Genetics
A beginner’s guide to understanding the 3 commonly studied forms of genetic epistasis: recessive epistasis, duplicative recessive epistasis (aka “genes in the same pathway”), and dominant epistasis. Examples of the phenotype ratios generated by each are provided via simple gene pathway flowcharts.
Complementation Tests are a classic means by which geneticists can identify whether a mutant phenotype is due to one or more gene mutations. This guide explains both how to conduct a complementation test and the reasoning for drawing different conclusions.
Understanding Mendelian genotype and phenotype ratios is a key part of beginner’s genetics, and Punnett Squares help a great deal with this. However, when more than 2 genes are involved, Punnett Squares become impractical. This diagram depicts how to use the “Branch Line Method” to identify all possible phenotype ratios for a given parental cross.
When we conduct a cross and obtain non-mendelian phenotype ratios, it is possible that we are dealing with linked genes (genes that are on the same chromosome). The order of these genes on the chromosome can be mapped via recombination frequencies. This guide describes the “table method” of identifying recombinants, and how to map gene order on a chromosome.
This series of slides depicts simplified, step-by-step cartoons of how the process of mRNA transcription proceeds in both prokaryotes and eukaryotes. Understanding the core steps of initiation, elongation, and termination is the primary focus.
Bacterial operons are a classic way to study mechanisms for transcription regulation. This series of slides provides an annotated overview of 3 major operons commonly taught in intro genetics: the Lac Operon, the Arabinose Operon, and the Tryptophan Operon.
Statistics
A basic introduction and step by step guide to using Chi-square Goodness of Fit Tests, using Mendelian genotype and phenotype ratios as examples.
An additional elaboration of the basic Chi-square guide that elaborates on how small sample sizes can result in unexpected phenotype ratios in offspring due to the role of random chance. A coin flipping experiment and a human pedigree provide examples.