Just like human siblings, cat siblings sometimes love each other and other times wish they could stuff their little brother in a box and sit on top of it. But, have you ever wondered just how genetically similar your cat siblings are? Here is what you need to know about cat siblings genetics.

Cat siblings genetics

Cat siblings are generally genetically very different. Unless the breeding occurred in a controlled environment, kittens of the same litter can actually have different fathers. This phenomenon is called heteropaternal superfecundation, and it’s actually a lot more common that you would think!

However, even those kittens who have both of the same parents, have likely randomly inherited a number of different gene combinations. This means that while certain genetic traits will be shared by the siblings, every sibling will be genetically unique. This remains untrue only for identical twin cats.

Identical twins are cats who have developed from the same initial egg fertilized by one sperm. This happens when a fertilized egg divides early in the development and results in two different lineages of cells who will ultimately form the whole organisms. This means that the two identical cats will carry the same genetic information. Unlike human identical twins, it can be rather difficult to recognize cat twins though, because the color pattern genes can be expressed differently in two cats even when the genetic information is identical.

With that being said, unless two cats are identical twins (which cannot be determined based off appearance), the DNA test results of two cat litter-mates are expected to be different. While siblings will have a certain amount of DNA in common, the combination of all the possible genetic variants given by the parents will be unique for each individual.

How do cats inherit such diverse DNA combinations from two same parents?

If your cats share the same fur-parents, then it’s common to hear that they share “50% of their DNA.” However, it isn’t all that simple. The truth is, there are so many different combinations of DNA your cat’s can inherit from two parents.

Kittens (just like human babies) have two copies of each gene. They receive one copy of each gene from one parent. Therefore, every kitten will receive 50% of their DNA from their mom and 50% from their dad. However, it is completely random which copy of their gene a parent will pass on to the kitten.

This means that two siblings can inherit two different copies of each gene from each parent. If they inherit the same variants of a certain gene from their parents, they will be genetically more similar for this gene. But, for another gene, they might be completely different too. Therefore, two kittens can be more or less genetically similar, and it can’t be predicted to which percentage this will be.

pregnancy in cats queen mom with kitten

Queen with a kitten

Do you have more than one fur-baby at home and want to get their DNA tested? Contact us for special discount pricing!