How do you get a negative blood type
There is a 100% chance that dad will pass an O to his kids. Let’s focus first on the O part of the blood type.
This is easier than I am making it sound… One “easy” way to figure out the odds of having an O- baby in this case involves just multiplying the chances for each part of the blood type.
HOW DO YOU GET A NEGATIVE BLOOD TYPE HOW TO
Next I’ll show you how to figure out that 1 in 8 number for an O- baby. The baby will have a negative blood type. They both have a positive blood type but carry a hidden negative version of the gene.Īs you can see below, if they each happen to pass a negative, the child will end up with two negative copies of the gene. Now imagine two positive parents who both have one positive version of the RHD gene and one negative version. This means that these are the possible genes and their blood types: Genes The positive version is dominant over negative. This gene comes in two forms, “positive” and “negative”. Now we are ready to deal with the negative part of the blood type. The baby got an O from dad and an O from mom. I have shown him as OO.ĭad will always pass an O to his kids (that is all he has to give!) and mom will pass an A half the time and an O the other half of the time. People with an O blood type have two copies of the O version of the gene (though there are rare exceptions to this rule). We have a mom who has an A and an O version of the ABO gene. She has A blood type but is a carrier for O. This is why in the picture she is AO. Neither wins out over the other, which is where AB blood comes from. Here is what that means for blood type: Genes In the case of the ABO gene, A and B are dominant over O. In genetics-speak, these alleles are dominant over the recessive alleles. They are: GenesĪs I said, some gene versions can overpower other ones. Keeping in mind that we have two copies of the ABO gene, this means there are six different genetic combinations. The ABO gene comes in three different versions, A, B, and O. At the end, you’ll see how the baby ended up O- with an A+ mom and an O+ dad. The next step is seeing how these apply to the ABO and RHD genes.
Some gene versions can overpower others.Genes can come in different versions (or alleles).We pass one of our two copies (chosen at random) down to our child.We have two copies of most of our genes.In fact, we need to focus on four things: To explain what happened in your situation, we need to take a step back and think about our genes. The ABO gene is in charge of the A and O (and B and AB) parts of blood type and the RHD gene is responsible for the positive and negative parts. There is a separate gene for each part of the blood type we are discussing here. In the next couple of sections, I’ll explain what is going on and why each of their kids had a 1 in 8 chance for having an O- child. In the next couple of sections, I’ll explain what is going on and why each of their kids had a 1 in 8 chance for having an O- child.Īs you can probably tell, there is a lot going on here for something as seemingly simple as a blood type. Until you have a baby with that trait that is…Īs you can probably tell, there is a lot going on here for something as seemingly simple as a blood type. This means they can hide out in your DNA without you even knowing it. This is possible because both O and Rh- are something called recessive traits. Each of their kids has around a 1 in 8 chance of having O negative blood. What happened was that dad and mom each passed both an O and an Rh negative to the baby. In this case, the most likely explanation is that dad is a carrier for being Rh- and mom is a carrier for blood type O.