Posts Tagged ‘ genetics ’

Polyploidy in sugarcane

September 28, 2011
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Polyploidy in sugarcane

While reading UseR conference abstracts I came across this sentence: "Sugarcane is polypoid, i.e., has 8 to 14 copies of every chromosome, with individual alleles in varying numbers." Vau! This generates really complex genotype system. Say we have bial...

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Setup up the inverse of additive relationship matrix in R

August 11, 2011
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Setup up the inverse of additive relationship matrix in R

Additive genetic covariance between individuals is one of the key concepts in (quantitative) genetics. When doing the prediction of additive genetic values for pedigree members, we need the inverse of the so called numerator relationship matr...

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gRain: genetics example

April 14, 2011
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gRain: genetics example

gRain is an R package for "probability propagation in graphical independence networks, also known as probabilistic expert systems (which includes Bayesian networks as a special case)". This package caught my attention because some genetic models can b...

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Drawing pedigree examples using the kinship R package

June 30, 2010
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Drawing pedigree examples using the kinship R package

I have previously provided sort of an overview about plotting the pedigrees, then specifically using the Graphiviz, while I have lately used the TikZ LaTeX (see slides 11-15) system (see more example). The later gives great (beautiful) results, but at ...

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Galton’s quincunx in R

December 13, 2009
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Galton’s quincunx in R

Andrej Blejec has a very nice R demo of Galton's quincunx (link1, link2). It is a bit tedious to copy the code from PDF to R console, but it is worth the effort as the demo simulation clearly shows the nature of quincunx. After a bit of search I also f...

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Additive vs. dominance two-allele genetic model by DIC

August 7, 2009
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Additive vs. dominance two-allele genetic model by DIC

Two-allele model has alleles A1 and A2 and genotypes A1A1, A1A2, and A2A2. This model can be fitted using only additive effect (restricted model) or additve+dominance effect. (full model) The later model has one parameter more than the former. I was us...

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Illinois long-term selection experiment for oil and protein in corn

February 22, 2009
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Illinois long-term selection experiment for oil and protein in corn

Researchers at the University of Illinois are conducting one of the longest experiments in biology - Illinois long-term selection experiment for oil and protein in corn. The experiment started in 1896 and is still active! In esence they are selecting l...

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MCMCglmm package for R

January 29, 2009
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MCMCglmm package for R

Jarrod Hadfield published MCMCglmm package on CRAN. The package can fit generalised linear mixed models via MCMC methods. Bellow is the abstract from the vignette. The list of supported models is quite impressive. Nice job Jarrod! This is not the first...

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