One of the processes that ultimately provides for new combinations of alleles in sexually-reproducing organisms is the independent assortment
of chromosomes during meiosis 1.
Chi-squared tests will be performed to determine if the observed number of plants with a particular phenotype equals the expected for independent assortment
indicating whether or not the gps loci is linked to that particular trait.
The two examples that come readily to mind are the Hardy-Weinberg law that applies to ratios of genes in a population under particular conditions and the law of independent assortment
of chromosomes applied to the partitioning of chromosomes during meiosis.
The dihybrid cross was the way he established his second law of heredity: the principle of independent assortment