Unlike dogs, most cats do not have purebred ancestors (read our previous blog for more about the recent history of cat breeds). However, every cat shares more ancestors with some cat breeds than others. In order to serve all cats regardless of their pedigree, Basepaws developed a Breed Index that can be used by any Domestic or purebred cat.

How is the Breed Index calculated?

After Basepaws sequences your cat’s DNA, we compare your cat’s genome to other cats that have been sequenced. For all the thousands of locations along your cat’s DNA that can be similar or different in other cats, we record how many similarities your cat shares with different purebred cats. Then we use this value to determine how similar your cat’s DNA is to each breed in our database.

Cats of the same breed look similar and they generally share more DNA with each other than with other cats. However, within each cat breed, there can still exist a lot of variation (physically and genetically). If a single cat breed has a wide variety of DNA sequences, it is harder for us to predict how similar your cat is to the overall breed. The width of your cat’s Breed Index reflects the variability of each breed – the wider the Index, the less sure we are about this prediction.

How can I interpret the Breed Index?

Cat breeds that have been compared to your cat are listed in order of best match. If the marker is to the right of “Domestic”, then your cat has more DNA in common with that breed than a typical cat. If it is to the left, then it has less DNA in common with that breed. Your cat will probably have an index of “Domestic” for most of the breeds.

When your cat has more DNA in common with a breed, it indicates that your cat probably shares recent ancestors with cats of that breed (compared to an average cat). This could happen if your cat belongs to that breed, if your cat’s family tree contains that breed, or if your cat has ancestors that gave rise to that breed.

Your cat’s results could include:

Multiple matches:
Does your cat match with more than one breed? This could indicate that your cat’s parents (and/or their parents) were different breeds. Your cat will also have multiple matches when one breed is related to another. For example, if your cat is a purebred Bengal, then there is a good chance that it will also be highly related to the Egyptian Mau. This is because Egyptian Maus were originally bred with the Asian leopard cat to create the Bengal breed. Finally, the most likely reason for multiple matches could be that your cat shares many ancestors with a few different breeds.

No matches:
Not all Basepaws cats have good breed matches yet. If your cat does not match with any of these breeds, we will notify you when the next report update is available. The next reports will continue to include more breeds and your cat’s report will continue to grow and improve with time.

Unexpected matches:
Does your cat look nothing like your cat’s best match? The Breed Index measures overall DNA similarity, and genes control much more than just looks. In fact, many physical traits (like short legs, hair length and some colors) are only caused by single genes. If your cat doesn’t look like its genetic match, read a little more about the match’s personality and other traits.

This is a list of Breeds included in the current report:


American Shorthair


British Shorthair


Devon Rex

Egyptian Mau


Japanese Bobtail


Maine Coon


Oriental Shorthair







Tennessee Rex


New breeds will be added in 2019:


Bombay Cat

Exotic Shorthair


Norwegian Forest Cat

Russian Blue



Scottish Fold

Turkish Angora

If your cat is a pedigreed purebred that does not match with its breed on our report, please let us know!

*Our test cannot currently be used to register your cat as a purebred. However, if your cat has the trademark characteristics and genetics of the breed, you might refer to your cat as a “mix”.

**Disclaimer: The Basepaws Breed Index is not a breed test, and can not tell exactly what breed your cat is. Basepaws is continuing to expand and evolve our tests, and as more cats are added to our database, we will have more accuracy in all our reports. Our current results should not be used to treat or diagnose disease.