Cone serotiny and inbreeding in natural populations of Pinus banksiana and Pinus contorta

1970 ◽  
Vol 48 (10) ◽  
pp. 1805-1809 ◽  
Author(s):  
A. H. Teich
Keyword(s):  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Environmental Influence ◽  
Single Gene ◽  
Marker Gene ◽  
Natural Populations ◽  
Inbreeding Coefficient ◽  
Gene Frequencies ◽  
Progeny Tests ◽  
Individual Trees

Cone serotiny in jack and lodgepole pine was studied by applying the Hardy–Weinberg law to data from several populations, and by examining data on progeny of individual trees. Cone serotiny appears to be governed by a single gene with two alleles. The phenotype of the heterozygote is intermediate to that of both homozygotes and is subject to environmental influence. Because of this a proportion of the heterozygotes may have been misidentified as homozygotes, which inflated the inbreeding coefficient, making it unreliable. Progeny tests or other means of correctly identifying heterozygotes would allow the use of cone serotiny as a marker gene for hybridization and relate populations by their similarity of gene frequencies.

Mating patterns in self-compatible distylous populations of Amsinckia (Boraginaceae)

1975 ◽  
Vol 53 (8) ◽  
pp. 773-779 ◽  
Author(s):  
Fred R. Ganders
Keyword(s):  
Random Mating ◽  
Marker Gene ◽  
Natural Populations ◽  
Breeding Systems ◽  
High Rate ◽  
Structure Population ◽  
Disassortative Mating ◽  
Progeny Tests ◽  
Flower Form ◽  
Two Populations

Progeny tests of naturally pollinated pin- and thrum-form plants of two species of Amsinckia were conducted to determine whether net selfing, random mating, or net disassortative mating occurred in natural populations. The locus determining flower form was used as a marker gene. Amsinckia spectabilis experienced close to random mating in a dense population, but in a small, diffuse population a high rate of selfing was indicated. Pin plants of Amsinckia vernicosa var. furcata experienced 44.3% net disassortative mating, and thrum plants in this species experienced complete (100%) disassortative mating.Compared with A. spectabilis, stigmas and anthers are about twice as far apart in A. vernicosa var. furcata; yet the pollinators are essentially similar, suggesting that greater separation of stigmas and anthers greatly improves the efficiency of distyly at promoting disassortative pollination. The two populations of A. spectabilis studied indicate that autogamy and (or) geitonogamy is much higher in diffuse populations. The results support previous studies that disassortative pollination is greater in thrum-form flowers than in pin flowers. Distyly without self-incompatibility can be an effective outbreeding system but is much more sensitive to variations in floral structure, population density, and pollinator behavior than are self-incompatible breeding systems.

scholarly journals Rating Introgression between Lodgepole and Jack Pine at the Individual Tree Level Using Morphological Traits

2011 ◽  
Vol 28 (3) ◽  
pp. 138-145 ◽  
Author(s):  
Katherine P. Bleiker ◽  
Allan L. Carroll
Keyword(s):  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Morphological Traits ◽  
Function Analysis ◽  
Introgressive Hybridization ◽  
Principal Component ◽  
Jack Pine ◽  
Tree Level ◽  
Individual Tree ◽  
Individual Trees

Abstract Introgressive hybridization between species generates novel gene combinations and phenotypes. We required an accessible, objective method of rating introgression between lodgepole pine (Pinus contorta var. latifolia [Engelm.] Critchfield) and jack pine (Pinus banksiana Lamb.) for individual trees where their ranges overlap in Canada for use in another study on host species effects on resistance to an eruptive herbivore that has recently expanded its range. We adapted, simplified, and fully quantified a morphological index developed to rate introgression of pine populations and applied it to individual trees. In addition to principal component analysis (PCA), we also used discriminant function analysis (DFA), a potentially more powerful method given a priori knowledge of parent taxa, to generate introgression ratings. Among-tree variation in morphological traits and introgression was high at sites within the hybrid zone but very low at pure parent sites. PCA and DFA produced similar introgression ratings at the stand level, but ratings differed substantially for some individual trees. Certain morphological traits may be omitted from both PCA and DFA with little impact on stand-level ratings. The discriminant functions presented here are based on easy-to-measure, fully quantifiable morphological traits and can be used by other researchers to produce relative introgression ratings for lodgepole and jack pine. The approach may also be applied to other plant hybrid systems.

scholarly journals Paternally inherited chloroplast polymorphism in Pinus: estimation of diversity and population subdivision, and tests of disequilibrium with a maternally inherited mitochondrial polymorphism.

Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 1187-1194
Author(s):  
J Dong ◽  
D B Wagner
Keyword(s):  
Chloroplast Dna ◽  
Restriction Fragment ◽  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Natural Populations ◽  
Jack Pine ◽  
Convincing Evidence ◽  
Population Subdivision ◽  
Dna Restriction

Abstract We have surveyed a chloroplast DNA restriction fragment length polymorphism in 745 individuals, distributed rangewide in eight allopatric natural populations of jack pine (Pinus banksiana Lamb.) and eight allopatric natural populations of lodgepole pine (Pinus contorta Dougl.). The polymorphic region of the chloroplast genome is located near duplicated psbA genes. Fourteen length variants were found in the survey, and these variants distinguished the two species qualitatively. Variant diversities were high in both species (hes = 0.43 in jack pine; hes = 0.44 in lodgepole pine). Population subdivision was weak within and among lodgepole pine subspecies and in jack pine (i.e., theta values were less than 0.05). This weak subdivision is compatible with theoretical predictions for paternally inherited markers in wind-pollinated outcrossers, as well as for polymorphisms with high length mutation rates. If these populations are at a drift-migration equilibrium, the chloroplast DNA restriction fragment data and previous mitochondrial frequency data from the same individuals are consistent with gene flow that is differential through seeds and pollen. The new data have permitted the first empirical tests of disequilibrium between maternally and paternally inherited factors. As expected, these tests failed to detect convincing evidence of nonrandom association between chloroplast and mitochondrial variants.

Update on the Boundaries of the Curly Birch Range

2020 ◽  
pp. 9-21
Author(s):  
L.V. Vetchinnikova ◽  
◽  
A.F. Titov ◽  
◽  
Keyword(s):  
Population Size ◽  
Natural Populations ◽  
Forest Tree ◽  
Published Data ◽  
Population Approach ◽  
Key Factors ◽  
History Of ◽  
Individual Trees ◽  
Karelian Birch

The article reports on the application of the best known principles for mapping natural populations of curly (Karelian) birch Betula pendula Roth var. carelica (Mercklin) Hämet-Ahti – one of the most appealing representatives of the forest tree flora. Relying on the synthesis and analysis of the published data amassed over nearly 100 years and the data from own full-scale studies done in the past few decades almost throughout the area where curly birch has grown naturally, it is concluded that its range outlined in the middle of the 20th century and since then hardly revised is outdated. The key factors and reasons necessitating its revision are specified. Herewith it is suggested that the range is delineated using the population approach, and the key element will be the critical population size below which the population is no longer viable in the long term. This approach implies that the boundaries of the taxon range depend on the boundaries of local populations (rather than the locations of individual trees or small clumps of trees), the size of which should not be lower than the critical value, which is supposed to be around 100–500 trees for curly birch. A schematic map of the curly birch range delineated using this approach is provided. We specially address the problem of determining the minimum population size to secure genetic diversity maintenance. The advantages of the population approach to delineating the distribution range of curly birch with regard to its biological features are highlighted. The authors argue that it enables a more accurate delineation of the range; shows the natural evolutionary history of the taxon (although it is not yet officially recognized as a species) and its range; can be relatively easily updated (e.g. depending on the scope of reintroduction); should be taken into account when working on the strategy of conservation and other actions designed to maintain and regenerate this unique representative of the forest tree flora.

Spatial Patterns of Chloroplast DNA and Cone Morphology Variation within Populations of a Pinus banksiana-Pinus contorta Sympatric Region

1991 ◽  
Vol 138 (1) ◽  
pp. 156-170 ◽  
Author(s):  
David B. Wagner ◽  
Zhong-Xu Sun ◽  
Diddahally R. Govindaraju ◽  
Bruce P. Dancik
Keyword(s):  
Chloroplast Dna ◽  
Spatial Patterns ◽  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Cone Morphology

scholarly journals Polygenic and single gene responses to selection for resistance to diazinon in Lucilia cuprina.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 613-620 ◽  
Author(s):  
J A McKenzie ◽  
A G Parker ◽  
J L Yen
Keyword(s):  
Resistant Strain ◽  
Single Gene ◽  
Natural Populations ◽  
Susceptible Strain ◽  
Selection Line ◽  
Base Population ◽  
Gene Response ◽  
Biochemical Profiles ◽  
Resistant Strains ◽  
Selection For

Abstract Following mutagenesis with ethyl methanesulfonate, selection in a susceptible strain with a concentration of the insecticide diazinon (0.0004%, w/v) above that required to kill 100% of the susceptible strain, the LC100 of that strain, resulted in a single gene response. The resultant four mutant resistant strains have equivalent physiological, genetical and biochemical profiles to a diazinon-resistant strain derived from a natural population and homozygous for the Rop-1 allele. Modification of the microsomal esterase E3 is responsible for resistance in each case. The Rop-1 locus maps approximately 4.4 map units proximal to bu on chromosome IV. Selection within the susceptible distribution, at a concentration of diazinon [0.0001% (w/v)] less than the LC100, resulted in a similar phenotypic response irrespective of whether the base population had been mutagenized. The responses were polygenically based, unique to each selection line and independent of Rop-1. The relevance of the results to selection for insecticide resistance in laboratory and natural populations is discussed.

Spatial genetic substructure within natural populations of jack pine (Pinus banksiana)

1991 ◽  
Vol 69 (3) ◽  
pp. 547-551 ◽  
Author(s):  
Chang Yi Xie ◽  
Peggy Knowles
Keyword(s):  
Spatial Autocorrelation ◽  
Pinus Banksiana ◽  
Pollen Dispersal ◽  
Natural Populations ◽  
Jack Pine ◽  
Spatial Autocorrelation Analysis ◽  
Autocorrelation Analysis ◽  
Long Distance ◽  
Genetic Substructure ◽  
Good Agreement

Spatial autocorrelation analysis was used to investigate the geographic distribution of allozyme genotypes within three natural populations of jack pine (Pinus banksiana Lamb.). Results indicate that genetic substructuring within these populations is very weak and the extent differs among populations. These results are in good agreement with those inferred from mating-system studies. Factors such as the species' predominantly outbreeding system, high mortality of selfs and inbreds prior to reproduction, long-distance pollen dispersal, and the absence of strong microhabitat selection may be responsible for the observed weak genetic substructuring. Key words: jack pine, Pinus banksiana, genetic substructure, allozyme, spatial autocorrelation analysis.

NUMERICAL ANALYSIS OF RANDOM DRIFT IN A CLINE

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 497-517
Author(s):  
Thomas Nagylaki ◽  
Bradley Lucier
Keyword(s):  
Natural Populations ◽  
The Other ◽  
Random Genetic Drift ◽  
Gene Frequencies ◽  
Random Drift ◽  
Linear Habitat ◽  
Asymptotic Formulae ◽  
A Chain ◽  
Average Position ◽  
Uniform Population

ABSTRACT The equilibrium state of a diffusion model for random genetic drift in a cline is analyzed numerically. The monoecious organism occupies an unbounded linear habitat with constant, uniform population density. Migration is homogeneouq symmetric and independent of genotype. A single diallelic locus with a step environment is investigated in the absence of dominance and mutation. The flattening of the expected cline due to random drift is very slight in natural populations. The ratio of the variance of either gene frequency to the product of the expected gene frequencies decreases monotonically to a nonzero constant. The correlation between the gene frequencies at two points decreases monotonically to zero as the separation is increased with the average position fixed; the decrease is asymptotically exponential. The correlation decreases monotonically to a positive constant depending on the separation as the average position increasingly deviates from the center of the cline with the separation fixed. The correlation also decreases monotonically to zero if one of the points is fixed and the other is moved outward in the habitat, the ultimate decrease again being exponential. Some asymptotic formulae are derived analytically.—The loss of an allele favored in an environmental pocket is investigated by simulating a chain of demes exchanging migrants, the other assumptions being the same as above. For most natural populations, provided the allele would be maintained in the population deterministically, this process is too slow to have evolutionary importance.

scholarly journals Cascabel: A Scalable and Versatile Amplicon Sequence Data Analysis Pipeline Delivering Reproducible and Documented Results

2020 ◽  
Vol 11 ◽  
Author(s):  
Alejandro Abdala Asbun ◽  
Marc A. Besseling ◽  
Sergio Balzano ◽  
Judith D. L. van Bleijswijk ◽  
Harry J. Witte ◽  
...  
Keyword(s):  
Data Analysis ◽  
Sequence Data ◽  
Single Gene ◽  
Marker Gene ◽  
Gene Sequencing ◽  
Data Generation ◽  
Clustering Methods ◽  
Analysis Pipeline ◽  
Data Analysis Pipeline ◽  
Marker Gene Sequencing

Marker gene sequencing of the rRNA operon (16S, 18S, ITS) or cytochrome c oxidase I (CO1) is a popular means to assess microbial communities of the environment, microbiomes associated with plants and animals, as well as communities of multicellular organisms via environmental DNA sequencing. Since this technique is based on sequencing a single gene, or even only parts of a single gene rather than the entire genome, the number of reads needed per sample to assess the microbial community structure is lower than that required for metagenome sequencing. This makes marker gene sequencing affordable to nearly any laboratory. Despite the relative ease and cost-efficiency of data generation, analyzing the resulting sequence data requires computational skills that may go beyond the standard repertoire of a current molecular biologist/ecologist. We have developed Cascabel, a scalable, flexible, and easy-to-use amplicon sequence data analysis pipeline, which uses Snakemake and a combination of existing and newly developed solutions for its computational steps. Cascabel takes the raw data as input and delivers a table of operational taxonomic units (OTUs) or Amplicon Sequence Variants (ASVs) in BIOM and text format and representative sequences. Cascabel is a highly versatile software that allows users to customize several steps of the pipeline, such as selecting from a set of OTU clustering methods or performing ASV analysis. In addition, we designed Cascabel to run in any linux/unix computing environment from desktop computers to computing servers making use of parallel processing if possible. The analyses and results are fully reproducible and documented in an HTML and optional pdf report. Cascabel is freely available at Github: https://github.com/AlejandroAb/CASCABEL.

scholarly journals Comparative genomics of the mimicry switch in Papilio dardanus

2014 ◽  
Vol 281 (1787) ◽  
pp. 20140465 ◽  
Author(s):  
Martijn J. T. N. Timmermans ◽  
Simon W. Baxter ◽  
Rebecca Clark ◽  
David G. Heckel ◽  
Heiko Vogel ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Single Gene ◽  
Natural Populations ◽  
Evolutionary Genetics ◽  
Artificial Chromosome ◽  
Wing Pattern ◽  
Nucleotide Polymorphisms ◽  
Physical Constraints ◽  
Transcription Factor Genes ◽  
Conserved Gene

The African Mocker Swallowtail, Papilio dardanus , is a textbook example in evolutionary genetics. Classical breeding experiments have shown that wing pattern variation in this polymorphic Batesian mimic is determined by the polyallelic H locus that controls a set of distinct mimetic phenotypes. Using bacterial artificial chromosome (BAC) sequencing, recombination analyses and comparative genomics, we show that H co-segregates with an interval of less than 500 kb that is collinear with two other Lepidoptera genomes and contains 24 genes, including the transcription factor genes engrailed ( en ) and invected ( inv ). H is located in a region of conserved gene order, which argues against any role for genomic translocations in the evolution of a hypothesized multi-gene mimicry locus. Natural populations of P. dardanus show significant associations of specific morphs with single nucleotide polymorphisms (SNPs), centred on en . In addition, SNP variation in the H region reveals evidence of non-neutral molecular evolution in the en gene alone. We find evidence for a duplication potentially driving physical constraints on recombination in the lamborni morph. Absence of perfect linkage disequilibrium between different genes in the other morphs suggests that H is limited to nucleotide positions in the regulatory and coding regions of en . Our results therefore support the hypothesis that a single gene underlies wing pattern variation in P. dardanus .

Sign in / Sign up

Export Citation Format

Share Document