Genetic architecture and adaptive landscape of interior lodgepole pine (Pinuscontorta ssp. latifolia) in Canada

1995 ◽  
Vol 25 (12) ◽  
pp. 2010-2021 ◽  
Author(s):  
Chang-Yi Xie ◽  
Cheng C. Ying
Keyword(s):  
Genetic Variation ◽  
Central Region ◽  
Population Differentiation ◽  
Genetic Architecture ◽  
Lodgepole Pine ◽  
Natural Populations ◽  
High Elevation ◽  
Population Variation ◽  
Adaptive Landscape ◽  
Growth And Survival

The genetic architecture and adaptive landscape of interior lodgepole pine (Pinuscontorta ssp. latifolia Engelm. ex S. Wats.) in Canada were investigated in a provenance–family plantation located in central British Columbia. Fifty-three natural populations were sampled from three geographic regions covering the entire Canadian range, and their performance in growth and survival was recorded periodically over 20 years. Test results indicate that genetic variation among regions and among populations within regions was highly significant in all the traits investigated and accounted for, respectively, 53% and 41% of the total genetic variation in growth and 41% and 54% in survival. Within-population variation was also significant in growth but not in survival. Interior lodgepole pine in the central region demonstrated less genetic variation than in the northern and southern regions at both the population and family levels. In addition, the proportion of genetic variation associated with population was lower in the central region than in the other regions. Population differentiation in both growth and survival showed discernible elevational and geographic patterns. Regression models describing these adaptive patterns accounted for more than 80% of the among-population variation, and their veracity was verified with independent data. Populations of northern, coastal–interior transition, and high-elevation origin tended to have smaller trees with higher mortality. However, the patterns were not linear but differed in slope and (or) direction among regions. The adaptedness of populations tended to decrease as they were farther away from their origin, with a few exceptions displaying broad adaptation across more than 3° of latitude. As the test proceeded, population differentiation became more evident and adaptive clines became steeper. Some practical implications of these findings have been discussed.

scholarly journals Host-pathogen coevolution increases genetic variation in susceptibility to infection

2018 ◽  
Author(s):  
Elizabeth ML Duxbury ◽  
Jonathan P Day ◽  
Davide Maria Vespasiani ◽  
Yannik Thüringer ◽  
Ignacio Tolosana ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Variants ◽  
Genetic Architecture ◽  
Natural Populations ◽  
Major Effect ◽  
Cross Infection ◽  
Host Susceptibility ◽  
Susceptibility To Infection ◽  
Host Parasite Interactions ◽  
Host Parasite

AbstractIt is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infection experiment involving four species of Drosophila and four host-specific viruses, we always found greater genetic variation in susceptibility to viruses that had coevolved with their host. We went on to examine the genetic architecture of resistance in one host species, finding that there are more major-effect genetic variants in coevolved host-parasite interactions. We conclude that selection by pathogens increases genetic variation in host susceptibility, and much of this effect is caused by the occurrence of major-effect resistance polymorphisms within populations.

scholarly journals Regional genetic diversity in circadian period in Boechera stricta populations is high relative to the global range of diversity in Arabidopsis

2021 ◽  
Author(s):  
Robby McMinn ◽  
Matti Salmela ◽  
Cynthia Weinig
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Significant Proportion ◽  
Natural Populations ◽  
Elevational Gradient ◽  
Environmental Data ◽  
Population Variation ◽  
Circadian Period ◽  
In The Wild ◽  
Boechera Stricta

Circadian clocks manifest adaptations to predictable 24-h fluctuations in the exogenous environment, but it has yet to be determined why the endogenous circadian period length in the wild varies genetically around the hypothesized optimum of 24 h. We quantified genetic variation in circadian period in leaf movement in 30 natural populations of the Arabidopsis relative Boechera stricta sampled within only 1° of latitude but across an elevational gradient spanning 2460−3300 m in the Rocky Mountains. Measuring over 3800 plants from 473 maternal families (7−20 per population), we found genetic variation that was of similar magnitude among vs. within populations, with population means varying between 21.9−24.9 h and maternal family means within populations varying by up to ~6 h. After statistically factoring out spatial autocorrelation at the habitat extremes, we found that elevation explained a significant proportion of genetic variation in circadian period such that higher-elevation populations had shorter mean period lengths and less within-population variation. Environmental data indicate that these spatial trends could be related to steep regional climatic gradients in temperature, precipitation, and their intra-annual variability. Our findings provide evidence that spatially fine-grained environmental heterogeneity contributes to naturally occurring genetic diversity in circadian traits in wild populations.

Variation in cedar leaf blight (Didymascella thujina) resistance of western redcedar (Thuja plicata)

2007 ◽  
Vol 37 (10) ◽  
pp. 1978-1986 ◽  
Author(s):  
John H. Russell ◽  
Harry H. Kope ◽  
Peter Ades ◽  
Heidi Collinson
Keyword(s):  
British Columbia ◽  
Genetic Correlations ◽  
Natural Populations ◽  
High Elevation ◽  
Leaf Blight ◽  
Population Variation ◽  
Thuja Plicata ◽  
Western Redcedar ◽  
Queen Charlotte Islands ◽  
River Site

Western redcedar ( Thuja plicata Donn ex D. Don) seedlings from a population study with family structure were planted at four sites across coastal British Columbia. All seedlings at the time of planting were infected with cedar leaf blight (CLB) ( Didymascella thujina (E.J. Durand) Maire). CLB severity and tree heights were measured at various ages from 2 to 12 years. There were significant site differences in CLB severity with the coastal hypermaritime site showing the most and with the submaritime site showing the least. Population differences in disease severity were evident with British Columbia coastal, low-elevation populations exhibiting the most resistance and with British Columbia high-elevation and California sources showing the least. Population resistance was consistent across all four sites (all r > 0.90, p < 0.001). Coefficients of additive genetic variation in CLB severity at all four sites varied from 13.2% to 20.1% with narrow-sense heritabilities from 0.21 to 0.66. Type B genetic correlations in CLB severity across sites averaged 0.59. Type A genetic correlations between 6 year CLB severity and height at the Jordan River site on western Vanvouver Island and at the site on the Queen Charlotte Islands were –0.96 and –0.86 (p < 0.001), respectively. Results are discussed with respect to climatic influences and prior exposure to CLB on among- and within-population variation in western redcedar natural populations and impact on gene resource management.

Population differentiation in lodgepole pine, Pinus contorta spp. latifolia: a discriminant analysis of allozyme variation

1985 ◽  
Vol 27 (2) ◽  
pp. 210-218 ◽  
Author(s):  
Francis C. Yeh ◽  
William M. Cheliak ◽  
Bruce P. Dancik ◽  
Keith Illingworth ◽  
Diane C. Trust ◽  
...  
Keyword(s):  
British Columbia ◽  
Genetic Variation ◽  
Discriminant Analysis ◽  
Genetic Differentiation ◽  
Population Differentiation ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Allozyme Variation ◽  
Discriminant Functions ◽  
Polymorphic Loci

Seeds from 17 populations representing most of the range of lodgepole pine in the Yukon and British Columbia were analyzed for electrophoretically demonstrable variation in 16 proteins coded by 23 genetic loci. Consistent with that reported on genetic variation in this conifer, on the average, 64% of the loci per population were polymorphic, and expected and observed heterozygosity per population were 0.165 and 0.174, respectively. Univariate F-ratio tests for homogeneity among populations indicated genetic differentiation (p < 0.05) at six loci. Two significant (p < 0.05) canonical discriminant functions accounted for 38% of the total variance in the 20 polymorphic loci. A rich structure of genetic variation associated with geography was revealed. Both latitude and altitude appeared to be important, with northern populations exhibiting a greater extent of genetic differentiation.Key words: allozymes, electromorphs, populations, Pinus, lodgepole pine.

scholarly journals Combining modelling, field data and genetic variation to understand the post-reintroduction population genetics of the Marsh Fritillary butterfly (Euphydryas aurinia)

2021 ◽  
Author(s):  
Michelle L. Davis ◽  
Carl Barker ◽  
Ian Powell ◽  
Keith Porter ◽  
Paul Ashton
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Evolutionary Dynamics ◽  
Captive Breeding ◽  
Natural Populations ◽  
Population Variation ◽  
Past Century ◽  
Euphydryas Aurinia ◽  
Founder Populations ◽  
Marsh Fritillary

Abstract The Marsh Fritillary butterfly (Euphydryas aurinia) is a Eurasian species which has suffered significant reductions in occurrence and abundance over the past century, particularly across the western side of its range, due to agricultural intensification and habitat loss. This loss has been particularly severe in the UK with extensive localised extinctions. Following sympathetic management, reintroduction was undertaken at four Cumbria (northern UK) sites in 2007 with stock from a captive admixture population descended from Cumbrian and Scottish founders. Annual population monitoring of the reintroductions was undertaken. Nine years post-reintroduction, the level of population genetic variation was assessed using microsatellites. Variation in historical Cumbrian samples was determined using museum samples and Scottish samples from current populations were assayed to characterise natural population variation. Half of the Scottish sites also served as indicators of the alleles present in the founder populations. The genetic contribution of the founder populations allied to population size data allowed patterns of genetic variation to be modelled. Alleles from Cumbrian and Scottish founders are present in the reintroduced populations. The four sites have levels of variation akin to natural populations and exhibit differentiation as predicted by statistical modelling and comparable with natural populations. This suggests that reintroduction following captive breeding can produce self-sustaining populations with natural levels of genetic diversity. These populations appear to be undergoing the same evolutionary dynamics with bottlenecks and drift as natural populations. Implications for insect conservation Reintroduction of captive bred individuals is a viable strategy for producing populations with natural levels of genetic diversity and evolutionary dynamics. Hybridisation of populations on the brink of extinction with those thriving can preserve some of the genetic distinctiveness of the declining population.

scholarly journals Host-pathogen coevolution increases genetic variation in susceptibility to infection

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Elizabeth ML Duxbury ◽  
Jonathan P Day ◽  
Davide Maria Vespasiani ◽  
Yannik Thüringer ◽  
Ignacio Tolosana ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Variants ◽  
Genetic Architecture ◽  
Natural Populations ◽  
Major Effect ◽  
Cross Infection ◽  
Host Susceptibility ◽  
Infection Experiment ◽  
Susceptibility To Infection ◽  
Host Pathogen

It is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infection experiment involving four species of Drosophila and four host-specific viruses, we always found greater genetic variation in susceptibility to viruses that had coevolved with their host. We went on to examine the genetic architecture of resistance in one host species, finding that there are more major-effect genetic variants in coevolved host-pathogen interactions. We conclude that selection by pathogens has increased genetic variation in host susceptibility, and much of this effect is caused by the occurrence of major-effect resistance polymorphisms within populations.

Allozyme variations in six natural populations of scots pine (Pinus sylvestris) in Turkey

Biologia ◽  
2007 ◽  
Vol 62 (6) ◽  
Author(s):  
Behiye Bilgen ◽  
Nuray Kaya
Keyword(s):  
Genetic Variation ◽  
Pinus Sylvestris ◽  
Genetic Distance ◽  
Scots Pine ◽  
Natural Populations ◽  
Mean Value ◽  
Population Variation ◽  
Starch Gel Electrophoresis ◽  
The Mean ◽  
Nei's Genetic Distance

AbstractGenetic variation in six natural populations of Scots pine (Pinus sylvestris L.) was determined with isoenzyme analyses. For this purpose, haploid female gametophytes of seeds and horizontal starch gel electrophoresis technique were used. A total of 17 loci and 58 alleles were observed in studying 10 enzyme systems. The average proportion of polymorphic loci for populations ranged from 58.8% to 70.6%. The average number of alleles per locus per population was 2.65. The mean estimated expected heterozygosity (He) of populations was 0.294. A rather high proportion of genetic diversity (96.4%) was due to within-population variation and the remaining (3.6%) was due to variation among populations. The level of gene flow (Nem) was found to be 6.69 per generation. Nei’s genetic distance coefficient ranged from 0.006 to 0.027 (mean 0.017) among all possible population pairs. The mean value of Nei’s genetic distance is similar to the values reported for other European Scots pine populations. The low mean value of Nei’s genetic distance among populations is enough to explain low interpopulation variation. According to genetic variation parameters, three out of six populations (Akdagmadeni-Yozgat, Refahiye-Erzincan and Vezirkopru-Samsun) appear to be preferable populations for genetic conservation and forest tree breeding programs.

scholarly journals POPULATION GENETICS OF ALLOZYME VARIATION IN NEUROSPORA INTERMEDIA

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 785-805
Author(s):  
P T Spieth
Keyword(s):  
Genetic Variation ◽  
Vegetative Reproduction ◽  
Vascular Plant ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Regular Feature ◽  
Local Populations ◽  
Neurospora Intermedia ◽  
Pattern Of Variation ◽  
High Level

ABSTRACT Electrophoretically detectable variation in the fungus Neurospora intermedia has been surveyed among isolates from natural populations in Malaya, Papua, Australia and Florida. The principal result is a pattern of genetic variation within and between populations that is qualitatively no different than the well documented patterns for Drosophila and humans. In particular, there is a high level of genetic variation, the majority of which occurs at the level of local populations. Evidence is presented which argues that N. intermedia has a population structure analogous to that of an annual vascular plant with a high level of vegetative reproduction. Sexual reproduction appears to be a regular feature in the biology of the species. Substantial heterokaryon function seems unlikely in natural populations of N. intermedia. Theoretical considerations concerning the mechanisms underlying the observed pattern of variation most likely should be consistent with haploid selection theory. The implications of this constraint upon the theory are discussed in detail, leading to the presentation of a model based upon the concept of environmental heterogeneity. The essence of the model, which is equally applicable to haploid and diploid situations, is a shifting distribution of multiple adaptive niches among local populations such that a given population has a small net selective pressure in favor of one allele or another, depending upon its particular distribution of niches. Gene flow among neighboring populations with differing net selective pressures is postulated as the principal factor underlying intrapopulational allozyme variation.

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