scholarly journals Evolution of multilocus genetic structure in an experimental barley population.

Genetics ◽  
1992 ◽  
Vol 131 (4) ◽  
pp. 957-969
Author(s):  
R W Allard ◽  
Q Zhang ◽  
M A Maroof ◽  
O M Muona
Keyword(s):  
Natural Selection ◽  
Genetic Structure ◽  
Quantitative Traits ◽  
Transition Period ◽  
Single Locus ◽  
Heterogeneous Environment ◽  
Number Of Clusters ◽  
Allelic Frequencies ◽  
Barley Population ◽  
Multilocus Genetic Structure

Abstract Data from 311 selfed families isolated from four generations (F8, F13, F23, F45) of an experimental barley population were analyzed to determine patterns of change in character expression for seven quantitative traits, and in single-locus allelic frequencies, and multilocus genetic structure, for 16 Mendelian loci that code for discretely recognizable variants. The analyses showed that large changes in single-locus allelic frequencies and major reorganizations in multilocus genetic structure occurred in each of the generation-to-generation transitions examined. Although associations among a few traits persisted over generations, dynamic dissociations and reassociations occurred among several traits in each generation-transition period. Overall, the restructuring that occurred was characterized by gradual decreases in the number of clusters of associated traits and increases in the number of traits within each cluster. The observed changes in single-locus frequencies and in multilocus genetic structure were attributed to interplay among various evolutionary factors among which natural selection acting in a temporally heterogeneous environment was the guiding force.

scholarly journals Evolution of multilocus genetic structure in Avena hirtula and Avena barbata.

Genetics ◽  
1993 ◽  
Vol 135 (4) ◽  
pp. 1125-1139 ◽  
Author(s):  
R W Allard ◽  
P García ◽  
L E Sáenz-de-Miera ◽  
M Pérez de la Vega
Keyword(s):  
Natural Selection ◽  
Genetic Structure ◽  
Allelic Diversity ◽  
Adaptive Landscape ◽  
Epistatic Interactions ◽  
Avena Barbata ◽  
Local Populations ◽  
Diploid Ancestor ◽  
Multilocus Genetic Structure

Abstract Avena barbata, an autotetraploid grass, is much more widely adapted than Avena hirtula, its diploid ancestor. We have determined the 14-locus genotype of 754 diploid and 4751 tetraploid plants from 10 and 50 Spanish sites, respectively. Allelic diversity is much greater in the tetraploid (52 alleles) than in the diploid (38 alleles): the extra alleles of the tetraploid were present in nonsegregating heteroallelic quadriplexes. Seven loci were monomorphic for the same allele (genotypically 11) in all populations of the diploid: five of these loci were also monomorphic for the same allele (genotypically 1111) in all populations of the tetraploid whereas two loci each formed a heteroallelic quadriplex (1122) that was monomorphic or predominant in the tetraploid. Seven of the 14 loci formed one or more highly successful homoallelic and/or heteroallelic quadriplexes in the tetraploid. We attribute much of the greater heterosis and wider adaptedness of the tetraploid to favorable within-locus interactions and interlocus (epistatic) interactions among alleles of the loci that form heteroallelic quadriplexes. It is difficult to account for the observed patterns in which genotypes are distributed ecogeographically except in terms of natural selection favoring particular alleles and genotypes in specific habitats. We conclude that natural selection was the predominant integrating force in shaping the specific genetic structure of different local populations as well as the adaptive landscape of both the diploid and tetraploid.

The Price Equation

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Natural Selection ◽  
Replicator Dynamics ◽  
Genetic Selection ◽  
Single Locus ◽  
Price Equation ◽  
General Description ◽  
Conceptual Tool ◽  
Evolutionary Selection ◽  
Selective Regime ◽  
Fisher’S Fundamental Theorem

This chapter considers a general description of natural selection: the Price equation. Developed by George Price in the late 1960s, the Price equation can be applied to the change of any quantity under any selective regime. It is thus not limited to considering simple haploid single-locus traits, unlike the replicator dynamics, and indeed it is not even limited to considering evolutionary selection. The Price equation provides an instantaneous description of selection in action. The simplicity of the equation makes it a useful conceptual tool for understanding selective processes such as natural selection. The chapter first describes the general Price equation before discussing its use to understand genetic selection. It then shows how the Price equation can be used to derive two classical results from population and quantitative genetics: Fisher's “fundamental theorem of natural selection” and the breeder's equation.

scholarly journals Patterns of Genome-Wide Variation, Population Differentiation and SNP Discovery of the Red Banded Stink Bug (Piezodorus guildinii)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria I. Zucchi ◽  
Erick M. G. Cordeiro ◽  
Clint Allen ◽  
Mariana Novello ◽  
João Paulo Gomes Viana ◽  
...  
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Genetic Structure ◽  
Insect Pests ◽  
Geographic Origin ◽  
The United States ◽  
Basic Knowledge ◽  
Stink Bug ◽  
Mixed Ancestry ◽  
Significant Genetic Structure

Abstract Unravelling the details of range expansion and ecological dominance shifts of insect pests has been challenging due to the lack of basic knowledge about population structure, gene flow, and most importantly, how natural selection is affecting the adaptive process. Piezodous guildinii is an emerging pest of soybean in the southern region of the United States, and increasingly important in Brazil in recent years. However, the reasons P. guildinii is gradually becoming more of a problem are questions still mostly unanswered. Here, we have genotyped P. guildinii samples and discovered 1,337 loci containing 4,083 variant sites SNPs that were used to estimate genetic structure and to identify gene candidates under natural selection. Our results revealed the existence of a significant genetic structure separating populations according to their broad geographic origin, i.e., U.S. and Brazil, supported by AMOVA (FGT = 0.26), STRUCTURE, PCA, and FST analyses. High levels of gene flow or coancestry within groups (i.e., within countries) can be inferred from the data, and no spatial pattern was apparent at the finer scale in Brazil. Samples from different seasons show more heterogeneous compositions suggesting mixed ancestry and a more complex dynamic. Lastly, we were able to detect and successfully annotated 123 GBS loci (10.5%) under positive selection. The gene ontology (GO) analysis implicated candidate genes under selection with genome reorganization, neuropeptides, and energy mobilization. We discuss how these findings could be related to recent outbreaks and suggest how new efforts directed to better understand P. guildinii population dynamics.

GENETIC STRUCTURE AND QUANTITATIVE TRAITS VARIATION IN F1 FULL-SIBS PROGENIES OF CASTANEA SATIVA MILL.

1999 ◽  
pp. 395-406 ◽  
Author(s):  
F. Villani ◽  
M. Lauteri ◽  
A. Sansotta ◽  
M. Cherubini ◽  
M.C. Monteverdi ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Quantitative Traits ◽  
Castanea Sativa ◽  
Castanea Sativa Mill

Natural Selection on Quantitative Traits in the Bombina Hybrid Zone

Evolution ◽  
1995 ◽  
Vol 49 (6) ◽  
pp. 1224 ◽  
Author(s):  
Beate Nurnberger ◽  
Nick Barton ◽  
Catriona MacCallum ◽  
Jason Gilchrist ◽  
Michael Appleby
Keyword(s):  
Natural Selection ◽  
Hybrid Zone ◽  
Quantitative Traits

Genetic structure of the western rock lobster, Panulirus cygnus, with the benefit of hindsight

1996 ◽  
Vol 47 (7) ◽  
pp. 889 ◽  
Author(s):  
AP Thompson ◽  
JR Hanley ◽  
MS Johnson
Keyword(s):  
Genetic Structure ◽  
Western Australia ◽  
Allozyme Variation ◽  
Genetic Homogeneity ◽  
Latitudinal Variation ◽  
Rock Lobster ◽  
Polymorphic Loci ◽  
Allelic Frequencies ◽  
Genetic Subdivision ◽  
Panulirus Cygnus

Allozyme variation was used to investigate the genetic structure of the western rock lobster, Panulirus cygnus, along the coast of Western Australia. The study involved genetic surveys in 1980 and 1994. The first survey showed strong suggestions of latitudinal variation at two polymorphic loci, EST and GPI, but these suggestions were statistically suspect. With the benefit of hindsight gained from 1980, the 1994 survey was designed to examine more directly the suggestion of latitudinal genetic subdivision in this species. No evidence of genetic subdivision was found at either the EST or the GPI locus. In addition, the average FST value over nine polymorphic loci was a very low 0.0002. The evidence is consistent with current interpretations that P. cygnus is a single, panmictic population. In contrast with this spatial genetic homogeneity, however, there were significant changes in allelic frequencies at the GPI locus between 1980 and 1994, indicating genetic differences among cohorts.

Sign in / Sign up

Export Citation Format

Share Document