if my blood ttyp[e is b negative and my dads is b positive then what does my mother have to be?

Answer 1

Yeah you could either be homozygous or heterozygous for B, meaning that you could have two genes for B, or one for B and one for O. So if you got the B from your dad, you could have either gotten a second B from your mom or a gene for O type blood.

Since your dad is positive and you are negative, he is heterozygous, meaning he has one gene for Rh positive and one for negative. You recieved the negative gene, and your mom could be either heterozygous positive or negative. Either way you got the recessive negative gene from your parents.

Actually it is also possible that your mom could be A, or even AB, there's no way of telling without testing her blood.

Answer 2

Your mom could be positive or negative, because we each have two genes for each of these traits, one we "show" and one we don't. Two positive parents CAN have an Rh negative child.

For example, each parent could have in their own DNA one positive and one negative gene for Rh factor. They each pass on one of those to their kid at random, the neg. or the pos. So the two parents could have positive blood themselves (because the one positive gene is dominant, & gives you what blood type you have, as long as you have any dominant genes yourself), but the kid could have negative if the parents each pass along the "hidden" negative gene (then kid has two negative genes and so is negative).

BTW, Jeff, awesome and accurate answer, esp. for someone your age!

Answer 3

Either O negative or B negative.

Answer 4

Either B or O, Rh negative.

Answer 5

It could be either o- or B-....you should ask your mom to get a blood test. also, the "B" has to be capitalized..."A" and "B" types are both dominant, and type "o" blood is recessive...the capital or lowercase letter indicates this property of the gene.