Originally posted by: Neela10
There are basically four primary common Blood types. The most common by far is Blood type O, followed by type A, type B, and the least common is Blood type AB.
Seems like you need to refresh your memory, each of receives one factor in blood group from mother and one from father. OO(basically O here is zero, means u didn't received any of A and B) is least comman blood type AA is most comman BB is next in the list but when one parent has blood group AA and another one has BB, all the childs will have blood type AB. This is simple mendelian genetics! blood group O needs to marry with blood group O to have childrens of blood group O. Blood group OO runs in a family since both parents need to have bloodgroup type OO in order to have these kids. But all other combinations will give rise to blood group A, B or AB. Regradless of commanality of blood group type AB, bloodgroup AB is universal acceptor they can take blood from almost anybody. (As long as Rhesus factor is matching +ive or -ive). And blood group O is universal donor(they can give blood to anybody as long as the -ive, +ive is matched)
Less comman is blood group are AO(a subtype of bloodgroup A) and BO (a subtype of blood group B). needless to say such blood type are formed when a bloodtype OO marries with AA or BB . since AO and BO behaves identical to AA and BB, such lineage is lost very quicky in general population. However once in a while a blood group AO might marry with BO and will have blood group OO offspring.
When a person with +ive blood group marries with -ive blood group person. Usually its difficult to conceive a child as mother's antibody harms fetus. But after the birth of 1st child, immunization level(antibody production) of mother increase multifold and its almost impossible to have another child.
Hope this clarifies your doubts.
Edited by nikumay2k - 14 years ago