High molecular diversity in the Carabus variolosus/nodulosus complex

Starting point of this study was the problem considering the status of Carabus variolous and C. nodulosus: French and some German authors classified them as species, most German authors as subspecies and Casale as semispecies. We performed analyses of mitochondrial genes (COI-5', COI-3', ND5) as well as nuclear ones (ITS2, wingless) and analysed the DNA sequences using Seqotron, CLUSTALX (editing and alignment), MEGA, DNAML, SplitsTree (phylogeny and network), 4SALE (compensatory base changes), and BEAST (coalescence). We could study specimens from all regions except the western most part of the distribution area (Massif Central and French Jura, France). The mitochondrial DNA data resulted in a geographic pattern of high diversity within both taxa indicating a series of glacial refuges. In addition, a considerably large area was found were introgressive hybridisation took place in the past - at least two times by nodulosus of different regions into variolosus. The nuclear DNA data show a clear and constant difference between both taxa. In consequence, this complex of forms may be characterised as semispecies from an evolutionary viewpoint but taxonomically as one species because of hybridisation and the lack of compensatory bases changes.

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Genome size in natural and synthetic autopolyploids and in a natural segmental allopolyploid of several Triticeae species

Genome ◽

10.1139/g09-004 ◽

2009 ◽

Vol 52 (3) ◽

pp. 275-285 ◽

Cited By ~ 28

Author(s):

T. Eilam ◽

Y. Anikster ◽

E. Millet ◽

J. Manisterski ◽

M. Feldman

Keyword(s):

Genome Size ◽

Dna Sequences ◽

Nuclear Dna ◽

Reduction Process ◽

Distribution Area ◽

Meiotic Pairing ◽

Dna Amount ◽

Similar Reduction ◽

Nuclear Dna Amount ◽

Hordeum Murinum

Nuclear DNA amount (1C) was determined by flow cytometry in the autotetraploid cytotype of Hordeum bulbosum , in the cytologically diploidized autotetraploid cytotypes of Elymus elongatus , Hordeum murinum subsp. murinum and Hordeum murinum subsp. leporinum, in Hordeum marinum subsp. gussoneanum, in their progenitor diploid cytotypes, and in a newly synthesized autotetraploid line of E. elongatus. Several lines collected from different regions of the distribution area of every taxon, each represented by a number of plants, were analyzed in each taxon. The intracytotype variation in nuclear DNA amount of every diploid and autotetraploid cytotype was very small, indicating that no significant changes have occurred in DNA amount either after speciation or after autopolyploid formation. The autotetraploid cytotypes of H. bulbosum and the cytologically diploidized H. marinum subsp. gussoneanum had the expected additive amount of their diploid cytotypes. On the other hand, the cytologically diploidized autotetraploid cytotypes of E. elongatus and H. murinum subsp. murinum and H. murinum subsp. leporinum had considerably less nuclear DNA (10%–23%) than the expected additive value. Also, the newly synthesized autotetraploid line of E. elongatus showed similar reduction in DNA as its natural counterpart, indicating that the reduction in genome size occurred in the natural cytotype during autopolyploidization. It is suggested that the diploid-like meiotic behavior of these cytologically dipolidized autotetraploids is caused by the instantaneous elimination of a large number of DNA sequences, different sequences from different homologous pairs, leading to differentiation of the constituent genomes. The eliminated sequences are likely to include those that participate in homologous recognition and initiation of meiotic pairing. A gene system determining exclusive bivalent pairing by utilizing the differentiation between the two groups of homologues has been presumably superimposed on the DNA reduction process.

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Evaluating taxonomic inflation: towards evidence-based species delimitation in Eurasian vipers (Serpentes: Viperinae)

Amphibia-Reptilia ◽

10.1163/15685381-bja10007 ◽

2020 ◽

Vol 41 (3) ◽

pp. 285-311 ◽

Cited By ~ 4

Author(s):

Inês Freitas ◽

Sylvain Ursenbacher ◽

Konrad Mebert ◽

Oleksandr Zinenko ◽

Silke Schweiger ◽

...

Keyword(s):

Dna Sequences ◽

Nuclear Dna ◽

Morphological Data ◽

Valid Species ◽

Evidence Based ◽

Species Status ◽

Species Complexes ◽

As Species ◽

Considerable Controversy ◽

Low Levels

Abstract The designation of taxonomic units has important implications for the understanding and conservation of biodiversity. Eurasian vipers are a monophyletic group of viperid snakes (Serpentes, Viperinae), currently comprising four genera (Daboia, Macrovipera, Montivipera and Vipera) and up to 40 species. Taxonomic units have been described using a wide variety of methods and criteria, and consequently, considerable controversy still surrounds the validity of some currently listed species. In order to promote a consensus- and evidence-based taxonomy of Eurasian vipers, we analysed published mitochondrial and nuclear DNA sequences for this group to reconstruct phylogenetic relationships among currently recognized viper species. We also compiled information on external morphology to assess their morphological distinctiveness. Phylogenetic inference based on mtDNA sequences shows contrasting levels of divergence across genera and species and identifies several instances of non-monophyly in described species. Nuclear DNA sequences show extremely low levels of genetic variation, with a widespread pattern of allele sharing among distant species, and even among genera. Revision of morphological data shows that most species designations rely on scalation traits that overlap extensively among species of the same genus. Based on our combined assessment, we recognize 15 taxa as valid species, three taxa which likely represent species complexes, 17 taxa of doubtful validity as species, and five taxa for which species status is maintained but further research is highly recommended to assess taxonomic arrangements. We stress the need to implement integrative taxonomic approaches for the recognition of evidence-based taxonomic units in Eurasian vipers.

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A new species of Mexican parrot? Reasonable doubt on the status of Amazona gomezgarzai (Psittaciformes: Psittacidae)

Zootaxa ◽

10.11646/zootaxa.4420.1.9 ◽

2018 ◽

Vol 4420 (1) ◽

pp. 139

Author(s):

PATRICIA ESCALANTE ◽

ABIGAIL EUNICE ARTEAGA-ROJAS ◽

MAURICIO GUTIÉRREZ-SÁNCHEZ-RÜED

Keyword(s):

New Species ◽

Nuclear Dna ◽

Yucatan Peninsula ◽

Reasonable Doubt ◽

Hybrid Origin ◽

Valid Species ◽

Distribution Area ◽

Yucatán Peninsula ◽

Original Manuscript ◽

The Status

We present arguments against the recognition of Amazona gomezgarzai Silva et al., 2017 as a valid species. This putative new species was stated to have been discovered in Becanchén town in the central Yucatan Peninsula by a veterinarian, who presented two live individuals to the authors for description. This description has numerous weaknesses, as follows: 1) the Yucatan Peninsula avifauna is well-known, having been extensively explored by collectors and other ornithologists; 2) the authors were never in the relevant field area, nor did they verify that the two individuals obtained for the description came from a natural population; 3) our field trip to the type locality and distribution area failed to verify the existence of the putative new species there; instead, inhabitants of these localities denied that such a person was there and denied having given anyone the birds, nor did they recognize that there were parrots matching the “new” species in the area; 4) the description was prepared without proper voucher specimens; 5) comparisons in existing museum collections were highly inadequate; 6) the characters on which the description is based fail to support that it represents a valid taxon, instead strongly supporting an hypothesis of hybrid origin, which was untested by nuclear DNA markers; and 7) no collecting permits were mentioned in the paper. Although earlier reviewers pointed out weaknesses of the original manuscript, the authors failed to rigorously address these questions and the paper was nevertheless published.

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Evidence for genetic hybridization between Ixodes scapularis and Ixodes cookei

Canadian Journal of Zoology ◽

10.1139/cjz-2016-0134 ◽

2017 ◽

Vol 95 (8) ◽

pp. 527-537 ◽

Cited By ~ 7

Author(s):

James W. Patterson ◽

Anna M. Duncan ◽

Kelsey C. McIntyre ◽

Vett K. Lloyd

Keyword(s):

Mitochondrial Dna ◽

Genetic Analysis ◽

New Brunswick ◽

Nuclear Dna ◽

Ixodes Scapularis ◽

Companion Animals ◽

Genetic Introgression ◽

Eastern Canada ◽

As Species ◽

Intermediate Traits

Ixodes scapularis Say, 1821 (the black-legged tick) is becoming established in Canada. The northwards expansion of I. scapularis leads to contact between I. scapularis and Ixodes cookei Packard, 1869, a well-established tick species in Eastern Canada. Examination of I. cookei and I. scapularis collected from New Brunswick revealed ticks with ambiguous morphologies, with either a mixture or intermediate traits typical of I. scapularis and I. cookei, including in characteristics typically used as species identifiers. Genetic analysis to determine if these ticks represent hybrids revealed that four had I. cookei derived mitochondrial DNA but I. scapularis nuclear DNA. In one case, the nuclear sequence showed evidence of heterozygosity for I. scapularis and I. cookei sequences, whereas in the others, the nuclear DNA appeared to be entirely derived from I. scapularis. These data strongly suggest genetic hybridization between these two species. Ixodes cookei and hybrid ticks were readily collected from humans and companion animals and specimens infected with Borrelia burgdorferi Johnson et al., 1984, the causative agent of Lyme disease, were identified. These findings raise the issue of genetic introgression of I. scapularis genes into I. cookei and warrant reassessment of the capacity of I. cookei and I. cookei × I. scapularis hybrids to vector Borrelia infection.

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Reconciling Loss Aversion and Gain Seeking in Judged Emotions

Current Directions in Psychological Science ◽

10.1177/0963721421992043 ◽

2021 ◽

pp. 096372142199204

Author(s):

Barbara A. Mellers ◽

Siyuan Yin ◽

Jonathan Z. Berman

Keyword(s):

Loss Aversion ◽

Reference Point ◽

Emotional Reactions ◽

Status Quo ◽

New Approach ◽

Negative Change ◽

Starting Point ◽

The Status ◽

Positive Feelings ◽

Negative Feelings

Is the pain of a loss greater in magnitude than the pleasure of a comparable gain? Studies that compare positive feelings about a gain with negative feelings about a comparable loss have found mixed answers to this question. The pain of a loss can be greater than, less than, or equal to the pleasure of a comparable gain. We offer a new approach to test hedonic loss aversion. This method uses emotional reactions to the reference point, a positive change, and a negative change. When we manipulated the reference point (i.e., pleasurable and painful), two distinct patterns emerged. Pain surpassed pleasure (loss aversion) when the reference point was positive, and pleasure exceeded pain (gain seeking) when the reference point was negative. A reference-dependent version of prospect theory accounts for the results. If the carriers of utility are changes from a reference point—not necessarily the status quo—both loss aversion and gain seeking are predicted. Loss aversion and gain seeking can be reconciled if you take the starting point into account.

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Bioinvasions of the Medfly Ceratitis capitata: Source Estimation Using DNA Sequences at Multiple Intron Loci

Genetics ◽

10.1093/genetics/153.1.351 ◽

1999 ◽

Vol 153 (1) ◽

pp. 351-360 ◽

Cited By ~ 3

Author(s):

Neil Davies ◽

Francis X Villablanca ◽

George K Roderick

Keyword(s):

Population Structure ◽

Latin America ◽

Dna Sequences ◽

Ceratitis Capitata ◽

Fruit Fly ◽

Ecological Processes ◽

The Status ◽

Considerable Controversy ◽

Source Populations ◽

Traditional Population

Abstract The Mediterranean fruit fly, Ceratitis capitata, is a devastating agricultural pest that threatens to become established in vulnerable areas such as California and Florida. Considerable controversy surrounds the status of Californian medfly infestations: Do they represent repeated introductions or the persistence of a resident population? Attempts to resolve this question using traditional population genetic markers and statistical methods are problematic because the most likely source populations in Latin America were themselves only recently colonized and are genetically very similar. Here, significant population structure among several New World medfly populations is demonstrated through the analysis of DNA sequence variation at four intron loci. Surprisingly, in these newly founded populations, estimates of population structure increase when measures of subdivision take into account the relatedness of alleles as well as their frequency. A nonequilibrium, likelihood-based statistical test that utilizes multilocus genotypes suggests that the sole medfly captured in California during 1996 was introduced from Latin America and was less likely to be a remnant of an ancestral Californian population. Many bioinvasions are hierarchical in nature, consisting of several sequential or overlapping invasion events, the totality of which can be termed a metainvasion. Phylogenetic data from multilocus DNA sequences will be vital to understanding the evolutionary and ecological processes that underlie metainvasions and to resolving their constituent levels.

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