Spatio-temporal microdifferentiation of water-strider (Gerris) populations

SUMMARYSpatial and temporal differentiation in Gerris lacustris and G. odontogaster (Heteroptera, Gerridae) were studied in restricted areas, where one population of each species was subdivided into several subpopulations. The aim of the study was to relate genetic population parameters to ecological population structure studied by mark-recapture methods in the same pond systems. Marked differentiation between the subpopulations and significant enzyme allele frequency changes between subsequent generations were found at several loci. It is suggested that non-selective forces are a sufficient explanation for the observed differences.

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Faculty Opinions recommendation of Predictable allele frequency changes due to habitat fragmentation in the Glanville fritillary butterfly.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726165782.793522983 ◽

2016 ◽

Author(s):

Ian Wang

Keyword(s):

Habitat Fragmentation ◽

Allele Frequency ◽

Glanville Fritillary Butterfly ◽

Frequency Changes

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99 Breed authentication of five lines comparing Structure, Admixture, and an allele frequency method

Journal of Animal Science ◽

10.1093/jas/skaa054.044 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 25-25

Author(s):

Austin M Putz ◽

Patrick Charagu ◽

Abe Huisman

Keyword(s):

Population Structure ◽

Allele Frequency ◽

Regression Coefficients ◽

Frequency Method ◽

Large White ◽

Reference Allele ◽

Software Packages ◽

The Matrix ◽

Snp Panel ◽

Compare And Contrast

Abstract Two commonly used population structure software packages are freely available for breed authentication, Structure and Admixture. Structure uses a Bayesian approach to model population structure, while Admixture uses a frequentist approach. More recently, an allele frequency method has been updated to use quadratic programming to constrain the multiple linear regression coefficients of the regression of genotype count (divided by two) on the matrix of allele frequencies for each known breed or line. This constraint forced coefficients to sum to one and be greater than or equal to 0 and less than or equal to 1. The goal of this research was to compare and contrast these three methods to determine the breed/line authenticity for each of the five genetic lines. These five lines included Large White, Landrace, a lean Duroc, a meat quality Duroc, and a Pietrain line. Only animals with a 50K SNP panel were used in this analysis. Analyses were run five times for Structure and Admixture to check repeatability. The allele frequency method did not need to be repeated because it remains the same as long as the reference allele frequency matrix stays constant. For Structure, results of breed composition were inconsistent across replicates. Structure separated at least one of the maternal lines in three out of the five replicates with only 500 animals and kept the Duroc lines together as one population. Only 500 animals could be utilized in each run of Structure due to computational restraints. Admixture was very consistent across runs for each animal, but also failed to separate the two Duroc lines, instead splitting one of the two maternal lines. Finally, the allele frequency method split all five lines correctly and was 100% reproducible as long as the reference allele frequency matrix stays the same across runs.

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