Genetics in Warriors by Eggsnake

Eggsnake attempts to make sense of Warriors’s genetics.

There have been many articles on BlogClan describing what Warrior cats would look like if they had accurate genetics. This is not one of those articles. Reading the books, it’s become obvious to me that the animals in the Warriors series are not real-life cats, and to achieve true accuracy, it does not make sense to apply real-life cat genetics to these fictional cats. So, in this article, I will be examining genetics in the context of cats in the Warriors world, and determine the inheritance pattern of different traits, with the help of pedigrees!

Please note that this article is mostly a joke and is just biology practice for me since we’re doing pedigrees right now 🙂 If you don’t know much about inheritance patterns yet, I would learn about them a little before reading this article! (otherwise nothing will make sense haha)

Chart 1: Firestar’s family

Firestar has probably the biggest and most important family tree out of any character in the Warriors series, so I thought it made sense to start with him. Due to the scale of Firestar’s family tree, the pedigrees may not be perfectly accurate, so please be aware of this. Very minor characters who do not have confirmed appearances and/or genders do not appear on the family tree. Also note that for each pedigree, generation 1 will always be Crystal (Firestar’s grandmother), and Firestar himself will always be in the third generation. One more thing: since there are some… questionable mate situations within Firestar’s family tree, cats who appear more than once are denoted with an asterisk.

Presence of ginger

The pedigree below follows the trait of the presence of ginger within Firestar’s family tree. For simplicity’s sake, a cat is only considered to have a ginger phenotype if they express that trait in any form. Brown, yellow/gold, and other colors that would be considered variants of ginger in real-life cats are not counted as ginger in this pedigree. Dark ginger and pale ginger are counted since they can be interpreted as different amounts of expression of the ginger phenotype. Cats described as “flame-colored”, plain orange, or anything similar are considered ginger. Tortoiseshell that is not specifically stated to contain ginger is not considered ginger.

As you can see, the ginger phenotype appears quite sporadically. We can immediately say that the gene is not autosomal recessive, as two affected parents are able to produce unaffected offspring (see Firestar and Sandstorm). The chance of the gene being sex-linked is slim, as the ratio of affected males to affected females is only 7:9; even if we assume the trait is sex-linked dominant due to the trait being slightly skewed toward females, the assumption breaks down when we look at Firestar and Sandstorm’s offspring (since Firestar is affected, all his daughters should be too, but Leafpool does not express the trait). We can try some genotypes to see if they would work, and I’ll be going through this generation by generation.

My first guess is autosomal dominant since all affected parents have affected offspring, and unaffected parents are able to have affected offspring. We don’t know Crystal’s mate’s phenotype, but if the gene is autosomal dominant, then we know that she must be heterozygous for ginger since she has unaffected offspring. This would make Jake heterozygous for the trait as well. All unaffected cats must be homozygous recessive, which matches up with what we see. Jake and Quince having no affected offspring has a fairly good chance of happening (each offspring having a 50% chance of having the trait), and Jake and Nutmeg’s offspring perfectly align with the chances displayed on a Punnett square (half of the offspring are affected and half are unaffected).

Firestar must be heterozygous for the trait because his mother does not express it. Sandstorm must also be heterozygous, as the two have unaffected offspring. Crowfeather and Leafpool, neither of whom express the trait, have no affected offspring either, which makes sense because both of them must be homozygous recessive. Squirrelstar must be heterozygous since Juniperkit is unaffected, and this means all of her affected offspring must be heterozygous as well. The expression of the trait within her offspring is quite realistic in terms of probability, so it remains very likely that the ginger phenotype is autosomal dominant.
On the other side of the tree, Princess and Oliver only have one notable kitten, Cloudtail, who is unaffected, which makes sense because neither of his parents are affected. Brightheart must be heterozygous ginger since they have unaffected offspring.

Sparkpelt and Larksong’s kittens align with the inheritance pattern guidelines and the Punnett square probabilities. All of Lionblaze and Cinderheart’s kittens are unaffected since they are both homozygous recessive. The same is true for Birchfall and Whitewing, and Snowbush and Lilyheart.

Dewnose and Sorrelstripe, both being unaffected, also have no affected kittens, which should make sense by now. Stemleaf must be heterozygous, and the probabilities are believable for their kittens. Fernsong and Ivypool, neither being affected, have no affected kittens. And now, Tigerstar and Dovewing, who are both unaffected… have one affected kitten. Oh dear.

Rowankit could technically still exist if a mutation occurred, but the chances of a mutation happening is very slim, especially if the actual DNA that controls fur color is very complex. But hey, this is Warriors, so anything goes, right? For all we know, orange fur could be one codon away from brown fur. Furthermore, Rowankit died of greencough at a young age, so a mutation in fur color may also point to a mutation in a gene that controls the immune system. Since we don’t have any other choice, we can only say that Rowankit is an anomaly and the trait is autosomal dominant. (I’ll speak more about Rowankit and other anomalies at the end of the article.)

Tabby markings

Generally, tabby markings tend to overlap with ginger quite a bit, but this time tabby cats of other colors may be included as well. A cat is only considered to have the tabby phenotype if they are explicitly mentioned to be tabby or have stripes of any kind anywhere on their body. Special types of tabbies like spotted tabbies or bengal tabbies are counted if they are explicitly stated to be tabby; a cat simply described as having spots all over their body, for instance, would not be considered tabby even though this description fits that of a spotted tabby cat.

Just looking at the pedigree I would say that the gene is not sex-linked, as it appears to affect males and females equally (with a ratio of 13:12). Two affected parents are able to have unaffected children (see Fernsong and Ivypool), so the gene can’t be autosomal recessive. That leaves autosomal dominant, and now we can start assigning genotypes to each cat to see if this works.

All unaffected cats must be homozygous recessive. Since both Firestar and Princess have the tabby phenotype, either of their parents (Jake and Nutmeg) are likely to be homozygous dominant (they can’t both be homozygous dominant since one of Firestar’s daughters is unaffected, and this would be unable to happen if he was homozygous dominant). Since none of Jake’s offspring with Quince are affected, I’m going to guess he is heterozygous and Nutmeg is homozygous dominant.

Scourge, Socks, and Ruby are all homozygous recessive, which is a little unlikely (each having a 50% chance of displaying the trait), but it still works. Firestar is definitely heterozygous as is Sandstorm, and Princess must be heterozygous as well since Cloudtail does not display the trait. This has a fairly good chance of happening.

Leafpool must be heterozygous due to having unaffected offspring, and Squirrelstar must be homozygous recessive. If Firestar and Sandstorm are both heterozygous, this follows the Punnett square probabilities fairly well. Cloudtail is obviously homozygous recessive, and we can’t say anything else about him since he has no notable siblings.

Brambleclaw must be heterozygous since he has unaffected offspring. According to the Punnett square probabilities, around half of Brambleclaw and Squirrelstar’s offspring should be affected and half unaffected, and their actual offspring match up fairly well. The same exact situation happens with Crowfeather and Leafpool’s family tree, with the probabilities still matching up fairly well.

Since all the affected offspring in the three’s generation have one unaffected parent, they must all be heterozygous. Meanwhile, in Cloudtail and Brightheart’s family tree, none of their offspring are affected, which makes sense because they are all homozygous recessive.

Sparkpelt and Larksong do not have any affected offspring, which is a little unlikely, but it works. Cinderheart must be heterozygous, and two out of six (⅓) of her and Lionblaze’s offspring are unaffected. According to the Punnett square, this would ideally be ¼, but the probabilities still align pretty well. Birchfall and Whitewing have one affected offspring despite both supposedly being homozygous recessive, but as stated before, I’m being pretty lenient on occurrences like these. If an anomaly like this happens again within the family tree, I’ll declare the pedigree to be impossible and move on. Snowbush and Lilyheart, both homozygous recessive, don’t have any affected offspring, so at least we’re good there.

Now, unfortunately, we see that Dewnose and Sorrelstripe have an affected offspring despite both being heterozygous recessive. This means that the family tree is likely impossible, or this gene is more complex than originally anticipated (see the end of the article). Oh, well. The rest of the pedigree seems to work just fine, but this generation looks a little messed up. So, I’ll say that the tabby gene is most likely autosomal dominant, or is not controlled by one simple gene.

Chart 2: Tigerclaw’s Family

As what is probably the second-most important and influential bloodline in the Warriors series, second to only Firestar’s, Tigerclaw’s bloodline definitely deserves to be analyzed just as well. Note that, since Tigerclaw has a pretty large family tree, all generations above Oakstar have been cut off, meaning Oakstar and Sweetbriar will always be generation 1. All the same disclaimers about Firestar’s family tree apply to Tigerclaw’s, so keep them in mind.

Tigerclaw look-alike

This trait sounds too specific to be real, but some real traits in cats such as the silver inhibitor override other traits completely, which makes their strangely specific effects more prevalent. If this pedigree ends up working, we can say that the Tigerclaw-clone gene is an inhibitor and overrides other pelt colors. Any cat who is described either directly as looking like Tigerclaw or is described as a brown tabby (or a dark brown tabby) is considered to carry the phenotype. As long as the cat is predominantly a brown tabby, they are considered to have this trait, so cats like Hawkfrost who have other colors in their pelts are still included. Light-brown tabbies are not considered to have the trait unless they are specified to look like Tigerclaw.

Right away we see that this trait is heavily skewed toward males, with a ratio of 6:1. Seeing as this gene can appear in offspring whose parents both do not have the gene, this gene could very likely be sex-linked recessive. Generation by generation, we can go through the genotypes to see if this could work.

Tigerclaw appears to be the first individual in the pedigree to carry the trait. As males cannot be heterozygous, and we are assuming this gene is recessive, he must have one recessive X allele, which is notated as XaY. His mates, Goldenflower and Sasha, do not display the trait, so they can be either carriers (XAXa) or homozygous dominant (XAXA). His sisters Nightkit and Mistkit do not display the trait, so they have the same two options. This means that either the gene in Tigerclaw was a mutation, or Leopardfoot was a carrier for the trait.

Hawkfrost is the only one of his litter to have the trait. Because he has it, Sasha must be a carrier for the gene. Tadpole received Sasha’s dominant allele, so he does not display the trait, and Mothwing is a carrier because she received a recessive allele from Tigerstar. The chances of this happening are fair; according to the Punnett square, half the male offspring should display the trait as should half the female offspring (and the other half should not), and that is kind of what we are seeing here. As for Goldenflower’s offspring, since Brambleclaw is affected, she should be a carrier as well. Since they only had two kittens, we can’t say much about the probabilities.

Tawnypelt has affected offspring, so she must be a carrier. This makes sense because her father displays the trait. Rowanclaw is homozygous dominant, so none of his daughters should be affected, and this is what we see. Brambleclaw and Squirrelstar have one affected offspring, meaning Squirrelstar must be a carrier for the trait. All their daughters must be carriers, and Alderheart must be homozygous dominant.

Dawnpelt and Crowfrost have affected offspring, so Dawnpelt must have inherited a recessive allele from her mother. Tigerstar and Dovewing have one affected daughter, so Dovewing must be a carrier. The chances of none of their sons displaying the trait is slim, but possible. Neither Larksong nor Sparkpelt display the trait, so it’s not too improbable that none of their offspring are affected despite Sparkpelt being a carrier.

Since there are no errors in the pedigree, we can say that the Tigerstar clone gene is sex-linked recessive. Yippee.

Amber eyes

Since eye color was not taken into consideration in the previous trait, and Tigerclaw’s amber eyes are so crucial to his look, I believe this should be a separate category. We will examine the inheritance pattern of amber eyes, and in addition, see if there is a high comorbidity with the previous trait. Any cat explicitly described to have amber eyes is included, with no consideration of other things such as pelt color. Orange or yellow eyes, or other shades of orange, are not included. Dark amber and light amber are included.

Similar to the previous trait, this trait seems to be skewed toward males, with a ratio of 8:4. This means that the trait could be sex-linked recessive, which we will check generation by generation.

Oakstar must be homozygous recessive, and Sweetbriar could be either homozygous dominant or heterozygous. Pinestar must be homozygous dominant, so Leopardfoot must be a carrier in order for Tigerstar to be affected.

For Mothwing to be homozygous recessive, Sasha must be a carrier. This means Tadpole and Hawkfrost each have a 50% chance of having the trait, and neither displays it. These chances are still fair, however. Goldenflower must also be a carrier for Brambleclaw to be affected. Tawnypelt must also be a carrier, which means she would have gotten a dominant allele from Goldenflower, which makes sense.

Because Rowanclaw is homozygous recessive and Tawnypelt is a carrier, Dawnpelt must be a carrier for the trait as well. This means the chance of all of her offspring with Crowfrost not having the trait is relatively slim, but it’s still possible. Squirrelstar must be a carrier in order for Alderheart to be affected, and Brambleclaw being homozygous recessive means all their daughters are carriers.

Dovewing must be a carrier for some of their offspring to be affected. Sparkpelt is a carrier and Larksong is homozygous dominant, so having an affected son is fine given the rules of this inheritance pattern, but having an affected daughter is not. This means that, unless something weird is happening with Finchlight, this inheritance pattern would not work. That’s completely fine, it just means we now need to check if autosomal recessive works instead.

Oakstar must be homozygous recessive, and Sweetbriar would most likely be homozygous dominant, though she could also be heterozygous. Both Pinestar and Leopardfoot must be carriers in order for two unaffected parents to have affected offspring. This means Nightkit and Mistkit would most likely be heterozygous, but we can’t say for sure.

Sasha must be a carrier for the same reason, as should Goldenflower, and all of the Punnett square chances are looking pretty good so far. Tawnypelt and Squirrelstar should both be carriers. In the case of Brambleclaw and Squirrelstar, since the former is homozygous recessive and the latter is a carrier, half of their offspring should be affected and half unaffected; this isn’t what we see, but it’s fine, because these are chances, not predictions.

Crowfrost and Dawnpelt don’t have any affected offspring. Dawnpelt must be a carrier since her father is affected, so Crowfrost is most likely homozygous dominant. Dovewing must be a carrier, and Tigerstar must be homozygous recessive, and around half of their offspring are affected, which perfectly aligns with the Punnett square. Larksong and Sparkpelt are both unaffected but have affected offspring, which means both must be carriers.

There are no errors in the pedigree using autosomal recessive, which means that is most likely the inheritance pattern for this trait. As for comorbidity with the Tigerstar clone trait, there is some, but definitely not enough to warrant any theories. I definitely expected it to be much higher.

Conclusion

Based on the pedigrees analyzed in this article: within the fictional world of Warriors, the ginger pelt color in cats is autosomal dominant; the tabby pattern is autosomal dominant; the dark brown tabby pattern is sex-linked recessive; and amber eyes are autosomal recessive.

Addressing anomalies

Now is the part where I talk about the outlier kittens who don’t follow the inheritance pattern of the rest of the pedigrees. This article boils down genetics into a very simplified version of the real science, and genetics in real life is actually very messy. There are lots of mutations, strange shenanigans, gene minglings, and other weird things that can happen. In real life cat genetics, for example, the tabby pattern is controlled by a number of genes that interfere with each other and mix in a way that can be pretty unpredictable, even with all the Punnett square calculations. Even with simple things, like the base pelt color which follows simple dominance, weird genes like the silver inhibitor or the white pelt gene can override other genes and make surprise kittens that don’t look like their parents at all. This can explain a lot of the strange phenomena that might occur with pedigrees, and it could be behind the mystery kittens in these fictional pedigrees.

Final words

This article was written for fun, but also took me several months because I kept forgetting about it and now the pedigree unit in biology is completely over and was actually from last semester. Oops. I originally wanted this article to be a lot longer, but honestly I’ve already said way more than anyone wants to hear about genetics in a fictional cat world. I hope you got something out of it, at the very least.