◽  
Crop Improvement ◽  
Genetic Erosion ◽  
Germplasm Conservation ◽  
Gene Pools ◽  
Improved Varieties ◽  
Breeding Goals

Abstract Background Rice, the most important crop in Asia, has been cultivated in Taiwan for more than 5000 years. The landraces preserved by indigenous peoples and brought by immigrants from China hundreds of years ago exhibit large variation in morphology, implying that they comprise rich genetic resources. Breeding goals according to the preferences of farmers, consumers and government policies also alter gene pools and genetic diversity of improved varieties. To unveil how genetic diversity is affected by natural, farmers’, and breeders’ selections is crucial for germplasm conservation and crop improvement. Results A diversity panel of 148 rice accessions, including 47 cultivars and 59 landraces from Taiwan and 42 accessions from other countries, were genotyped by using 75 molecular markers that revealed an average of 12.7 alleles per locus with mean polymorphism information content of 0.72. These accessions could be grouped into five subpopulations corresponding to wild rice, japonica landraces, indica landraces, indica cultivars, and japonica cultivars. The genetic diversity within subpopulations was: wild rices > landraces > cultivars; and indica rice > japonica rice. Despite having less variation among cultivars, japonica landraces had greater genetic variation than indica landraces because the majority of Taiwanese japonica landraces preserved by indigenous peoples were classified as tropical japonica. Two major clusters of indica landraces were formed by phylogenetic analysis, in accordance with immigration from two origins. Genetic erosion had occurred in later japonica varieties due to a narrow selection of germplasm being incorporated into breeding programs for premium grain quality. Genetic differentiation between early and late cultivars was significant in japonica (FST = 0.3751) but not in indica (FST = 0.0045), indicating effects of different breeding goals on modern germplasm. Indigenous landraces with unique intermediate and admixed genetic backgrounds were untapped, representing valuable resources for rice breeding. Conclusions The genetic diversity of improved rice varieties has been substantially shaped by breeding goals, leading to differentiation between indica and japonica cultivars. Taiwanese landraces with different origins possess various and unique genetic backgrounds. Taiwanese rice germplasm provides diverse genetic variation for association mapping to unveil useful genes and is a precious genetic reservoir for rice improvement.

Biochemical Systematics, Biogeography and Evolutionary Rates in Species of the Mediterranean Genus Tyrrhenoleuctra (Plecoptera, Leuctridae)

2004 ◽  
Vol 35 (3) ◽  
pp. 299-306 ◽  
Author(s):  
◽  
J. M. Tierno de Figueroa ◽  
◽  
◽  
Keyword(s):  
North Africa ◽  
Evolutionary Rate ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Genetic Distances ◽  
Western Mediterranean ◽  
Similar Distribution ◽  
Undescribed Species ◽  
Vicariance Event ◽  
Definition Of

AbstractThe western Mediterranean stonefly genus Tyrrhenoleuctra traditionally includes 3 species: T. minuta (Spain, North Africa, Balearic Islands), T. tangerina (Spain, North Africa), T. zavattarii (Corsica and Sardinia). Since the traditional morphological characters display great and overlapping variation, allozyme electrophoresis was used to clarify taxonomic and phylogenetic relationships within the genus and to discuss biogeographical implications. The results clearly discriminate at least four entities: the Corso-Sardinian unit, for which the name T. zavattarii can be used; the Balearic population, representing an undescribed species; at least two Iberian peninsular species. However, more data on topotypic populations are needed to define the taxonomic status of the Iberian species (including definition of the currently used names T. minuta and T. tangerina). The presence of Tyrrhenoleuctra in Sardinia and Corsica is likely due to an old vicariance event following separation of the Sardinia-Corsica microplate from the Iberian Peninsula. Calibration of the molecular clock (genetic distances vs. Corso-Sardinian plate split from Iberia) resulted in a very low evolutionary rate (0.008 D/my), lower than those found in taxonomically distant groups (including stoneflies) with similar distribution.

scholarly journals A spectral theory for Wright’s inbreeding coefficients and related quantities

PLoS Genetics ◽  
2021 ◽  
Vol 17 (7) ◽  
pp. e1009665
Author(s):  
Olivier François ◽  
Clément Gain
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Population Genetic ◽  
Principal Component ◽  
Large Data ◽  
Population Subdivision ◽  
Adaptive Genetic Variation ◽  
Genomic Locus ◽  
Inbreeding Coefficients ◽  
Definition Of

Wright’s inbreeding coefficient, FST, is a fundamental measure in population genetics. Assuming a predefined population subdivision, this statistic is classically used to evaluate population structure at a given genomic locus. With large numbers of loci, unsupervised approaches such as principal component analysis (PCA) have, however, become prominent in recent analyses of population structure. In this study, we describe the relationships between Wright’s inbreeding coefficients and PCA for a model of K discrete populations. Our theory provides an equivalent definition of FST based on the decomposition of the genotype matrix into between and within-population matrices. The average value of Wright’s FST over all loci included in the genotype matrix can be obtained from the PCA of the between-population matrix. Assuming that a separation condition is fulfilled and for reasonably large data sets, this value of FST approximates the proportion of genetic variation explained by the first (K − 1) principal components accurately. The new definition of FST is useful for computing inbreeding coefficients from surrogate genotypes, for example, obtained after correction of experimental artifacts or after removing adaptive genetic variation associated with environmental variables. The relationships between inbreeding coefficients and the spectrum of the genotype matrix not only allow interpretations of PCA results in terms of population genetic concepts but extend those concepts to population genetic analyses accounting for temporal, geographical and environmental contexts.

Pharmacogenomics and Precision Psychiatry

2018 ◽  
pp. 96-102
Author(s):  
Julia C. Stingl ◽  
Gonzalo Laje
Keyword(s):  
Genetic Variation ◽  
Clinical Practice ◽  
Drug Therapy ◽  
Mechanisms Of Action ◽  
Molecular Medicine ◽  
Evidence Based ◽  
Broad Definition ◽  
Clinical Syndromes ◽  
Definition Of ◽  
Future Work

Molecular medicine has opened new possibilities of personalized approaches in drug therapy. The development of evidence-based pharmacogenetic guidelines to steer therapy has slowly entered the field of psychiatric therapeutics. Some of the reasons behind the limited progress in psychiatric pharmacogenomics include the broad definition of clinical syndromes, limited knowledge of psychiatric pathophysiology, and limited understanding of psychotropics’ mechanisms of action. Pharmacogenomic markers have been reported for both pharmacodynamic and pharmacokinetic genes. However, only genetic variation in pharmacokinetic genes has shown to be helpful in clinical practice. There is little consensus as to when and if pharmacogenetic tests should be used in psychiatry. There are limited evidence-based dosing guidelines available for actionable gene–drug pairs. Future work in psychiatry may deepen our understanding of the biological underpinnings of psychiatric syndromes and provide the potential for individual tailored therapies.

scholarly journals A new species of Anomaloglossus (Anura: Aromobatidae) of the stepheni group with the redescription of A. baeobatrachus (Boistel and de Massary, 1999), and an amended definition of A. leopardus Ouboter and Jairam, 2012

Zootaxa ◽  
2019 ◽  
Vol 4576 (3) ◽  
pp. 439 ◽  
Author(s):  
ANTOINE FOUQUET ◽  
JEAN-PIERRE VACHER ◽  
ELODIE A. COURTOIS ◽  
CHLOÉ DESCHAMPS ◽  
PAUL OUBOTER ◽  
...  
Keyword(s):  
New Species ◽  
Taxonomic Status ◽  
Species Group ◽  
Type Locality ◽  
Advertisement Call ◽  
Nominal Species ◽  
Guiana Shield ◽  
Group A ◽  
Breeding Mode ◽  
Definition Of

Anomaloglossus is a species-rich genus of frogs endemic to the Guiana Shield that still harbors several unnamed species. Within the A. stepheni species group (which includes four valid nominal species), A. baeobatrachus has an uncertain taxonomic status, notably because the holotype was an unvouchered specimen depicted in a popular journal. Another member of this group, A. leopardus, was only superficially described, lacking information on the sex of specimens in the type series and on advertisement call. Therefore, these two taxa need clarifications in order to allow the description of the extant undescribed species. In this paper, we redescribe A. baeobatrachus based on newly collected material from the species type locality and provide information about its reproductive ecology. We also provide an amended definition of A. leopardus using newly collected material from its type locality. These two species form a clade along with a third species from the Eastern Guiana Shield, which is also described herein. The reproductive biology of A. baeobatrachus and A. stepheni is very similar. Both species have endotrophic and nidicolous tadpoles, despite being distantly related, suggesting independent evolution of this breeding mode. The new species and A. leopardus, on the other hand, have exotrophic tadpoles. 

Taxonomic revision of the genus Eulimella (Gastropoda, Pyramidellidae) from Brazil, with description of three new species

Zootaxa ◽  
2011 ◽  
Vol 3063 (1) ◽  
pp. 22 ◽  
Author(s):  
ALEXANDRE DIAS PIMENTA ◽  
FRANKLIN NOEL DOS SANTOS ◽  
RICARDO SILVA ABSALÃO
Keyword(s):  
New Species ◽  
Taxonomic Status ◽  
Taxonomic Revision ◽  
Shell Morphology ◽  
Biological Information ◽  
Brazilian Coast ◽  
Similar Species ◽  
South American Species ◽  
Western Atlantic ◽  
Three New Species

A taxonomic revision of the pyramidellid genus Eulimella from Brazil was performed based on shell morphology. The holotype of Eulimella rudis Watson, 1886 is illustrated and compared to shells from the southeast Brazilian coast, this being the first confirmed record of this species after its original description. Eulimella smithii (Verrill, 1880), previously known from northern localities in the western Atlantic, is recorded from the southwestern Atlantic, along virtually the entire Brazilian coast; it is herein considered a distinct taxon from Eulimella unifasciata (Forbes, 1844), a very similar species from the eastern Atlantic, given the lack of data on development to consider an amphi-Atlantic distribution. Three new species are described: Eulimella torquata sp. nov., diagnosed by a constriction in the middle of each teleoconch whorl caused by a strong spiral furrow, producing a bilobed whorl profile; Eulimella cylindrata sp. nov., diagnosed by a large subcylindrical teleoconch; and Eulimella ejuncida sp. nov., characterized by its very slender shell, and small protoconch with only one whorl and with an “arc” shaped suture. The shells herein identified as Eulimella cf. calva from Brazil are conchologically identical to Eulimella calva Schander, 1994, from West Africa, but their taxonomic status should remain dubious because of lack of biological information to evaluate a possible amphi-Atlantic distribution pattern. All the species studied (except Eulimella ejuncida sp. nov.) have characteristic short microscopic axial threads organized in a spiral belt, varying in position and expression among species, but usually located in the middle of each teleoconch whorl or below the suture; this characteristic is also present in some species from the eastern Atlantic. Three South American species, originally or subsequently allocated in Eulimella, are herein considered as not belonging to this genus: Eulimella argentina Doello-Jurado, 1938; Eulimella bahiensis Castellanos, 1982; and Eulimella xenohyes (Melvill & Standen, 1912). The holotype of Eulimella lissa is illustrated with SEM micrographs.

scholarly journals Genetic Variability and Taxonomic Status of the Nihoa and Laysan Millerbirds

The Condor ◽  
2007 ◽  
Vol 109 (4) ◽  
pp. 954-962
Author(s):  
Robert C. Fleischer ◽  
Beth Slikas ◽  
Jon Beadell ◽  
Colm Atkins ◽  
Carl E. McINTOSH ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Microsatellite Loci ◽  
Sequence Divergence ◽  
Taxonomic Status ◽  
Small Population ◽  
Base Pairs ◽  
Stochastic Effects ◽  
Mtdna Sequence ◽  
Species Pairs ◽  
Two Populations

Abstract The Millerbird (Acrocephalus familiaris) is an endemic Northwestern Hawaiian Islands reed warbler that existed until about 1923 on Laysan Island (A. f. familiaris) and currently occurs in a small population on Nihoa Island (A. f. kingi). The two populations are described as separate subspecies or species on the basis of size and plumage differences. We assessed genetic variation in blood samples from 15 individuals in the modern Nihoa population using approximately 3000 base pairs (bp) of mitochondrial DNA (mtDNA) sequence and 14 microsatellite loci. We also obtained up to 1028 bp of mtDNA sequence from the fragmented DNA of museum specimens of three birds collected on Nihoa in 1923 and five birds collected on Laysan in 1902 and 1911 (ancient samples). Genetic variation in both marker types was extremely low in the modern Nihoa population (nucleotide diversity [π]  =  0.00005 for mtDNA sequences; observed heterozygosity was 7.2% for the microsatellite loci). In contrast, we found three mtDNA haplotypes among the five Laysan individuals (π  =  0.0023), indicating substantially greater genetic variation. The Nihoa and Laysan taxa differed by 1.7% uncorrected mtDNA sequence divergence, a magnitude that would support designation at the subspecies, and perhaps species, level relative to other closely related Acrocephalus species pairs. However, in light of strong ecological similarity between the two taxa, and a need to have additional populations to prevent extinction from stochastic effects and catastrophes, we believe these genetic differences should not deter a potential translocation of individuals from Nihoa to Laysan.

Taxonomic status of Protankyra ramiurna and Protankyra benedeni (Holothuroidea: Apodida: Synaptidae)

Zootaxa ◽  
2017 ◽  
Vol 4324 (3) ◽  
pp. 518 ◽  
Author(s):  
JÉSSICA PRATA ◽  
MICHELA BORGES ◽  
CYNTHIA L. C. MANSO ◽  
MARTIN LINDSEY CHRISTOFFERSEN
Keyword(s):  
Comparative Analysis ◽  
Taxonomic Status ◽  
Distinct Species ◽  
First Record ◽  
Brazilian Coast ◽  
Single Variable ◽  
Variable Species

This study presents a review of the species Protankyra ramiurna Heding, 1928 and Protankyra benedeni (Ludwig, 1881) from the Brazilian coast. Some authors consider that these two taxa represent a single variable species. Our comparative analysis of external characters, anatomy and ossicle morphology indicates that they represent distinct species. This is the first record of Protankyra ramiurna from Brazil. 

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