scholarly journals Limited effects of source population identity and number on seagrass transplant performance

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2972 ◽  
Author(s):  
Alyssa B. Novak ◽  
Holly K. Plaisted ◽  
Cynthia G. Hays ◽  
Randall A. Hughes
Keyword(s):  
Genetic Variation ◽  
Zostera Marina ◽  
Population Level ◽  
Shoot Density ◽  
Population Diversity ◽  
Multiple Source ◽  
Source Population ◽  
Post Transplantation ◽  
Home Site ◽  
Source Populations

Global declines in coastal foundation species highlight the importance of effective restoration. In this study, we examined the effects of source population identity and diversity (one vs. three sources per plot) on seagrass (Zostera marina) transplant success. The field experiment was replicated at two locations in Massachusetts with adjacent naturalZostera marinabeds to test for local adaptation and source diversity effects on shoot density. We also collected morphological and genetic data to characterize variation within and among source populations, and evaluate whether they were related to performance. Transplants grew and expanded until six months post-transplantation, but then steadily declined at both sites. Prior to declines, we observed variation in performance among source populations at one site that was related to morphological traits: the populations with the longest leaves had the highest shoot densities, whereas the population with the shortest leaves performed the worst at six months post-transplantation. In addition, multiple source plots at this same transplant site consistently had similar or higher shoot densities than single source plots, and shoots from weak-performing populations showed improved performance in multiple source plots. We found no evidence for home site advantage or benefits of population-level genetic variation in early transplant performance at either site. Our results show limited effects of source population on early transplant performance and suggest that factors (e.g., morphology) other than home site advantage and population genetic variation serve a role. Based on our overall findings that transplant success varied among source populations and that population diversity at the plot level had positive but limited effects on individual and plot performance, we support planting shoots from multiple source sites in combination to enhance transplant success, particularly in the absence of detailed information on individual source characteristics.

scholarly journals On the heterozygosity of an admixed population

2019 ◽  
Author(s):  
Simina M. Boca ◽  
Lucy Huang ◽  
Noah A. Rosenberg
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Genetic Variants ◽  
Simulated Data ◽  
Source Population ◽  
Admixed Population ◽  
Source Populations ◽  
Special Case

A population is termed admixed if its members possess recent ancestry from two or more separate sources. As a result of the fusion of source populations with different genetic variants, admixed populations can exhibit high levels of genetic variation, reflecting contributions of their multiple ancestral groups. For a model of an admixed population derived from K source groups, we obtain a relationship between its level of genetic variation, as measured by heterozygosity, and its proportions of admixture from the various source populations. We show that the heterozygosity of the admixed population is at least as great as that of the least heterozygous source population, and that it potentially exceeds the heterozygosities of all of the source populations. The admixture proportions that maximize the heterozygosity possible for an admixed population formed from a specified set of source populations are also obtained under specific conditions. We examine the special case of K = 2 source populations in detail, characterizing the maximal admixture in terms of the heterozygosities of the two source populations and the value of FST between them. In this case, the heterozygosity of the admixed population exceeds the maximal heterozygosity of the source groups if the divergence between them, measured by FST, is large enough, namely above a certain bound that is a function of the heterozygosities of the source groups. We present applications to simulated data as well as to data from human admixture scenarios, providing results useful for interpreting the properties of genetic variability in admixed populations.

The Effects of Predator Evolution and Genetic Variation on Predator–Prey Population-Level Dynamics

2017 ◽  
Vol 79 (7) ◽  
pp. 1510-1538 ◽  
Author(s):  
Michael H. Cortez ◽  
Swati Patel
Keyword(s):  
Genetic Variation ◽  
Population Level ◽  
Prey Population ◽  
Predator Prey

scholarly journals Simulation-Based Evaluation of Three Methods for Local Ancestry Deconvolution of Non-model Crop Species Genomes

2019 ◽  
Vol 10 (2) ◽  
pp. 569-579
Author(s):  
Aurélien Cottin ◽  
Benjamin Penaud ◽  
Jean-Christophe Glaszmann ◽  
Nabila Yahiaoui ◽  
Mathieu Gautier
Keyword(s):  
R Package ◽  
Source Population ◽  
Crop Species ◽  
Data Set ◽  
Reproduction Mode ◽  
Local Ancestry ◽  
Ancestry Inference ◽  
Source Populations ◽  
Inference Methods ◽  
Local Ancestry Inference

Hybridizations between species and subspecies represented major steps in the history of many crop species. Such events generally lead to genomes with mosaic patterns of chromosomal segments of various origins that may be assessed by local ancestry inference methods. However, these methods have mainly been developed in the context of human population genetics with implicit assumptions that may not always fit plant models. The purpose of this study was to evaluate the suitability of three state-of-the-art inference methods (SABER, ELAI and WINPOP) for local ancestry inference under scenarios that can be encountered in plant species. For this, we developed an R package to simulate genotyping data under such scenarios. The tested inference methods performed similarly well as far as representatives of source populations were available. As expected, the higher the level of differentiation between ancestral source populations and the lower the number of generations since admixture, the more accurate were the results. Interestingly, the accuracy of the methods was only marginally affected by i) the number of ancestries (up to six tested); ii) the sample design (i.e., unbalanced representation of source populations); and iii) the reproduction mode (e.g., selfing, vegetative propagation). If a source population was not represented in the data set, no bias was observed in inference accuracy for regions originating from represented sources and regions from the missing source were assigned differently depending on the methods. Overall, the selected ancestry inference methods may be used for crop plant analysis if all ancestral sources are known.

scholarly journals High differentiation in functional traits but similar phenotypic plasticity in populations of a soil specialist along a climatic gradient

2020 ◽  
Vol 125 (6) ◽  
pp. 969-980 ◽  
Author(s):  
Silvia Matesanz ◽  
Marina Ramos-Muñoz ◽  
Mario Blanco-Sánchez ◽  
Adrián Escudero
Keyword(s):  
Genetic Variation ◽  
Phenotypic Plasticity ◽  
Functional Traits ◽  
Common Garden ◽  
Population Level ◽  
General Purpose ◽  
Climatic Conditions ◽  
Environment Interaction ◽  
Moisture Variation ◽  
Neutral Genetic Variation

Abstract Background and Aims Plants experiencing contrasting environmental conditions may accommodate such heterogeneity by expressing phenotypic plasticity, evolving local adaptation or a combination of both. We investigated patterns of genetic differentiation and plasticity in response to drought in populations of the gypsum specialist Lepidium subulatum. Methods We created an outdoor common garden with rain exclusion structures using 60 maternal progenies from four distinct populations that substantially differ in climatic conditions. We characterized fitness, life history and functional plasticity in response to two contrasting treatments that realistically reflect soil moisture variation in gypsum habitats. We also assessed neutral genetic variation and population structure using microsatellite markers. Key Results In response to water stress, plants from all populations flowered earlier, increased allocation to root tissues and advanced leaf senescence, consistent with a drought escape strategy. Remarkably, these probably adaptive responses were common to all populations, as shown by the lack of population × environment interaction for almost all functional traits. This generally common pattern of response was consistent with substantial neutral genetic variation and large differences in population trait means. However, such population-level trait variation was not related to climatic conditions at the sites of origin. Conclusions Our results show that, rather than ecotypes specialized to local climatic conditions, these populations are composed of highly plastic, general-purpose genotypes in relation to climatic heterogeneity. The strikingly similar patterns of plasticity among populations, despite substantial site of origin differences in climate, suggest past selection on a common norm of reaction due to similarly high levels of variation within sites. It is thus likely that plasticity will have a prevalent role in the response of this soil specialist to further environmental change.

Genetic structure of Gahnia radula (Cyperaceae), a key sedge for revegetation

2017 ◽  
Vol 65 (2) ◽  
pp. 128
Author(s):  
Alex Arnold ◽  
Andrea Kodym ◽  
Nancy M. Endersby-Harshman ◽  
John Delpratt ◽  
Ary A. Hoffmann
Keyword(s):  
Genetic Variation ◽  
Adaptive Potential ◽  
Genetic Studies ◽  
Potential Source ◽  
Landscape Processes ◽  
Disturbed Areas ◽  
Eastern Australia ◽  
Genetic Patterns ◽  
Source Populations ◽  
High Level

Genetic studies can help guide effective ecological restoration by identifying potential source populations that contain the genetic variation necessary for adaptive potential, based on past landscape processes. Here we investigate genetic patterns in Gahnia radula (R.Br.) Benth., a sedge from south-eastern Australia that has potential for revegetation of disturbed areas. We developed microsatellite markers for this species and used them to show that it propagates mostly in a clonal manner. Levels of genetic variability differed between populations and the spatial scale of this variability within these populations is identified. A population used in recent restoration efforts and which sets seed has a particularly high level of variability. Recommendations are developed for sourcing material when using this sedge for revegetation.

scholarly journals Populations Are Differentiated in Biological Rhythms without Explicit Elevational Clines in the Plant Mimulus laciniatus

2020 ◽  
Vol 35 (5) ◽  
pp. 452-464
Author(s):  
Päivi H. Leinonen ◽  
Matti J. Salmela ◽  
Kathleen Greenham ◽  
C. Robertson McClung ◽  
John H. Willis
Keyword(s):  
Genetic Variation ◽  
Circadian Clock ◽  
Sierra Nevada ◽  
Population Differentiation ◽  
Plant Traits ◽  
Population Level ◽  
Day Length ◽  
Circadian Period ◽  
Population Means ◽  
Seasonal Responses

Environmental variation along an elevational gradient can yield phenotypic differentiation resulting from varying selection pressures on plant traits related to seasonal responses. Thus, genetic clines can evolve in a suite of traits, including the circadian clock, that drives daily cycling in varied traits and that shares its genetic background with adaptation to seasonality. We used populations of annual Mimulus laciniatus from different elevations in the Sierra Nevada in California to explore among-population differentiation in the circadian clock, flowering responses to photoperiod, and phenological traits (days to cotyledon emergence, days to flowering, and days to seed ripening) in controlled common-garden conditions. Further, we examined correlations of these traits with environmental variables related to temperature and precipitation. We observed that the circadian period in leaf movement was differentiated among populations sampled within about 100 km, with population means varying by 1.6 h. Significant local genetic variation occurred within 2 populations in which circadian period among families varied by up to 1.8 h. Replicated treatments with variable ecologically relevant photoperiods revealed marked population differentiation in critical day length for flowering that ranged from 11.0 to 14.1 h, corresponding to the time period between late February and mid-May in the wild. Flowering time varied among populations in a 14-h photoperiod. Regardless of this substantial population-level diversity, obvious linear clinality in trait variability across elevations could not be determined based on our genotypic sample; it is possible that more complex spatial patterns of variation arise in complex terrains such as those in the Sierra Nevada. Moreover, we did not find statistically significant bivariate correlations between population means of different traits. Our research contributes to the understanding of genetic variation in the circadian clock and in seasonal responses in natural populations, highlighting the need for more comprehensive investigations on the association between the clock and other adaptive traits in plants.

scholarly journals Aedes (Finlaya) japonicus(Diptera: Culicidae), a Newly Recognized Mosquito in the United States: Analyses of Genetic Variation in the United States and Putative Source Populations

2001 ◽  
Vol 38 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Dina M. Fonseca ◽  
Scott Campbell ◽  
Wayne J. Crans ◽  
Motoyoshi Mogi ◽  
Ichiro Miyagi ◽  
...  
Keyword(s):  
United States ◽  
Genetic Variation ◽  
The United States ◽  
Source Populations

scholarly journals Combining superior alleles from two homozygous populations in a cross-fertilizing species

1980 ◽  
Vol 36 (3) ◽  
pp. 277-287 ◽  
Author(s):  
Y. T. Ho ◽  
R. E. Comstock
Keyword(s):  
Real Life ◽  
The Other ◽  
Relative Fitness ◽  
Source Population ◽  
Effective Population ◽  
Complete Dominance ◽  
Selection Limit ◽  
The Difference ◽  
Source Populations ◽  
Foundation Stock

SUMMARYThe issue of incorporating the good alleles from two homozygous populations of a cross-fertilizing species into a single improved population was investigated assuming independent assortment, no epistasis, and either complete dominance (of the favourable or the unfavourable alleles) or additive genes. The selection limit in the foundation stock is a function of the effective population size (N), the proportion (x) contributed by the better source population (P1), the difference in relative fitness between single locus homozygotes and the proportion of loci (that will segregate in the foundation stock) fixed favourably in P1. In real life the last two of these are never known. We therefore focused on the response limits given x = 0·5, 0·75, 0·875 or the optimum value of x (which is a function of the other three parameters). Our general finding was that in situations where N is large enough so that a major portion of the potential can be achieved, the F2 population should be used as the foundation stock when the two source populations do not differ greatly in performance; but when one population performs considerably better than the other, the first backcross (but not second backcross) would be the choice.

scholarly journals Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

Oecologia ◽  
2008 ◽  
Vol 158 (3) ◽  
pp. 411-419 ◽  
Author(s):  
T. van der Heide ◽  
A. J. P. Smolders ◽  
B. G. A. Rijkens ◽  
E. H. van Nes ◽  
M. M. van Katwijk ◽  
...  
Keyword(s):  
Zostera Marina ◽  
Shoot Density ◽  
Reduced Nitrogen

scholarly journals High-Level Genetic Diversity but No Population Structure Inferred from Nuclear and Mitochondrial Markers of the Peritrichous Ciliate Carchesium polypinum in the Grand River Basin (North America)

2009 ◽  
Vol 75 (10) ◽  
pp. 3187-3195 ◽  
Author(s):  
E. Gentekaki ◽  
D. H. Lynn
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
River Basin ◽  
Large Subunit ◽  
Population Level ◽  
Nuclear Markers ◽  
Mitochondrial Markers ◽  
Intraspecific Genetic Variation ◽  
Grand River

ABSTRACT Studies that assess intraspecific genetic variation in ciliates are few and quite recent. Consequently, knowledge of the subject and understanding of the processes that underlie it are limited. We sought to assess the degree of intraspecific genetic variation in Carchesium polypinum (Ciliophora: Peritrichia), a cosmopolitan, freshwater ciliate. We isolated colonies of C. polypinum from locations in the Grand River basin in Southwestern Ontario, Canada. We then used the nuclear markers—ITS1, ITS2, and the hypervariable regions of the large subunit rRNA—and an 819-bp fragment of the mitochondrial cytochrome c oxidase I gene (cox-1) to investigate the intraspecific genetic variation of C. polypinum and the degree of resolution of the above-mentioned markers at the population level. We also sought to determine whether the organism demonstrated any population structure that mapped onto the geography of the region. Our study shows that there is a high degree of genetic diversity at the isolate level, revealed by the mitochondrial markers but not the nuclear markers. Furthermore, our results indicate that C. polypinum is likely not a single morphospecies as previously thought.

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