scholarly journals Morphological characters and SNP markers suggest hybridization and introgression in sympatric populations of the pleurocarpous mosses Homalothecium lutescens and H. sericeum

2020 ◽  
Vol 20 (4) ◽  
pp. 619-637
Author(s):  
Weerachon Sawangproh ◽  
Annick S. Lang ◽  
Lars Hedenäs ◽  
Nils Cronberg
Keyword(s):  
Morphological Characters ◽  
Snp Markers ◽  
Transcriptome Data ◽  
Sympatric Populations ◽  
Future Studies ◽  
Evolutionary Diversification ◽  
Allopatric Populations ◽  
Intermediate Morphology ◽  
Pleurocarpous Mosses

AbstractHybridization in bryophytes involves a fusion of gametes produced by haploid parental gametophytes of different species. The primary hybrid is thus the short-lived diploid sporophyte, which soon undergoes meiosis prior to the formation of large amounts of haploid spores. We compared morphology of gametophytes (branch leaves) and sporophytes (capsule inclination) from sympatric populations and allopatric populations of H. lutescens and H. sericeum. In addition, we used transcriptome data to select 85 nuclear SNP markers that were fixed for alternative alleles in the two species. The SNPs were used to estimate the degree of hybridization in diploid sporophytes. Our study shows that gametophytes from sympatric populations display intermediate morphology in a number of leaf characters, with exception for leaf sizes, which are markedly smaller than those in allopatric populations. None of the 100 sporophytes appeared to be primary hybrids, but 33 displayed admixing—heterozygotic expression of SNP markers or mismatch of occasional markers in homozygous condition—suggesting that extensive introgression takes place in the sympatric populations. Most sporophytes with intermediate capsule inclination, initially classed as putative hybrids, did not display admixture of nuclear SNP markers. Sixty-seven percent of admixed sporophytes have predominantly nuclear SNPs typical for H. lutescens. Our results suggest that interspecific hybridization and bidirectional introgression are relatively common in the studied sympatric populations, giving rise to viable recombinants, but not complete mixing of the parental genomes. Our study is one of the first detailed accounts of hybridization among pleurocarpous mosses, opening for future studies of gene transfer and introgression between bryophyte lineages and its role in local adaptation and long-term evolutionary diversification.

Lack of morphological differentiation in eastern (Rhinichthys atratulus) and western (Rhinichthys obtusus) blacknose dace in Canada

2005 ◽  
Vol 83 (11) ◽  
pp. 1502-1509 ◽  
Author(s):  
B A Fraser ◽  
N E Mandrak ◽  
R L McLaughlin
Keyword(s):  
Multivariate Analyses ◽  
Morphological Differentiation ◽  
Morphological Characters ◽  
Sympatric Populations ◽  
Diagnostic Characters ◽  
Allopatric Populations ◽  
Rhinichthys Atratulus ◽  
Blacknose Dace ◽  
Morphological Differences ◽  
Colouration Pattern

We tested whether eastern (Rhinichthys atratulus (Herman, 1804)) and western (Rhinichthys obtusus Agassiz, 1854) blacknose dace could be differentiated in Canada. Eastern, western, and southern forms of blacknose dace had been considered subspecies until recently, when separation of eastern and western species was accepted (J.S. Nelson et al. 2004. Am. Fish. Soc. Spec. Publ. No. 29). However, no study has examined morphological differences in purported diagnostic characters between the two species in Canada. Mensural, meristic, and colouration pattern characters purported to distinguish the two species were measured for blacknose dace across their Canadian range, including likely zones of sympatry. Univariate and multivariate analyses of morphological characters could not distinguish between individuals in allopatric populations from eastern and western regions. Variation among individuals within sympatric populations did not differ significantly from the variation among individuals within allopatric populations, providing no evidence of divergence of the species in sympatry. The delineation of eastern and western species using morphology is not supported by this study, given the lack of differentiation in key distinguishing characters within the Canadian range of the species.

scholarly journals Mitochondrial patterns of intra- and interspecific differentiation among endemic freshwater crabs of ancient lakes in Sulawesi

2008 ◽  
Vol 77 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Christoph D. Schubart ◽  
Tobias Santl ◽  
Peter Koller
Keyword(s):  
Gene Segment ◽  
Morphological Characters ◽  
Ancient Lakes ◽  
Ecological Stability ◽  
Sequence Identity ◽  
Allopatric Populations ◽  
Freshwater Crabs ◽  
Local Endemic ◽  
Characteristic Features

Due to their long-term ecological stability, ancient lakes represent very interesting systems for studying differentiation and speciation processes. High degrees of endemism and specialisation are characteristic features of their fauna. The Malili lakes from the Indonesian island Sulawesi are considered an ancient limnic system, and recent research has increased the number of recognized species and the knowledge about ecological and morphological diversification within a variety of animal taxa. Here we show that the local endemic gecarcinucid freshwater crabs are more differentiated than qualitative morphological characters and the current taxonomy may indicate. The morphologically and ecologically well characterised species Nautilothelphusa zimmeri Balss, 1933 consists of two allopatric populations with one of the groups being more closely related to sympatric Parathelphusa ferruginea Chia and Ng, 2006 according to mitochondrial genetic data. One haplotype is even shared by both species. Nevertheless, in this study lack of gene flow between both species is demonstrated. To our knowledge, this is the first report of DNA sequence identity between two different genera along the same cytochrome oxidase I gene segment that is being proposed for barcoding studies.

scholarly journals Genome size and phenotypic variation of Nymphaea (Nymphaeaceae) species from Eastern Europe and temperate Asia

2015 ◽  
Vol 84 (2) ◽  
pp. 277-286 ◽  
Author(s):  
Magdalena Anna Dąbrowska ◽  
Kaja Rola ◽  
Polina Volkova ◽  
Jan Suda ◽  
Joanna Zalewska-Gałosz
Keyword(s):  
Eastern Europe ◽  
Genome Size ◽  
Phenotypic Variation ◽  
Morphological Characters ◽  
Natural Hybridization ◽  
Hybrid Individual ◽  
Intermediate Morphology ◽  
Temperate Asia ◽  
Species Specific

Despite long-term research, the aquatic genus <em>Nymphaea</em> still possesses major taxonomic challenges. High phenotypic plasticity and possible interspecific hybridization often make it impossible to identify individual specimens. The main aim of this study was to assess phenotypic variation in <em>Nymphaea</em> taxa sampled over a wide area of Eastern Europe and temperate Asia. Samples were identified based on species-specific genome sizes and diagnostic morphological characters for each taxon were then selected. A total of 353 specimens from 32 populations in Poland, Russia and Ukraine were studied, with nine biometric traits being examined. Although some specimens morphologically matched <em>N. ×borealis</em> (a hybrid between <em>N. alba</em> and <em>N. candida</em>) according to published determination keys, only one hybrid individual was revealed based on genome size data. Other specimens with intermediate morphology possessed genome size corresponding to <em>N. alba</em>, <em>N. candida</em> or <em>N. tetragona</em>. This indicates that natural hybridization between <em>N. alba</em> and <em>N. candida</em> is not as frequent as previously suggested. Our results also revealed a considerably higher variation in the studied morphological traits (especially the quantitative ones) in <em>N. alba</em> and <em>N. candida</em> than reported in the literature. A determination key for the investigated <em>Nymphaea</em> species is provided, based on taxonomically-informative morphological characters identified in our study.

scholarly journals Intra- and interspecific morphological variation in sympatric and allopatric populations of Mustela putorius and M. eversmanii (Carnivora: Mustelidae) and detection of potential hybrids

2020 ◽  
Author(s):  
Tamás Cserkész ◽  
Csaba Kiss ◽  
Zoltán Barkaszi ◽  
Tamás Görföl ◽  
Igor Zagorodniuk ◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Morphological Differentiation ◽  
Morphological Characters ◽  
Cranial Morphology ◽  
Mustela Putorius ◽  
Sympatric Populations ◽  
Representative Sampling ◽  
Allopatric Populations ◽  
Morphometric Analyses ◽  
Cranial Measurements

Abstract European mustelids include the European polecat, Mustela putorius, and the steppe polecat, M. eversmanii. Both occur sympatrically in the Pannonian Basin, where M. eversmanii hungarica represents the westernmost part of the latter species and they allegedly hybridize. We investigated the morphological relationships in sympatric and allopatric populations of these mustelids with representative sampling, taxonomic and geographic coverage. We evaluated inter- and intraspecific patterns of morphological differentiation of 20 cranial measurements and four external traits by distance-based morphometric approaches and multivariate analyses. Our results revealed a considerable heterogeneity in cranial morphology. The two species appeared to be clearly differentiated although sympatric populations were closer to each other and had a slight overlap in the morphometric space. Within M. eversmanii, the subspecies and the nominal taxon only partially overlapped, and M. eversmanii eversmanii was more distant from M. putorius than subspecies hungarica. Although morphometric analyses revealed several intermediate individuals in size in sympatric M. eversmanii and M. putorius populations, only a small fraction of such specimens showed conflict in discrete morphological characters with the diagnostic discriminant function. We interpret these results as an indication of ongoing hybridisation between sympatric populations, but the low number of hybrids identified suggests limited genetic exchange between the species.

Integrative taxonomic and geographic variation analyses in Cyrtodactylus aequalis (Squamata: Gekkonidae) from southern Myanmar (Burma): one species, two different stories

2020 ◽  
Vol 66 (3-4) ◽  
pp. 151-179
Author(s):  
L. Lee Grismer ◽  
L. Wood Perry ◽  
Marta S. Grismer ◽  
Evan S.H. Quah ◽  
Myint Kyaw Thura ◽  
...  
Keyword(s):  
Geographic Variation ◽  
Evolutionary History ◽  
Phylogenetic Inference ◽  
Morphological Characters ◽  
Molecular Data ◽  
Biodiversity Crisis ◽  
Allopatric Populations ◽  
Compelling Argument ◽  
Historical Accuracy ◽  
Molecular Phylogenetic

The historical accuracy of building taxonomies is improved when they are based on phylogenetic inference (i.e., the resultant classifications are less apt to misrepresent evolutionary history). In fact, taxonomies inferred from statistically significant diagnostic morphological characters in the absence of phylogenetic considerations, can contain non-monophyletic lineages. This is especially true at the species level where small amounts of gene flow may not preclude the evolution of localized adaptions in different geographic areas while underpinning the paraphyletic nature of each population with respect to the other. We illustrate this point by examining genetic and morphological variation among three putatively allopatric populations of the granite-dwelling Bent-toed Gecko Cyrtodactylus aequalis from hilly regions in southeastern Myanmar. In the absence of molecular phylogenetic inference, a compelling argument for three morphologically diagnosable species could be marshaled. However, when basing the morphological analyses of geographic variation on a molecular phylogeny, there is a more compelling argument that only one species should be recognized. We are cognizant of the fact however, that when dealing with rare species or specimens for which no molecular data are possible, judicious morphological analyses are the only option—and the desired option given the current worldwide biodiversity crisis.

Evidence-Based Cognitive Rehabilitation for People With Multiple Sclerosis: A Systematic Review

2021 ◽  
Vol 75 (Supplement_2) ◽  
pp. 7512520385p1-7512520385p1
Author(s):  
Yu-Chih Chen ◽  
Szu-Wei Chen ◽  
Britney Ferri
Keyword(s):  
Processing Speed ◽  
Cognitive Skills ◽  
Cognitive Rehabilitation ◽  
Evidence Based ◽  
Long Term Outcomes ◽  
Noninvasive Brain Stimulation ◽  
Future Studies ◽  
Cognitive Improvement ◽  
Computer Based

Abstract Date Presented 04/22/21 Computer-based programs, conventional cognitive rehabilitation, neurologic music therapy, and noninvasive brain stimulation are effective in improving memory and learning, processing speed, language, executive function, or general cognitive skills. However, the retention of treatment effects and the generalizability of the cognitive improvement to the daily occupations are not clear. Including a predetermined single outcome, functional and long-term outcomes are needed in future studies. Primary Author and Speaker: Yu-Chih Chen Contributing Authors: Nicole Gerhardt, Christina Calhoun Thielen, Winnie Dunn, and Mary Jane Mulcahey

scholarly journals Intrinsic vs. Extrinsic Motivation as Drivers for Early Engagement in Research by Medical Students

2020 ◽  
Author(s):  
Yassar Alamri ◽  
Erik Monasterio ◽  
Lutz Beckert ◽  
Tim J Wilkinson
Keyword(s):  
Medical Students ◽  
Extrinsic Motivation ◽  
Self Determination Theory ◽  
Self Determination ◽  
Future Studies ◽  
Research Engagement ◽  
Research Activities ◽  
Research Involvement ◽  
Key Factor

Abstract BackgroundA student’s motivation is a key factor in their success in undertaking an education endeavour. However, how this relates to involvement in research by medical students is unclear.MethodsAn electronic questionnaire was sent to all medical students at our institution. To ascertain students’ motivation to undertake research, they were asked an open-ended question to describe the single major factor that would encourage them to get involved in research as a medical student. A framework of self-determination theory was used to deductively code the responses as intrinsic motivation (‘IM’; e.g., interest/passion) or extrinsic motivation (‘EM’; e.g. improving CV). The two groups were then contrasted in relation to their research engagement.ResultsA total of 348 students were included in the survey, of whom 204 were coded as IM responses, and 144 were coded as EM responses. Students who engaged in extra-curricular research activities were more likely to report an underlying EM (48% vs. 36%, p = 0.03). They were also older (23.7 ± 3.5 vs. 21.9 ± 3.7, p = 0.005), and more likely to have completed a prior research degree (15% vs. 3%, p = 0.01).ConclusionIn this study, EM was a bigger influencer on research involvement by medical students than IM. Future studies should explore promoters of IM, and include longitudinal data in order to assess whether EM students continue to be involved in research long-term.

scholarly journals Dual orexin receptor antagonist in treatment of insomnia

Engrami ◽  
2020 ◽  
Vol 42 (2) ◽  
pp. 57-68
Author(s):  
Nikola Trajanović
Keyword(s):  
Circadian Rhythm ◽  
Side Effects ◽  
Receptor Antagonist ◽  
Safety Profile ◽  
The Elderly ◽  
First Line ◽  
Future Studies ◽  
Good Safety Profile ◽  
Circadian Rhythm Disorders

A novel group of medications, dual orexin receptor antagonists, emerged as a competent group that challenges current first-line hypnotics. They have relatively infrequent and mostly well-tolerated side effects, primarily in the form of residual somnolence, fatigue and nightmares/disturbing dreams. The advantage over conventional hypnotics stems from the specifics of their target receptors, which translates into lack of tolerance after long term use and good safety profile. They are particularly favoured in some specific populations, including the elderly. Ongoing and future studies are set to explore their effect on selected conditions, such as addiction and psychiatric disorders, dementias, perimenopausal condition and circadian rhythm disorders, to name a few.

scholarly journals Photoacoustic spectroscopy allows to make correlations between blood p450 cytochrome and glycemia in type 1 experimental diabetes

2021 ◽  
Vol 2090 (1) ◽  
pp. 012152
Author(s):  
L I Olvera ◽  
G C Villanueva ◽  
E Romero ◽  
A Cruz
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Diabetes Complications ◽  
Venous Blood ◽  
Future Studies ◽  
Patients With Diabetes ◽  
Male Wistar Rats ◽  
Experimental Type ◽  
Non Destructive

Abstract Diabetes is the eight-cause death worldwide. The cause of death of patients with diabetes is mostly the long-term complications, that are not easy to detect opportunely. In previous studies, we applied photoacoustic spectroscopy (PAS), a non-destructive technique, to detect several components of blood. The goal of the study was to apply the phase-resolved method (PRM), on blood optical absorption spectra obtained by PAS, to analyse blood components in experimental type 1 diabetes. Diabetes was produced in male Wistar rats through the administrations of streptozotocin (STZ). Venous blood samples were obtained one, two, four and eight weeks after STZ. PRM applied to spectra allowed to detect p450 cytochrome. There was a significant and positive correlation between glycaemia and p450 cytochrome (p=0.001). Since p450 cytochrome participates in detoxification function, results indicate that glycaemia could affect detoxification. It will be important in future studies to study the implications of those results on the development of diabetes complications. The novelty of the study was to use PAS to find out if there was any correlation between spectroscopy variables and glycaemia. It is concluded that PRM applied to PAS is a suitable technology to study p450 cytochrome in diabetes.

scholarly journals The identity of Erica flavisepala

Bothalia ◽  
1977 ◽  
Vol 12 (2) ◽  
pp. 195-197
Author(s):  
E. G. H. Oliver
Keyword(s):  
Morphological Characters ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Sympatric Populations

The recording of a few scattered plants of  E. flavisepala Guth. Bol. among sympatric populations of two other species led to a comparison of their morphological characters. From this comparison a putative hybrid origin was indicated, thus  E. x  flavisepala Guth. Bol.=E.  thunbergii Montin  X  E. sphaerocephala Wendl.

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