Package fitTetra contains three functions that can be used to assign genotypes to a collection of tetraploid samples based on bialleleic marker assays. Functions fitTetra (to fit several models for one marker from the data and select the best fitting) or saveMarkerModels (calls fitTetra for multiple markers and saves the results to files) will probably be the most convenient to use. Function CodomMarker offers more control and fits one specified model for a given marker.