BIST P8149 · Columbia University · 2026
Computational Vignettes¶
Short R notebooks connect population-genetic concepts to calculations that can be inspected, run, and changed.
Lecture 2¶
Learn the E and M steps with two groups and hidden labels.
Use allele counting and an HWE likelihood, then add genotyping error with latent genotypes and EM.
Change transition and emission assumptions, then watch how the posterior probabilities respond.
Use a copying model to connect haplotypes, linkage disequilibrium, recombination, hidden states, and genotype imputation.
Lecture 3¶
Use a small hidden Markov model to see why a run of matching markers supports a shared ancestral segment.
Follow a disease-associated marker through informative meioses and compare linked and unlinked models.
Compare IBD sharing among affected siblings with the Mendelian expectation.
Average genotype differences across independent SNPs and recover the expected kinship of unrelated pairs and siblings.
Lecture 5¶
Download the Homework 5 genotype archive.
Lecture 8¶
Lecture 10¶
How to use these notebooks¶
Each vignette starts from one question, identifies the methodological insight, and finishes with a worked example. Read the narrative first, then run the code from top to bottom. Change one assumption at a time and check which result changes.
The site displays saved notebook outputs. Each GitHub Pages build also runs the notebooks in a clean Pixi environment before publishing them.