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An orange tabby Scottish Straight cat sits on a shelf in a veterinarian's office

The Scottish Straight is required to create healthy Scottish Fold cats. Photo by JaneA Kelley

I never imagined I’d be the mama to a purebred cat.

I never intended to. I’m Team Adopt Don’t Shop all day. But when a friend needed to rehome his Scottish Straight cat, I said yes. He was a cat that needed a home, and that trumped everything else. That’s him in the photo at the top of this post. His name is Wallace, and he’s settling in quite well. Bella and Tara are still hissing at him sometimes, but things are improving with each day.

Meeting Wallace got me thinking about the Scottish Fold. Why? First of all, the genetics intrigue me, and if you’re as nerdy as I am, you’ll think this is cool, too.

Scottish Straight and Scottish Fold genetics: a primer

The gene that causes the folded ears is an autosomal dominant gene. A gene is composed of two alleles, one inherited from each parent. In the case of the Scottish Straight-Scottish Fold, the alleles are F (folded ears) and f (straight ears), meaning only one copy of the Fold gene is needed to create the Fold’s famous folded ears. Here’s a chart called a Punnett Square, which shows the possible variations when two cats with the folded-ear gene are bred together.

A Punnett square diagramming the inheritance of the folded-ears gene in the Scottish fold, when two cats with folded ears are bred together.

There are three different genotypes–FF, Ff, and ff–that can be created when two Scottish Folds are bred together. The ff genotype, which has no copies of the dominant gene that creates the folded ears, produces the Scottish Straight.

As you can see, the three genotypes mentioned in the caption produce two phenotypes (physical looks): cats with folded ears and cats without. Wallace was born to a Scottish Fold mother, but he has no copies of the folded-ears gene so he has straight ears and much better health than the typical Fold.

Health issues with the Fold gene

The gene that causes the folded ears in Scottish Fold cats also produces a host of medical problems. The reason the Fold’s ears fold is because their cartilage is too weak to hold them up straight. That weak cartilage, combined with ongoing and potentially very severe bone, ligament, and tendon problems, create a condition called osteochondrodysplasia, which, translated into everyday language, means “bone (osteo) and cartilage (chondro) cell disease (dysplasia).”

All cats with the Fold gene have some degree of osteochondrodysplasia. This means Scottish Folds will inevitably develop degenerative joint disease, which can result in fusing the bones of the tail, ankles, and knees. If a cat has two copies of the Fold gene, their symptoms will be much more severe and result in a very short but horribly painful life.

Both Scottish Folds and Scottish Straights are at an increased risk of developing hypertrophic cardiomyopathy and polycystic kidney disease. Good breeders will screen their cats for the gene that causes polycystic kidney disease. I don’t believe there is a genetic test to determine the risk of hypertrophic cardiomyopathy. If you have a Straight or a Fold, you may want to talk to your vet about things you should look out for that could be signs of either of these diseases.

To avoid breeding Folds that have two copies of the Fold gene, Scottish Folds are bred with Scottish Straights or outcrossed with breeds such as the British Shorthair and American Shorthair. What that means is that one parent has zero copies of the Fold gene, and one parent has one copy of the Fold gene, which will produce a litter of half fold-eared kittens and half straight-eared kittens.

A Punnett square depicting the results when a Scottish Fold is bred to a Scottish straight.

When a Fold is bred with a Scottish Straight, half of the kittens will be Folds (with one copy of the Fold gene) and half will be Straights.

Is the Scottish Straight a recognized breed?

The Scottish Straight is recognized by TICA, The International Cat Association, but at the time of writing this (May 2024), they had not been added to the Cat Fanciers’ Association’s list of recognized breeds. I’m told that Scottish Straights often compete in the household cat category at CFA shows and do very well because of their pleasant disposition and love of human attention of almost any kind.

Meet my Scottish Straight friend, Wallace

When a friend posted on Facebook that he needed a home for one of his cats, I responded. Although I’ve done really well at keeping myself at two cats since Thomas died in 2020, I got such a strong intuitive YES when I thought about this cat that I had to offer to adopt him. So, just over a week or so ago, I met my friend at the midpoint between my home city and his home city to pick up Tangerine, who quickly revealed himself to be a Wallace. I was pretty sure he was going to need a dental, and I figured I could save up for it.

Once he got settled in, Wallace came out of his shell and his true, delightful personality began to shine through. He is the sweetest, most delightful, most people-friendly, biggest “moosh” I have ever seen. The only problem we’ve had is with eating. When I first brought him home and watched him eat, he was showing signs of dental pain. It took me a day or two to start mixing canned food with water and blending it into a slurry. He does eat some of that, and he even eats kibble. But only one or two bites at a time, followed by furious licking at his lips and pawing at his mouth.

I took him to the veterinarian last Wednesday to make sure he didn’t have anything contagious before exposing him to Bella and Tara. I mentioned my concerns about his mouth and … yeah, he’s got some issues. His two lower canine teeth need to be removed, as well as possibly some of his upper incisors. That means the dental is much more urgent than I thought, especially because his mouth pain is making it hard to eat. I’ve set up a GoFundMe for Wallace’s dental, and I hope you’ll consider donating and/or sharing so I can get Wallace’s mouth feeling better as soon as possible!

An orange and white Scottish Fold cat with a white muzzle.

The Scottish Fold is cute and lovely, but if it weren’t for the Scottish Straight and outcrossing with British and American Shorthair cats, the Fold breed would be even more replete with suffering. Photo by Scott Greer on Unsplash