Chi-Square analysis of two point test cross data

By Bob Sheehy

Radford University

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This flash tutorial simulates analysis of a 2 point test cross and will walk you through the analysis of two hypothetical traits. Your goal is to determine if these traits are assorting independently of each other (as predicted by Mendel) or if they are linked. If they appear linked you will then be asked to determine the genetic distance between the genes encoding the two traits. You will be presented with an initial cross between two, true breeding (homozygous) individuals. From the information provided you must determine the dominant character state for each of two traits, devise a one letter gene symbols for each trait and, using your gene symbols determine genotypes for parents and F1 individuals. You will be asked to set up a test cross, and then use the X2 test to determine if the results of the cross vary significantly from what is expected for unlinked genes. Finally, you will determine the genetic distance between the two loci. Before proceeding it may help to review information on the analysis of test crosses and/or using X2 to test for independent assortment of genes

Cite this work

Researchers should cite this work as follows:

  • Sheehy, R.R. (2014): Chi-Square analysis of  two point test cross data, a simulation.