This problem involves matings on the ABO gene that determines the ABO blood type. Click on New Problem to start. The genotypes of two mates will be given on the second line. Calculate the genotypes of their offspring, the expected frequency of these genotypes, the phenotypes of the offspring, and the expected frequency of these phenotypes. Then enter your answers in the appropriate column. Note that the answers for the genotypes and phenotypes are case sensitive, so always use upper case letters for the ABO system. When you are finished click on the Submit Answer button. If you make a mistake, just correct the error and click on Submit Answer; you do not have to re-enter the whole answer again. If you cannot figure out the answer, click on the "I give up!" button.

Click on this link for a brief refresher on the ABO locus.