scholarly journals Phylogeny and species differentiation of four wild almond species of subgen. Amygdalus in China

2021 ◽  
Vol 45 (9) ◽  
pp. 987-995
Author(s):  
Chun-Cheng WANG ◽  
Yun-Ling ZHANG ◽  
Song-Mei MA ◽  
Gang HUANG ◽  
Dan ZHANG ◽  
...  
Keyword(s):  
Species Differentiation ◽  
Wild Almond

scholarly journals Surprising Drought Tolerance of Fir (Abies) Species between Past Climatic Adaptation and Future Projections Reveals New Chances for Adaptive Forest Management

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 821
Author(s):  
Csaba Mátyás ◽  
František Beran ◽  
Jaroslav Dostál ◽  
Jiří Čáp ◽  
Martin Fulín ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Test Site ◽  
Species Differentiation ◽  
Silver Fir ◽  
Growth And Survival ◽  
Future Performance ◽  
Moisture Deficit ◽  
Climatic Scenarios ◽  
Unique Potential

Research Highlights: Data of advanced-age provenance tests were reanalyzed applying a new approach, to directly estimate the growth of populations at their original sites under individually generated future climates. The results revealed the high resilience potential of fir species. Background and Objectives: The growth and survival of silver fir under future climatic scenarios are insufficiently investigated at the xeric limits. The selective signature of past climate determining the current and projected growth was investigated to analyze the prospects of adaptive silviculture and assisted transfer of silver fir populations, and the introduction of non-autochthonous species. Materials and Methods: Hargreaves’ climatic moisture deficit was selected to model height responses of adult populations. Climatic transfer distance was used to assess the relative drought stress of populations at the test site, relating these to the past conditions to which the populations had adapted. ClimateEU and ClimateWNA pathway RCP8.5 data served to determine individually past, current, and future moisture deficit conditions. Besides silver fir, other fir species from South Europe and the American Northwest were also tested. Results: Drought tolerance profiles explained the responses of transferred provenances and predicted their future performance and survival. Silver fir displayed significant within-species differentiation regarding drought stress response. Applying the assumed drought tolerance limit of 100 mm relative moisture deficit, most of the tested silver fir populations seem to survive their projected climate at their origin until the end of the century. Survival is likely also for transferred Balkan fir species and for grand fir populations, but not for the Mediterranean species. Conclusions: The projections are less dramatic than provided by usual inventory assessments, considering also the resilience of populations. The method fills the existing gap between experimentally determined adaptive response and the predictions needed for management decisions. It also underscores the unique potential of provenance tests.

Intraspecific variability of morphological characters in the species-rich deep-sea genus Acantholaimus Allgén, 1933 (Nematoda: Chromadoridae)

Nematology ◽  
2016 ◽  
Vol 18 (4) ◽  
pp. 455-473 ◽  
Author(s):  
Dmitry M. Miljutin ◽  
Maria A. Miljutina
Keyword(s):  
Deep Sea ◽  
Intraspecific Variability ◽  
Morphological Characters ◽  
Molecular Data ◽  
Species Discrimination ◽  
Species Differentiation ◽  
Lateral Field ◽  
Operational Taxonomic Units ◽  
General Arrangement ◽  
Taxonomic Approach

Acantholaimusis a species-rich genus of deep-sea nematodes, often with dozens of species found at the same locality but each represented by single or few individuals. Species discrimination by morphological characters in this genus is therefore often difficult due to transitional forms that may be referred to several species because of lack of data on intraspecific variability. The aim of this study was to evaluate the intraspecific variability of morphological characters that are most often used inAcantholaimustaxonomy, in order to distinguish those which are most informative for species differentiation. A reverse taxonomic approach was applied for initial species discrimination. Two loci, one each from small and large subunits of rRNA, were sequenced for 59Acantholaimusspecimens from two deep-sea locations. Twenty-seven Molecular Operational Taxonomic Units (MOTU) were identified, of which 12 were represented by more than one individual. These were then analysed for intraspecific variability in morphological characters. Some of the examined characters showed high intraspecific variability; specifically: length of cephalic setae; distance from anterior end to amphid; shape of anterior setae; position and arrangement of cervical setae. In the absence of genetic data, these characters should be used with caution for differential diagnoses or species discrimination. Other characters were more conservative within the same MOTU: body proportions; length of outer labial setae; amphidial diam.; appearance of lateral field; general arrangement of cervical setae; and shape of tail. These characters may be successfully used for species discrimination in the absence of molecular data.

ISSR Marker Based Genetic Diversity in Morinda Spp. For Its Enhanced Collection, Conservation and Utilization

2021 ◽  
Author(s):  
Lalit Arya ◽  
Ramya Kossery Narayanan ◽  
Anjali Kak ◽  
Chitra Devi Pandey ◽  
Manjusha Verma ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Diversity ◽  
Inter Simple Sequence Repeat ◽  
Issr Markers ◽  
Morinda Citrifolia ◽  
Species Differentiation ◽  
Information Index ◽  
Upgma Cluster Analysis ◽  
Simple Sequence

Abstract Morinda (Rubiaceae) is considerably recognized for its multiple uses viz. food, medicine, dyes, firewood, tools, oil, bio-sorbent etc. The molecular characterization of such an important plant would be very useful for its multifarious enhanced utilization. In the present study, 31 Morinda genotypes belonging to two different species Morinda citrifolia and Morinda tomentosa collected from different regions of India were investigated using Inter Simple Sequence Repeat (ISSR) markers. Fifteen ISSR primers generated 176 bands with an average of 11.7 bands per primer, of which (90.34%) were polymorphic. The percentage of polymorphic bands, mean Nei’s gene diversity, mean Shannon’s information index in Morinda tomentosa and Morinda citrifolia was [(69.89%, 30.68%); (0.21 ± 0.19, 0.12 ± 0.20); (0.32 ± 0.27 0.17 ± 0.28)] respectively, revealing higher polymorphism and genetic diversity in Morinda tomentosa compared to Morinda citrifolia. Structure, and UPGMA cluster analysis placed the genotypes into well-defined separate clusters belonging to two species Morinda tomentosa and Morinda citrifolia revealing the utility of ISSR markers in species differentiation. Distinct ecotypes within a particular species could also be inferred emphasizing the collection and conservation of Morinda genotypes from different regions, in order to capture the overall diversity of respective species. Further higher diversity of M. tomentosa must be advanced for its utilization in nutraceutical, nutritional and other nonfood purposes.

scholarly journals Radular ultrastructure of South American Ampullariidae (Gastropoda: Prosobranchia)

2007 ◽  
Vol 67 (4) ◽  
pp. 721-726 ◽  
Author(s):  
SM Martín ◽  
LHL Negrete
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Pomacea Canaliculata ◽  
Species Differentiation ◽  
South American ◽  
Central Tooth ◽  
Scanning Electron

The radula of five species of South American Ampullariidae was analysed by Scanning Electron Microscope (SEM) with the purpose of enlarging new studies on the systematic of this family. The studied species were Pomacea -canaliculata (Lamarck, 1822), Pomacea scalaris (d'Orbigny, 1835), Pomella (P.) megastoma (Gray, 1847), Asolene (A.) platae (Maton, 1809) and Felipponea neritiniformis (Dall, 1919). The central tooth shows different attributes which provide the means for generic determination; the analysis of the central tooth, the lateral and marginal ones by SEM adds further information for species differentiation.

scholarly journals Interspecific Hybridization of Meiotic Parthenogenetic Meloidogyne chitwoodi and M. fallax

1997 ◽  
Vol 87 (10) ◽  
pp. 1061-1066 ◽  
Author(s):  
J. G. van der Beek ◽  
G. Karssen
Keyword(s):  
Malate Dehydrogenase ◽  
Interspecific Hybridization ◽  
Genetic Material ◽  
Conclusive Evidence ◽  
Species Differentiation ◽  
Mating Experiment ◽  
Meloidogyne Chitwoodi ◽  
Isozyme Electrophoresis ◽  
Parental Type ◽  
Clear Differentiation

Hybridization between two meiotic parthenogenetic species of root-knot nematodes, Meloidogyne chitwoodi and M. fallax, was investigated in two different crossing experiments on tomato plants grown in sand. The first experiment was a controlled cross between the two species. The second experiment was a bulk mating in a 1:1 mixture of two isolates. The haploid chromosome number of the parental isolates was n = 18. Successful interspecific hybridization was obtained, and the resulting hybrids produced egg masses. In eggs, cell division was observed, but most of them were without clear differentiation and consequently were sterile. Hatched F2 juveniles were small in number, not viable, and showed morphological distortions. In the progeny of the isolate mixture of the bulk mating experiment, parental-type females of the two isolates were present in equal numbers, and 10% of all females were nonviable hybrids. Similar ratios of parental-type and hybrid females were detected in roots of test plants grown in soil from a field sample that contained a mixture of M. chitwoodi and M. fallax populations. In the controlled cross experiment, isozyme electrophoresis of malate dehydrogenase was applied to distinguish the two species and their hybrids. In the bulk mating experiment, malate dehydrogenase, esterase, and glucose 6-phosphate dehydrogenase were used as markers, two by two simultaneously on the same individual females, providing conclusive evidence for the occurrence of hybrids. This is the first report on interspecific hybridization in Meloidogyne. The possible role of interspecific hybridization in species differentiation and interspecific exchange of genetic material within Meloidogyne is discussed.

scholarly journals Genome assembly, structural variants, and genetic differentiation between Lake Whitefish young species pairs (Coregonus sp.) with long and short reads

2022 ◽  
Author(s):  
Claire M&eacuterot ◽  
Kristina S R Stenl&oslashkk ◽  
Clare Venney ◽  
Martin Laporte ◽  
Michel Moser ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Genetic Architecture ◽  
Large Fraction ◽  
Sympatric Species ◽  
Secondary Contact ◽  
Species Differentiation ◽  
Lake Whitefish ◽  
Structural Variants ◽  
Species Pairs ◽  
Long Read

The parallel evolution of nascent pairs of ecologically differentiated species offers an opportunity to get a better glimpse at the genetic architecture of speciation. Of particular interest is our recent ability to consider a wider range of genomic variants, not only single-nucleotide polymorphisms (SNPs), thanks to long-read sequencing technology. We can now identify structural variants (SVs) like insertions, deletions, and other structural rearrangements, allowing further insights into the genetic architecture of speciation and how different variants are involved in species differentiation. Here, we investigated genomic patterns of differentiation between sympatric species pairs (Dwarf and Normal) belonging to the Lake Whitefish (Coregonus clupeaformis) species complex. We assembled the first reference genomes for both Dwarf and Normal Lake Whitefish, annotated the transposable elements, and analysed the genome in the light of related coregonid species. Next, we used a combination of long-read and short-read sequencing to characterize SVs and genotype them at population-scale using genome-graph approaches, showing that SVs cover five times more of the genome than SNPs. We then integrated both SNPs and SVs to investigate the genetic architecture of species differentiation in two different lakes and highlighted an excess of shared outliers of differentiation. In particular, a large fraction of SVs differentiating the two species was driven by transposable elements (TEs), suggesting that TE accumulation during a period of allopatry predating secondary contact may have been a key process in the speciation of the Dwarf and Normal Whitefish. Altogether, our results suggest that SVs play an important role in speciation and that by combining second and third generation sequencing we now have the ability to integrate SVs into speciation genomics.

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