If Both Parents Have the Same Blood Type Will the Baby
-A curious adult from Michigan
December six, 2016
While a child could have the aforementioned blood type as i of his/her parents, information technology doesn't ever happen that way. For example, parents with AB and O blood types can either have children with blood blazon A or blood type B. These two types are definitely unlike than parents' claret types!
Merely 2 O parents, for example, will pretty much always have O kids. They volition lucifer both parents.
As you tin can see, sometimes kids' blood types lucifer and sometimes they don't. At that place are certain genetics "rules" that allowed me to get to this answer, which I break down for you below. Merely like any good rules, at that place are exceptions.
See the links at the bottom on this page to previous answers that discuss some of these rule-breaker situations. Keep in listen though that they are very rare. Nigh all cases follow a set of genetics rules based on how genes are passed downwardly from parent to kid.
One Factor Can Lead to Iv Unlike Blood Types
Permit'southward start with Dna. Deoxyribonucleic acid has the instructions for making a living thing. So your DNA has instructions for making you.
Each specific instruction for a pocket-size part of you is called a gene. As humans, nosotros all accept the same 20,000 or then genes. What makes us different are the different versions of these genes.
For case, nosotros all have the blood blazon gene, ABO. What gives us unlike blood types is that this cistron comes in iii different versions: A, B, and O.
In a simple world, the three versions would give three blood types and a child would have one of the blood types of the parents. But nosotros don't live in a simple world, at present, do we?
There'south one more than thing we need to know near our genes- we accept two copies of most of them. We get ane copy from our mom and i from our dad. Each of your parents accept 2 copies of each of their genes, and they each pass i down to y'all.
Can you start to see how this may complicate things?
Since we get these genes from our parents, it is common to share certain traits with our parents, like blood type. Just like I said at the start, that'southward not ever the case.
Considering we accept 2 copies of the blood type gene and there are three possible versions of this gene, there are six possible combinations. Officially complicated! They are:
These are called blood type genotypes. They are all of the possible combinations of the 2 gene versions together.
Ok and then nosotros have six combinations and only four blood types. Lets encounter why that is.
Cistron-Protein Human relationship
I told you there are all these different genes and that they come in versions. But what exactly do they practise and what is different most them?
Genes are the instructions for proteins. And different cistron versions make unlike versions of a poly peptide.
And then the A version of the ABO genes makes the "A" version of a protein, the B version a B version of a protein and importantly, for our word, the O version doesn't brand either.
Your blood type is determined by which of these proteins y'all actually make. This is why in that location are four different blood types.
Retrieve our 6 genetic combinations, or genotypes? Well, since O means no poly peptide, hither is how they intermission down into four blood types, or phenotypes:
So AO is A blood blazon because it only makes the A protein version. Aforementioned thing with BO except it is blood type B because it only makes the B version. The O contributes nothing. Except, maybe, in the adjacent generation.
How to Figure Out a Kid'south Possible Claret Blazon
Ok so now nosotros have everything nosotros need to predict what blood blazon a kid will probable have given 2 parents. All we need to know are the parents' claret genotypes.
Using a Punnett square is a groovy way to figure out a child's possible claret types based on the parents' blood types. A Punnett square is just a diagram that helps to organize all of the genes to effigy out the likelihood for a certain combination of genes.
Beginning, put the two ABO cistron versions from 1 parent along the top like this:
Hither nosotros made dad AA, which is his genotype, or his two gene versions together. He could likewise be AO and still have an A blood type, similar we saw higher up.
To keep track of things, the A blood blazon will be shaded blue.
Then, permit's say Mom is AA likewise. Nosotros put her genotype in these two squares (marked with the arrow).
If both parents are AA blood type, then that's a rather elementary Punnett square and the child can simply have the same blood type as mom and dad. Permit's work through the Punnett square to run into how.
For this to work, recollect that nosotros only get one copy of a gene from mom and one from dad. Then, for example, dad volition pass either his kickoff A or his second A but not both. While this isn't very important in this example, because the two genes are the same version, yous'll see how it is in later examples!
So let'due south do box 1 first. Higher up box 1 is dad's first A and to the left is mom's first A. We combine them to go the first possible combination.
If you continue doing the same in boxes two-4, you get this finished full-blooded.
As yous can see by all of the blueish boxes, the kid's only possible blood blazon combination is AA, just like the parents. So 100% of their kids volition be AA.
Now let'south see what we get with ii AO parents. Just similar before, we are starting with two parents with A blood type.
Only now, the Punnett square looks different!
Even though both parents however have blood type A, Dad tin pass on either his A or his O gene version. Mom can besides either pass on her A or her O.
Because of this, you lot can see that there's 1 in iv or 25% risk for a child to have OO, or claret type O.
How did I get a 1 in 4 chance? Let me prove you!
The kid tin can accept 4 possible genotypes that I've shaded hither in gray so you tin see what I'grand talking near.
Yep, AO is in that location twice, but they however count equally separate possibilities.
Out of those 4, three combinations give blood type A, I've shaded those in lighter blue below.
One combination, OO, gives blood type O.
And then at that place's a ane out of 4, or 25% take a chance, that the child will have blood blazon O and 3 out of 4, or 75% chance that the child will have blood type A.
This example shows the importance of knowing the parents' genotypes to effigy out a child'south possible blood blazon. Just knowing "type A" isn't enough information. You need to know the genotype, either AA or AO.
Let'south endeavor one more than!
What if the parents were AB and O blood type? You can start by placing the genotypes of the two parents in the correct squares.
Here the AB claret type is shown in purple.
Now we combine the blood blazon letters similar we did before.
At present, you lot tin run across a situation where the child'southward possible blood type combos are dissimilar either of the parents. The child of an AB dad and a OO mom could either be AO (blood blazon A) or BO (blood type B).
You could do a Punnett square for every possible combination of parent blood types. Or, y'all could look at this previous question and scroll to the chart at the bottom.
Hopefully you can see how information technology's near impossible to say that in general, children have the same claret type as one of the parents! But using genetics knowledge and Punnett squares, we can figure out the possibilities for a child'due south blood type based on the parents' blood types.
By Danielle Dondanville, Stanford University
If Both Parents Have the Same Blood Type Will the Baby
Source: https://genetics.thetech.org/ask-a-geneticist/parent-children-different-blood-type