Back to Biology: Ragdoll Genetics

by | Jan 26, 2025 | Ragdoll Genetics

st. louis missouri blue colorpoint ragdoll

Discover the Genetics Behind Ragdoll Cat Colors

I don’t know about you, but it’s been a long time since I’ve taken a science class. So, over a year ago, when I knew my future would involve breeding ragdolls, I took it upon myself to do a bit of my own research in preparedness. 

I may not be as experienced as some of the long-time breeders in TICA, CFA, FIFE and the like, but I do my research. If I’m going to jump in feet first, I want to be prepared for anything. Education is key. And I decided I was not going to go in blindly.

This blog contains notes I wrote over the last year. Pages and pages of information, details, questions asked and answered by friends, other breeders, scientists, veterinarians, etc., so I could learn along the way and ensure I do right by my cats, their kittens, and hopefully, YOU, a future ragdoll owner!

I will never claim to know everything, in fact other breeders, doctors, science teachers, those who run shelters … please correct me if I misunderstood something and printed incorrect information here. I am doing my best, but I promise, I’m not perfect.

So, join me in exploring the fascinating world of ragdoll genetics and uncover how specific color traits are passed down through generations.

For now, let’s start with some vocabulary.

On to Vocab
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Understanding Ragdoll Genetics - Starting with Vocab

Certain sections of DNA play a crucial role in defining the color traits of ragdoll cats. Each section of DNA corresponds to a specific gene, which in turn influences a particular characteristic, such as coat color or eye shape. These genes are organized into alleles, with dominant alleles having a stronger influence on the phenotype than recessive ones. Understanding these genetic codes allows breeders to maintain the breed’s distinctive features and ensure the well-being of each Ragdoll kitten.

As mentioned earlier, to understand the genetics of ragdolls, you have go to back to high school and re-learn everything you forgot.

Here is what I gathered in my research.

GENES: Sections of DNA that code for a specific trait

GENOTYPE: DNA sequence that makes up an organism

PHENOTYPE: An observable trait influenced by genotype – the type of traits in a section of DNA

    • ie; eye color, hair color

ALLELES: Different versions of a gene, which vary at a particular genome location. An individual’s combination of alleles is known as their genotype, as mentioned above. One member of a pair of species of genes that occupy a specific position of a chromosome.

    • The specific letters that make up the phenotype
      • ie; BB, Bb, bb

DOMINANT ALLELES: Stronger genes

1. Dominant Alleles will have more of a say in what genes a species picks up than recessive alleles. You must have two recessive alleles to create an offspring displaying a recessive trait. So, I, Christy, have brown eyes, but I carry blue eyes because my mom has blue eyes. My husband, Matt, has brown eyes, but also carries blue eyes because his dad has blue eyes. We have three kids, two of which have brown eyes, but our youngest, Natalie, has blue eyes because she inherited two recessive alleles: One from me and one from Matt. We all inherit one pair of alleles from mom and one pair from dad.

        • Ragdoll cat colors are located on the B locus
          • BB = dominant | bb = recessive

DILUTE: When a kitten inherits two copies of the “d” gene (one from each parent, resulting in a dd genotype), it dilutes the color of the points, creating a Blue Ragdol

  • DD= undilute | dd = dilute

HETEROZYGOUS: Having different alleles of a gene

    • Bb or Dd

HOMOZYGOUS: Having the same alleles of a gene

    • BB or DD
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DNA: The Blueprint of Traits

Phenotypic Expressions in Ragdoll Cats

DOMINANT

The BB Allele

Seal

Seal | BB or Bb | Dominant Gene

A dominant gene only needs one copy to be visible. For example, the black (seal) gene (B) is dominant over the chocolate gene (b).

Whether they have B or Bb, they will always display the BB, being black (seal) in color. The lowercase b means they are a carrier of chocolate, meaning they have the possibility of passing chocolate down to their offspring.

RECESSIVE

The bb Allele

Chocolate, Cinnamon

Chocolate | bb | Recessive of Seal
Cinnamon | b¹b¹ | Recessive of Chocolate

A recessive gene needs two copies to be visible. For example, the chocolate gene (bb) is recessive to the black (seal) gene (BB).

Cinnamon is recessive of chocolate. That is why there is a ¹ behind the b. A Cinnamon cat (b¹b¹) is double recessive because cinnamon is recessive of chocolate and chocolate is recessive of seal.

DILUTE

The dd Allele

Blue, Lilac, Fawn, Cream

Blue | BBdd | Dilute of Seal
Lilac | bbdd | Dilute of Chocolate
Fawn | b¹b¹dd | Dilute of Cinnamon
Cream | OOdd (f) or Odd (m) | Dilute of Red

The dilute gene (dd) reduces the amount of pigment in a cat's coat, resulting in lighter colors. For example, a seal-colored Ragdoll with the dilute gene will be blue. If you see the capital D, it simply indicates that the cat is not dilute. If you see Dd, it means they aren't dilute, but they have the possibility of passing dilute down to their offspring.

SEX LINKED COLOR GENES

The O Allele on the X Chromosome

Red, Cream

Red | O | Males
Red | OO | females (not as common as male)
Tortie | Oo | Females (with rare exceptions)
Cream Males | Odd |
Cream Females | OOdd | (less common than males)
Torties with dilute | Oodd | Only Females (with rare exceptions)

The sex-linked gene (O) that determines a cat's fur color are located on the X chromosome. Red or cream Males only have one O allele because they only have one X chromosome. Whereas a female may be Red (OO) or Cream (OOdd), although it's rarer because they will usually be torties. (more on this later)