Isozyme variation and its environmental correlates in Elymus glaucus from the California Floristic Province

2001 ◽  
Vol 79 (2) ◽  
pp. 139-153 ◽  
Author(s):  
Barbara L Wilson ◽  
Jay Kitzmiller ◽  
Wayne Rolle ◽  
Valerie D Hipkins
Keyword(s):  
Genetic Variation ◽  
San Francisco ◽  
Sierra Nevada ◽  
Geographic Distance ◽  
Geographic Location ◽  
Taxonomic Status ◽  
Genetic Distances ◽  
Leaf Pubescence ◽  
Seed Transfer ◽  
Elymus Glaucus

Genetic variation in the self-fertile, allotetraploid grass Elymus glaucus Buckley was assessed using isozymes in 133 populations from southwestern Oregon and from the San Francisco Bay area and central Sierra Nevada mountains in California. Elymus glaucus was highly (98.5%) homozygous but also highly variable; 77% of loci were polymorphic, and the mean number of alleles per locus was 2.96. Populations were highly differentiated, with 40% of variation among populations. Geographic and genetic distances among populations were not correlated, except that populations collected within 5 km were generally more similar than average. Genetic distance among populations could not be predicted from geographic distance, geographic location, foliage pubescence, serpentine substrate, or habitat moisture. However, two genetic clusters, associated with elevation, did emerge. The taxonomic status of Elymus glaucus ssp. jepsonii (Burtt Davy) Gould, based on leaf pubescence, was not supported.Key words: Elymus glaucus, isozyme, genetic variation, Poaceae, polyploid, seed transfer.

Metacercarial polymorphism and genetic variation of Paragonimus heterotremus (Digenea: Paragonimidae), and a re-appraisal of the taxonomic status of Paragonimus pseudoheterotremus

2013 ◽  
Vol 89 (2) ◽  
pp. 182-188 ◽  
Author(s):  
P.N. Doanh ◽  
U. Thaenkham ◽  
P.T. An ◽  
H.V. Hien ◽  
Y. Horii ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Taxonomic Status ◽  
Haplotype Network ◽  
Genetic Distances ◽  
Maximum Diameter ◽  
Molecular Characteristics ◽  
Extensive Collection ◽  
Different Populations ◽  
A New Species ◽  
India And China

AbstractParagonimus heterotremus, which is an important pathogen for human paragonimiasis in Asia, is recognized as having the smallest metacercariae (maximum diameter < 300 μm) of any previously reported Paragonimus species. Recently, P. pseudoheterotremus has been described from Thailand as a new species having metacercariae (about 200 μm) slightly smaller than those of Thai P. heterotremus. In fact, the small size of P. pseudoheterotremus metacercariae is compatible with those of P. heterotremus from India and China. In this study in Vietnam, we found variably sized small metacercariae which are expected to consist of both P. heterotremus and P. pseudoheterotremus. Contrary to expectation, the adult flukes obtained by separate infection of experimental cats with different sized metacercariae were all identified as P. heterotremus, using both morphological and molecular characteristics. The molecular analyses of an extensive collection of P. heterotremus/P. pseudoheterotremus isolates from Asian countries also indicated that genetic distances between different populations of P. heterotremus are even larger than that between P. pseudoheterotremus and P. heterotremus. The haplotype network showed that all P. heterotremus and P. pseudoheterotremus isolates formed a P. heterotremus complex consisting of three groups with strong geographical origins. In addition, the Indian P. heterotremus group is the root of the other P. heterotremus and P. pseudoheterotremus populations. Based on the observed metacercarial polymorphisms and genetic variation in P. heterotremus,P. pseudoheterotremus should be considered a geographically isolated population of the P. heterotremus complex.

Landscape patterns of phenotypic variation and population structuring in a selfing grass, Elymus glaucus (blue wildrye)

2004 ◽  
Vol 82 (12) ◽  
pp. 1776-1789 ◽  
Author(s):  
Vicky J Erickson ◽  
Nancy L Mandel ◽  
Frank C Sorensen
Keyword(s):  
Genetic Variation ◽  
Principal Component ◽  
Common Garden ◽  
Primary Objective ◽  
Landscape Patterns ◽  
Clinal Variation ◽  
Phenotypic Variance ◽  
Seed Transfer ◽  
Wide Range ◽  
Elymus Glaucus

Source-related phenotypic variance was investigated in a common garden study of populations of Elymus glaucus Buckley (blue wildrye) from the Blue Mountain Ecological Province of northeastern Oregon and adjoining Washington. The primary objective of this study was to assess geographic patterns of potentially adaptive differentiation in this self-fertile allotetraploid grass, and use this information to develop a framework for guiding seed movement and preserving adaptive patterns of genetic variation in ongoing restoration work. Progeny of 188 families were grown for 3 years under two moisture treatments and measured for a wide range of traits involving growth, morphology, fecundity, and phenology. Variation among seed sources was analyzed in relation to physiographic and climatic trends, and to various spatial stratifications such as ecoregions, watersheds, edaphic classifications, etc. Principal component (PC) analysis extracted four primary PCs that together accounted for 67% of the variance in measured traits. Regression and cluster analyses revealed predominantly ecotypic or stepped-clinal distribution of genetic variation. Three distinct geographic groups of locations accounted for over 84% of the variation in PC-1 and PC-2 scores; group differences were best described by longitude and ecoregion. Clinal variation in PC-3 and PC-4 scores was present in the largest geographic group. Four geographic subdivisions were proposed for delimiting E. glaucus seed transfer in the Blue Mountains.Key words: Elymus glaucus, morphological variation, local adaptation, seed transfer, seed zones, polyploid.

Allozyme variation in sugar maple at the northern limit of its range in Ontario, Canada

1989 ◽  
Vol 19 (4) ◽  
pp. 509-514 ◽  
Author(s):  
D. J. Perry ◽  
P. Knowles
Keyword(s):  
Genetic Variation ◽  
Sugar Maple ◽  
Geographic Distance ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Canonical Discriminant Analysis ◽  
Ancestral Population ◽  
Allelic Heterogeneity ◽  
Northern Limit ◽  
Northern Ontario

Genetic variation in five populations of sugar maple (Acersaccharum Marsh.) from northern Ontario was analysed electrophoretically for seven enzymes encoded by 11 structural loci. On average, populations were polymorphic at 38.2% of the loci, with 1.95 alleles per locus. Although FST estimates indicated that only 3% of the genetic variability was among populations, there was significant allelic heterogeneity at all polymorphic loci. Canonical discriminant analysis also indicated substantial differentiation among populations. Genetic distances between populations ranged from 0.0009 to 0.0125, but no relationship with geographic distance was apparent. It is suggested that pockets of sugar maple found at the northern limit of its range in Ontario may be relics of a more continuous ancestral population which may have existed during the hypsithermal interval.

Transportation and the Environment

2017 ◽  
Vol 94 (3) ◽  
pp. 37-61
Author(s):  
Douglas R. Littlefield
Keyword(s):  
Nineteenth Century ◽  
San Francisco ◽  
Sierra Nevada ◽  
Mississippi River ◽  
San Joaquin Valley ◽  
Eastern United States ◽  
Major Health ◽  
San Joaquin River ◽  
Natural Wetlands ◽  
Prevailing View

Some histories of California describe nineteenth-century efforts to reclaim the extensive swamplands and shallow lakes in the southern part of California's San Joaquin Valley – then the largest natural wetlands habitat west of the Mississippi River – as a herculean venture to tame a boggy wilderness and turn the region into an agricultural paradise. Yet an 1850s proposition for draining those marshes and lakes primarily was a scheme to improve the state's transportation. Swampland reclamation was a secondary goal. Transport around the time of statehood in 1850 was severely lacking in California. Only a handful of steamboats plied a few of the state's larger rivers, and compared to the eastern United States, roads and railroads were nearly non-existent. Few of these modes of transportation reached into the isolated San Joaquin Valley. As a result, in 1857 the California legislature granted an exclusive franchise to the Tulare Canal and Land Company (sometimes known as the Montgomery franchise, after two of the firm's founders). The company's purpose was to connect navigable canals from the southern San Joaquin Valley to the San Joaquin River, which entered from the Sierra Nevada about half way up the valley. That stream, in turn, joined with San Francisco Bay, and thus the canals would open the entire San Joaquin Valley to world-wide commerce. In exchange for building the canals, the Montgomery franchise could collect tolls for twenty years and sell half the drained swamplands (the other half was to be sold by the state). Land sales were contingent upon the Montgomery franchise reclaiming the marshes. Wetlands in the mid-nineteenth century were not viewed as they are today as fragile wildlife habitats but instead as impediments to advancing American ideals and homesteads across the continent. Moreover, marshy areas were seen as major health menaces, with the prevailing view being that swampy regions’ air carried infectious diseases.

scholarly journals Genomic variation in the American pika: signatures of geographic isolation and implications for conservation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kelly B. Klingler ◽  
Joshua P. Jahner ◽  
Thomas L. Parchman ◽  
Chris Ray ◽  
Mary M. Peacock
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Sierra Nevada ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Thermal Sensitivity ◽  
Genomic Variation ◽  
Genome Wide ◽  
A Genome ◽  
American Pika

Abstract Background Distributional responses by alpine taxa to repeated, glacial-interglacial cycles throughout the last two million years have significantly influenced the spatial genetic structure of populations. These effects have been exacerbated for the American pika (Ochotona princeps), a small alpine lagomorph constrained by thermal sensitivity and a limited dispersal capacity. As a species of conservation concern, long-term lack of gene flow has important consequences for landscape genetic structure and levels of diversity within populations. Here, we use reduced representation sequencing (ddRADseq) to provide a genome-wide perspective on patterns of genetic variation across pika populations representing distinct subspecies. To investigate how landscape and environmental features shape genetic variation, we collected genetic samples from distinct geographic regions as well as across finer spatial scales in two geographically proximate mountain ranges of eastern Nevada. Results Our genome-wide analyses corroborate range-wide, mitochondrial subspecific designations and reveal pronounced fine-scale population structure between the Ruby Mountains and East Humboldt Range of eastern Nevada. Populations in Nevada were characterized by low genetic diversity (π = 0.0006–0.0009; θW = 0.0005–0.0007) relative to populations in California (π = 0.0014–0.0019; θW = 0.0011–0.0017) and the Rocky Mountains (π = 0.0025–0.0027; θW = 0.0021–0.0024), indicating substantial genetic drift in these isolated populations. Tajima’s D was positive for all sites (D = 0.240–0.811), consistent with recent contraction in population sizes range-wide. Conclusions Substantial influences of geography, elevation and climate variables on genetic differentiation were also detected and may interact with the regional effects of anthropogenic climate change to force the loss of unique genetic lineages through continued population extirpations in the Great Basin and Sierra Nevada.

Significant genetic differences among Heterodera schachtii populations within and among sugar beet production areas

Nematology ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 165-177 ◽  
Author(s):  
Rasha Haj Nuaima ◽  
Johannes Roeb ◽  
Johannes Hallmann ◽  
Matthias Daub ◽  
Holger Heuer
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Spatial Scales ◽  
Geographic Distance ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Neutral Genetic Variation ◽  
Production Areas

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.

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 Genetic Variation Among Colletotrichum graminicola Isolates from Four Hosts Using Isozyme Analysis

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 402-406 ◽  
Author(s):  
B. J. Horvath ◽  
J. M. Vargas
Keyword(s):  
Genetic Variation ◽  
Genetic Distance ◽  
Geographic Origin ◽  
Creeping Bentgrass ◽  
Genetic Distances ◽  
Colletotrichum Graminicola ◽  
Annual Bluegrass ◽  
Close Relationship ◽  
Host Origin ◽  
Serious Disease

Anthracnose basal rot (ABR) is a serious disease of turfgrasses that is caused by the pathogen Colletotrichum graminicola. The relationships of isolates causing ABR on turfgrasses to those causing disease on important crop hosts (maize, sorghum) remain unresolved. Genetic variation among isolates from annual bluegrass, creeping bentgrass, maize, and sorghum was evaluated based on host origin and geographic origin. Isozymes were used to estimate the genetic variation of the isolates. Five enzyme systems comprising 16 alleles from 5 loci were used. Allele frequencies, genetic distance, and linkage disequilibrium values were calculated for isolates based on both host and geographic origin. Isolates from creeping bentgrass and annual bluegrass were the most closely related based on Nei's genetic distance, while isolates from maize and sorghum were the most distantly related, consistent with their known species-level relationship. Isolates from annual bluegrass and creeping bentgrass had different genetic distances to isolates from both maize and sorghum. Annual bluegrass isolates from different geographic regions had the smallest genetic distance values observed in this study, indicating a very close relationship regardless of geographic origin. Based on these data, it appears that host origin, not geographic origin, plays a more important role in the genetic diversity of these fungi.

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.

Detection of genetic diversity in rough fescue (Festuca campestris Rydb) populations of southern Alberta and British Columbia, Canada, using RAPD markers

2008 ◽  
Vol 88 (2) ◽  
pp. 307-312
Author(s):  
Zhao Mengli ◽  
Han Bing ◽  
Walter D Willms
Keyword(s):  
Genetic Diversity ◽  
British Columbia ◽  
Genetic Distance ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Distance ◽  
Genetic Distances ◽  
Gene Frequencies ◽  
Southern Alberta ◽  
Potential Adaptation ◽  
Rough Fescue

Mountain rough fescue (Festuca campestris Rydb.) is a tufted native grass in southern Alberta and British Columbia, Canada, and has attracted interest for use in reclamation. However, its seed is often available from only a few localized sources and may not be adapted for areas removed from the collection site. We conducted a study to determine the genetic variability among rough fescue populations to assess its potential adaptation. Thirty plants were collected from each of six populations and analyzed using Random Amplified Polymorphic DNA (RAPD). One population (Kamloops, BC) was separated by several mountain ranges from the five easterly Alberta populations.The Kamloops population was also separated from the Alberta populations by genetic distance in two clusters. Of the total genetic variation present in the data, 21% was found among populations while the remaining (79%) was found within populations. Nei’s genetic distances among populations were related to their geographical distances. Genetic differences among populations appeared to be caused primarily by differences in gene frequencies rather than rare genes. Also, genetic diversity appeared to increase from west to east suggesting that the more easterly populations had greater adaptation potential. We speculate that the more easterly populations are less likely to share genes since the prevailing winds are from the west. Germplasm from the more easterly populations may be used with suitable precautions within Alberta and possibly around Kamloops. Key words: Genetic distance, geographic distance, reclamation, potential adaptation

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