The original cat: the black mackerel tabby

Melicoon Cattery

Chatterie Mélicoon

Maine Coon Cats Genotype

Aa BB Dd ll Oo Ww Ss Ii Mcmc

Upper case: Dominant gene

Lower case: Recessive gene

A	agouti	a	non agouti (solid)
B	black	b	chocolate *
D	dense	d	dilute
I	melanin inhibitor (silver & smoke)	i	non inhibited
L	short hair *	l	long hair
Mc	mackerel tabby	mc	blotched or classic tabby
O	orange	o	non orange
S	white spotting	s	no white
W	dominant white	w	non white

* Not applicable to Maine Coon

Note:

If a cat is dominant white, WW ou Ww, it will be masking any genes showing colour ie B and O and genes showing pattern ie Mc, mc, I et S

Examples:

A brown blotched tabby male will have the following genotype:

AA BB DD ll XoY ww ss ii mcmc

Aa Dd

A blue mackerel torbie female with white will have the following genotype:

AA BB dd ll XOXo ww SS ii McMc

Aa Ss Mcmc

Lastly, a black smoke tortie female:

aa BB DD ll XOXo ww ss II McMc

Dd Ii Mcmc

mcmc

Introduction

The original cat: the black mackerel tabby

The cat started its life as a wild feline available only in one model. This may be why the three principal genes in action here are all dominant:

Black is B
Mackerel is Mc
Tabby is A

Then the mutations occurred and gave life to cats which are chocolate (b) or cinnamon (bl), blotched (mc) or solid (a).

Of course, being recessive traits, for a cat to be blotched for example, it needs to inherits the mc gene from both its parents:

In this case, the dad is a mackerel carrying blotched (which he must have received from one of his parents) and mum is a blotched tabby.

Chapter 1

If you look at a black mackerel tabby, its genetic make-up could be any of the following:

BB McMc AA

BB McMc Aa

BB Mcmc AA

BB Mcmc Aa

Bb McMc AA

Bb McMc Aa

Bb Mcmc AA

Bb Mcmc Aa

Bbl McMc AA

Bbl McMc Aa

Bbl Mcmc AA

Bbl Mcmc Aa

3 x 2 x 2 = 12

There are at least two gene combinations possible for each characteristic for a dominant trait as opposed to only one for a recessive trait.

ie a black cat can have the genes BB, Bb or Bbl.

A mackerel cat will either be homozygous McMc or heterozygous Mcmc.

A tabby cat will have the genes AA or Aa.

 homozygous: when a pair of genes is composed of the same genes, ie BB or McMc or aa.

 heterozygous: when a pair of genes is composed of two different genes, ie Bb, Mcmc or Aa.

Our black mackerel tabby cat can be any of 12 genes combinations!

We can narrow it down by looking at its parents. Let’s assume we know who sired this cat: its dad is a black mackerel tabby, its mum a solid chocolate.

Dad once again has 12 possible genotypes.

Mum is showing recessive traits, so that narrows the field down:

bb ?? aa

There we hit a snag. The solid (aa) genes hide the tabby pattern. Mum could be McMc, Mcmc or even mcmc.

What do we know?

Our black mackerel tabby cat has a mother chocolate solid (also called self). So it has to get those genes from her: b and a.

It is showing all dominant genes however, so has to get those from its dad: B and A.

Our cat is also mackerel. Its dad is mackerel. Did it get its mackerel (Mc) gene from him?

Not necessarily. Mum’s pattern genes are unknown, masked by her solid genotype. Our cat could have received a blotched gene from its dad if dad was Mcmc and a mackerel gene from its mum if she was either McMc or Mcmc.

Our cat could also be homozygous fro the mackerel gene, meaning it got it from BOTH its parents:

Dad	Mum
McMc	McMc
Or Mcmc	Mcmc

Our cat genotype so far has been narrowed down to:

Bb McMc Aa

Bb Mcmc Aa

from 12 possibilities to 2!

Let’s assume once again that we know whom our mum’s parents are: both are chocolate blotched tabbies, or:

bb mcmc Aa

this we know from their daughter, our chocolate solid, as she would have needed both parents to pass on the recessive solid gene.

this we know from their colour

this we know from their pattern

Since our mum can only have been given the blotched gene from her parents, her genotype is now:

bb mcmc aa

Our black mackerel tabby cat can now only be:

Bb Mcmc Aa

The riddle is solved!

When you mate two cats together, it helps to look at their ancestors to predict what the outcome will be. But not only!

You will more often need to look also at their siblings and even at their offsprings to narrow down the possibilities.

Of course, Maine Coons can only be BB as both mutations chocolate and cinnamon are forbidden in the breed’s standard.

Chapter 2

Also on the cat evolution agenda is the orange cat or our dear red tabby.

This mutation produced a dominant gene (O) as well as linking that gene to sex: the O gene is only present on the X chromosome.

As we all know, as in humans and most animals on earth, females have two X chromosomes, males have a X chromosome and a Y chromosome. (I won’t get into the exceptions to this rule as yet.)

If our dad was a red cat, his chromosomes would carry the following “orange” genes:

XO Yo

O orange (dominant)

o non orange (recessive).

Since our tortie girl has one X chromosome carrying the orange gene, she will exhibit both colours in a patchwork.

Now, let’s change that to:

XOXo

XOY

XoXo

XoY

Unlike his sister, our red boy will be entirely red, as there is no second X chromosome to introduce the “non orange” gene.

In the same ink, it will take two XO chromosomes / genes combinations for a girl to be a red.

For this, she will need to have either a red dad & a red mum, or a red dad & a tortie mum.

Question: If you want to breed two cats together to produce a red boy, what colour will the parents need to be?

Answer: the dad: any colour, as the genes he will pass on to his sons will be located in the Y chromosome, where there is no orange gene.

the mum: now you have it! if our boy is going to be red, it will come from the X chromosome passed on to him by his mum. She will need to either be a tortie or a red.

A tortie will produce 50% of red boys.

A red will produce 100% of red boys as both her X chromosomes will carry the orange genes.

Chapter 3

To be continued...

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