bloodsnake

behaps Cis AB is involved somehow ?

How is this possible , for example theoretical family both parents with AB x AB blood type get 1/4 children with genotype B-blood type and rest with AB blood type. where are going childern with AA blood type ? Are there some other locuses involved like H locus what can make childern with bombey blood type or something like that ? It Cant be that just A blood type didnt born.