Genetics.. Blood Types

Are you and your sister naturally born from both of your parents?

Are you the same gender as your twin? If you aren't, then the answer is that you're not identical.

If she is your identical twin (and you're both female), if she has a different blood type then you're not identical? The answer is no.

"Since identical twins come from the same fertilized egg, they have the exact same DNA. They are always of the same sex and they have the same blood type. Testing the DNA of twins is one way to determine if they are identical or fraternal. "

I'll leave it someone else to tell you definitively whether or not about parental-child blood type difference possibilities. My guess is that ... yes, that you can have parents who are both B and you be an O type - because the O type is a recessive gene., but as I said, that's a guess on my part.

Hi amtotheber,
When parents(both) have B+ blood group the possibilities of baby blood group is B+ or O...There is possibilities for twins have different blood group...

Ragman is correct. If you are identical twins then you will have identical blood types. If you are fraternal twins (two eggs and two sperm) then you can have a type O gene from each parent even if they are both type B. They would each have to be carrying a type O gene as well in order for you to get one from each parent (BO) + (BO) can yield offspring of (BO) (BB) and (OO). Only genetic types (OO) will test as type O. Carrying one or two copies of the type B gene will type as B.

http://genetics.thetech.org/ask-a-geneticist/twins-different-blood-types
Refer this link it explain the possibilities of twins have different blood groups

Are you saying identical twins can have different blood types?

I just read the link and found some interesting identical twin info, but it requires an extremely rare DNA mutation.

" It is a different story if the twins are identical. Identical twins come from the same egg and the same sperm and so share nearly identical DNA. For identical twins to have different blood types, something needs to happen to one twin’s DNA.

Small changes in DNA can and do happen so identical twins do have a few differences. What makes them having different blood types so rare is that the changes have to be in just the right place out of over six billion different possible places. The odds are very much against this happening but still, it is theoretically possible."[/i]