In order to determine how many different genotypes are possible, you must first determine how many different gametes are possible for each parent, then match all the gametes in a genetic checkerboard. Although the three pairs of genes are linked to one homologous pair of chromosomes, there are a total of eight different possible gametes for each parent: CDE, CDe, CdE, Cde, cDE, cDe, cdE, and cde. This number of gametes is based on all the total possible ways these genes can be inherited on each chromosome of homologous pair #1. [It is not based on the random assortment of these genes during meiosis in the parents because all three genes are closely linked together on the same chromosome; therefore, all three genes tend to appear together in the same two gametes: CDE and cde.] The possible different genotypes are shown in the following table: Gametes CDE CDe CdE Cde cDE cDe cdE cde
CDE CDE/CDE CDE/CDe CDE/CdE CDE/Cde CDE/cDE CDE/cDe CDE/cdE CDE/cde
CDe CDe/CDE CDe/CDe CDe/CdE CDe/Cde CDe/cDE CDe/cDe CDe/cdE CDe/cde
CdE CdE/CDE CdE/CDe CdE/CdE CdE/Cde CdE/cDE CdE/cDe CdE/cdE CdE/cde
Cde Cde/CDE Cde/CDe Cde/CdE Cde/Cde Cde/cDE Cde/cDe Cde/cdE Cde/cde
cDE cDE/CDE cDE/CDe cDE/CdE cDE/Cde cDE/cDE cDE/cDe cDE/cdE cDE/cde
cDe cDe/CDE cDe/CDe cDe/CdE cDe/Cde cDe/cDE cDe/cDe cDe/cdE cDe/cde
cdE cdE/CDE cdE/CDe cdE/CdE cdE/Cde cdE/cDE cdE/cDe cdE/cdE cdE/cde
cde cde/CDE cde/CDe cde/CdE cde/Cde cde/cDE cde/cDe cde/cdE cde/cde