Genetic Structure of Anadromous Cutthroat Trout (Salmo clarki clarki) Populations in the Puget Sound Area: Evidence for Restricted Gene Flow

1987 ◽  
Vol 44 (3) ◽  
pp. 573-582 ◽  
Author(s):  
Donald E. Campton ◽  
Fred M. Utter
Keyword(s):  
Gene Flow ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
Puget Sound ◽  
Cutthroat Trout ◽  
Restricted Gene Flow ◽  
Pleistocene Glaciation ◽  
Expected Heterozygosity ◽  
Coastal Cutthroat Trout ◽  
Salmo Clarki

Genetic relationships among anadromous populations of coastal cutthroat trout (Salmo clarki clarki) in the Puget Sound area (United States) were investigated by electrophoretic methods between successive year classes within streams (populations), among streams within drainages, between drainages within each of two regions separated by Puget Sound, and between the two regions. Average allele frequencies for fish from the two regions differed by approximately 0.10 at several polymorphic loci, suggesting that gene flow between the two regions is restricted. Despite this divergence, the sampled populations were all very similar genetically (Nei's I > 0.97), possibly reflecting a common ancestral invasion following Pleistocene glaciation. The total gene diversity (expected heterozygosity) was 0.101 and was partitioned as follows: between regions, 1.24%; between drainages, 1.01%; among streams, 2.41%; between year classes, 1.17%; within individual year class samples, 94.2%. In addition, stream effects were significant in 7 of 12 intralocus ANOVA comparisons, suggesting that populations were structured genetically at this level of subdivision. This latter result may be reflecting the homing instinct of spawning adults.

Genetic structure and proposed conservation strategy for natural populations of Calycanthus chinensis Cheng et S.Y. Chang (Calycanthaceae)

2008 ◽  
Vol 88 (1) ◽  
pp. 179-186 ◽  
Author(s):  
Chu-Chuan Fan ◽  
Nicola Pecchioni ◽  
Long-Qing Chen
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Population Level ◽  
Conservation Strategy ◽  
Information Index

Calycanthus chinensis Cheng et S.Y. Chang, a tertiary relic species in China, is a shade-loving and deciduous bush withan elegant shape and beautiful flower of high ornamental value. It was widely planted in gardens and miniature scapes in China.The objective of this study was to characterize the genetic variation and structure in the three extant populations of the species, in order to provide useful information for a future conservation strategy. Twenty-two of 120 RAPD primers were selected and a total of 257 stable and clear DNA fragments were scored. Calycanthus chinensis showed a lower level of genetic diversity. At the population level, the percentage of polymorphic loci, Nei's gene diversity and Shannon’s information index were 40.9%, 0.1641 and 0.2386, respectively; while at the species level, the corresponding values were 59.1%, 0.2097 and 0.3123, respectively. The estimates of genetic differentiation based on Shannon’s information index (0.2360), Nei’s gene diversity (0.2175) and AMOVA (24.94%) were very similar, and significantly higher than the average genetic differentiation reported in outcrossed spermatophyte. So it suggested high genetic differentiation emerged among populations of C. chinensis. Genetic relationships among populations were assessed by Nei’s standard genetic distance, which suggested that the Tiantai population was genetically distinct from the other two populations. Moreover, the genetic distance was significantly correlated with geographical distance among populations (r = 0.997, t > t0.05). The gene flow (Nm) was 0.8994, indicating that gene exchange among populations was restricted. A conservation strategy was proposed based on the low gene flow and habitat deterioration, which are contributing to the endangered status of this species. Key words: Genetic diversity, endangered plant, population genetics, RAPD

Karyotypic and Evolutionary Relationships of the Yellowstone (Salmo clarki bouvieri) and West-Slope (S. c. lewisi) Cutthroat Trout

1979 ◽  
Vol 36 (6) ◽  
pp. 630-635 ◽  
Author(s):  
Eric J. Loudenslager ◽  
Gary H. Thorgaard
Keyword(s):  
Key Words ◽  
Great Basin ◽  
Cutthroat Trout ◽  
Rocky Mountain ◽  
Mountain Region ◽  
Evolutionary Relationships ◽  
Rocky Mountain Region ◽  
Coastal Cutthroat Trout ◽  
Yellowstone Cutthroat Trout ◽  
Salmo Clarki

Yellowstone cutthroat trout (Salmo clarki bouvieri) have 64 chromosomes, without any subtelocentric chromosomes, while west-slope cutthroat trout (S. c. lewisi) have 66 chromosomes, including 12 subtelocentrics. Both subspecies have 104 chromosome arms. Chromosomal similarities are apparent between the Yellowstone cutthroat and Great Basin cutthroat subspecies, and between west-slope cutthroat trout and coastal cutthroat trout. These results demonstrate that at least two distinct evolutionary lines of cutthroat trout are present in the northern Rocky Mountain region. Key words: Salmo clarki, karyotypes, Yellowstone cutthroat trout, west-slope cutthroat trout, evolutionary relationships

The Relation between Scale Diameter and Body Length of Kamloops Trout, Salmo gairdneri kamloops

1955 ◽  
Vol 12 (5) ◽  
pp. 742-753 ◽  
Author(s):  
S. B. Smith
Keyword(s):  
Fork Length ◽  
Cutthroat Trout ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Double Logarithmic Plot ◽  
Relative Growth ◽  
Coastal Cutthroat Trout ◽  
Constant Slope ◽  
Salmo Clarki ◽  
Simple Proportion

The scale/body relationship for Kamloops trout is very close to direct proportion for fish larger than 4.5 cm. fork length. The resultant plot on a double logarithmic grid is linear with a slope not significantly different from 1.00 (45°). Calculations of lengths of trout from scales at ages previous to that of capture can be made on the basis of simple proportion in two ways, (1) by use of a constant slope (45°) on a double logarithmic plot, or (2) by use of a constant zero-zero intercept on an arithmetic plot.Growth of the scales of the young is characterized by relatively rapid increase from time of scale formation, 3.5 cm. fork length up to 4.5 cm. At about 4.5 cm. fork length there is a sharp break (inflection) in the relative growth curve toward isometric growth of scales and body. Reliable estimates of the length of trout may be obtained from scales alone, using the diameter of the first circulus of the scale, the slopes and inflection of the relative scale/body plot and total diameter of the scale at time of capture.Marked Kamloops trout of known size were released in 1953. Subsequent recaptures both in 1953 and 1954 substantiated the accuracy of the method of estimating lengths of trout at ages previous to that of capture.Observations on the steelhead trout, Salmo gairdneri gairdneri, and on the coastal cutthroat trout, Salmo clarki clarki, suggest that an isometric scale/body relationship may exist among those species also.

Natural Hybridization between Steelhead Trout (Salmo gairdneri) and Coastal Cutthroat Trout (Salmo clarki clarki) in Two Puget Sound Streams

1985 ◽  
Vol 42 (1) ◽  
pp. 110-119 ◽  
Author(s):  
Donald E. Campton ◽  
Fred M. Utter
Keyword(s):  
Management Practices ◽  
Random Mating ◽  
Puget Sound ◽  
Cutthroat Trout ◽  
Natural Hybridization ◽  
Salmo Gairdneri ◽  
Hybrid Index ◽  
Steelhead Trout ◽  
Mixed Ancestry ◽  
Coastal Cutthroat Trout

A genetic investigation of anadromous trout populations in the Puget Sound area revealed numerous juvenile individuals from two streams with electrophoretic phenotypes consistent with those expected for hybrid descendents of steelhead trout (Salmo gairdneri) and coastal cutthroat trout (S. clarki clarki). The likelihood of hybridization was evaluated with a hybrid index measuring the relative probability that the combined genotype for a particular fish at several diagnostic loci could have arisen by random mating within each of the two Salmo species. The distribution of hybrid index scores among fish from the two creeks clearly demonstrated the genetic distinctness of the two species and the intermediate genotypic composition of the unknown fish. We concluded that these electrophoretically intermediate fish were natural steelhead–cutthroat hybrids based on their restricted occurrence at specific sample sites in only 2 of 23 streams surveyed, the linear distributions of juveniles from the two parental species within each stream, and the distribution of hybrid index values for a hatchery population of known mixed ancestry. Further, from estimates of gametic disequilibria and the absence of a consistent excess of heterozygotes we suggest that backcrossing may have occurred. The existence of these natural hybrids raises many questions concerning the biological bases for maintaining species integrities in regions of sympatry and indicates the need to fully understand the biological consequences of present and future management practices.

scholarly journals The Genetic Structure of Australian Populations of Mycosphaerella musicola Suggests Restricted Gene Flow at the Continental Scale

2005 ◽  
Vol 95 (5) ◽  
pp. 489-498 ◽  
Author(s):  
H. L. Hayden ◽  
J. Carlier ◽  
E. A. B. Aitken
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Gene Diversity ◽  
Infected Plant ◽  
Single Copy ◽  
Restricted Gene Flow ◽  
Genotype Distribution ◽  
Continental Scale ◽  
Mycosphaerella Musicola ◽  
Production Areas

Mycosphaerella musicola causes Sigatoka disease of banana and is endemic to Australia. The population genetic structure of M. musicola in Australia was examined by applying single-copy restriction fragment length polymorphism probes to hierarchically sampled populations collected along the Australian east coast. The 363 isolates studied were from 16 plantations at 12 sites in four different regions, and comprised 11 populations. These populations displayed moderate levels of gene diversity (H = 0.142 to 0.369) and similar levels of genotypic richness and evenness. Populations were dominated by unique genotypes, but isolates sharing the same genotype (putative clones) were detected. Genotype distribution was highly localized within each population, and the majority of putative clones were detected for isolates sampled from different sporodochia in the same lesion or different lesions on a plant. Multilocus gametic disequilibrium tests provided further evidence of a degree of clonality within the populations at the plant scale. A complex pattern of population differentiation was detected for M. musicola in Australia. Populations sampled from plantations outside the two major production areas were genetically very different to all other populations. Differentiation was much lower between populations of the two major production areas, despite their geographic separation of over 1,000 km. These results suggest low gene flow at the continental scale due to limited spore dispersal and the movement of infected plant material.

Cutthroat Trout: Evolutionary Biology and Taxonomy

2018 ◽  
Author(s):  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Rainbow Trout ◽  
Evolutionary Biology ◽  
Isolation By Distance ◽  
Cutthroat Trout ◽  
Population Connectivity ◽  
Oncorhynchus Clarkii ◽  
Habitat Alterations ◽  
Coastal Cutthroat Trout

<em>Abstract</em>.—We examined patterns of dispersal and colonization after Cordilleran glaciations, population connectivity, levels of genetic diversity, and potential impacts of anthropogenic changes to Coastal Cutthroat Trout <em>Oncorhynchus clarkii clarkii</em>. Populations were mostly small with restricted dispersals but exchanged one to two migrants per generation on average. Genetic differences among local populations of Coastal Cutthroat Trout accounted for approximately three-fourths of the total genetic variation among groups, with differences among different geographical groups accounting for the rest. Because of this, hierarchical geographical population structure was difficult to detect except at small geographical scales that reflected local dispersal and gene flow or at broad geographical scales that reflected divergence associated with long-term isolation during Cordilleran glacial advances. Evolutionary processes such as gene flow and genetic drift reflected in isolation by distance occurred at distances up to 600–700 km but mostly lesser distances, whereas divergence associated with Pleistocene glaciation occurred at 1,900 km or greater. Glacial refugia existed south of the Salish Sea along the Washington, Oregon, and California coasts; in the Haida Gwaii or Alexander Archipelago; and possibly near the central coast of British Columbia near Bella Coola. Throughout the range, hybridization with Rainbow Trout <em>O. mykiss </em>or steelhead (anadromous Rainbow Trout) appears to occur naturally at low levels, but releases of hatchery-produced <em>O. mykiss </em>can lead to higher levels of hybridization and rarely hybrid swarms. Degraded habitat may contribute to hybridization, but most anthropogenic habitat alterations reduce habitat quantity and quality and disrupt opportunities for dispersal, contributing to declines in abundance, population connectivity, and genetic diversity.

Activity Localization in Coastal Cutthroat Trout (Salmo clarki clarki) in a Small Bog Lake

1974 ◽  
Vol 31 (7) ◽  
pp. 1246-1249 ◽  
Author(s):  
B. G. Shepherd
Keyword(s):  
Cutthroat Trout ◽  
Focal Points ◽  
Mark Recapture ◽  
Coastal Cutthroat Trout ◽  
Ultrasonic Tracking ◽  
Salmo Clarki

Skindiving observations, ultrasonic tracking, and mark–recapture techniques indicated that coastal cutthroat trout (Salmo clarki clarki) in a small coastal bog lake have, but do not defend, fixed focal points of activity.

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