Gerbil Genetics 101: A Basic Introduction

Welcome to the world of gerbil colour genetics – and I wish you a happy journey.

Genetics is often talked about in the gerbil world – and it can seem very daunting at first – but I want to make it simpler for you.

Here is just a nice broad overview introducing and exploring the very basics of the topic so you can then move on to something a little more detailed in time – but with an idea of what it is all about.

The way gerbil genes work in the sense you need to know right now is so simple – you will wonder what all the fuss is about.

Gerbil Genetics is just one simple concept:
Basically it boils down to a single pair of letters and what they look like written down.

As with all written letters used in English – they are either BIG (uppercase or capital letters) or they are small (lowercase letters).

All gerbil genes in use today are given a letter (or letters) based loosely on ‘what they do’ so if we use the gene that makes a gerbil an Agouti or not – we shall call it the ‘A’ gene = A for Agouti.

The Agouti Gene (A):
A capital ‘A’ is used to represent the version of that gene that makes your gerbil look like an Agouti. It is big to show you that it is important – what in the genetics world is called ‘dominant’. It usually works alone.

A lowercase ‘a’ is used to represent the version of that gene that doesn’t make your gerbil look like an Agouti – it’s what makes it look different. It is shown small to show you that it is less significant than the dominant version and it is called ‘recessive’. It usually works in pairs.

And finally – all gerbils can only have 2 of these genes in their body at any one time – but in any combination.

In this example with just a big A and a small a, that leaves us with just 3 possible combinations:

A and an A – AA
A and an a – Aa
a and an a – aa

You won’t find a gerbil with AAa, aaaa, aAaAa or AaAaAaAa.

They can only have one single pair of genes at this point as there is only space for two genes at this point. Always two.

But What Do These Combinations Mean?
The way these colour genes are written down is the key to understanding gerbil colours and how to create them. I won’t go into any details about why they create the different colours and how they do it – that is a whole other topic.

All you need to know is how these two genes work together.

AA – if you have two capital letters, it means that your gerbil is the colour that the gene represents – the dominant colour. So a gerbil with two dominant genes versions that represent ‘being Agouti’ means that the gerbil is going to look like an Agouti.

Aa – if you have two different versions of this letter – but one of them is a dominant gene – that is the colour that you will see. The big dominant A here works a treat and makes this gerbil look like an Agouti. The small a is still there working behind the scenes, but you can’t see its effect because it isn’t strong enough to outshine the dominant version.

aa – if you have two versions of the recessive gene together – they can finally work. You will see a new colour – and it won’t be Agouti. You don’t have a dominant version of the Agouti gene covering up their action with its agoutiness. These individuals are not and will never be Agouti coloured.

Still with me?

Well, once you have grasped that simple concept, you can apply it to all the other gerbil colour genes in the same way.

Even though you are always thinking of each gene individually, these effects can add up to create new colours – but they follow an easy pattern genetically.

You just add together the gene combinations for the different letters. You never mix up the letters – you just place them side-by-side.

NB: The actions of these genes within the body are quite complicated, but basically they tell the gerbils hair follicles to do different things. Each different colour gene changes the instructions the hairs are given when they are growing and so change the colours of the coats they create.

The Pink Eye Gene (p):
If you had your Agouti-coloured gerbil (AA) and you added two recessive ‘pink eye’ genes to it (pp) – you would get a Pink-Eyed Agouti:

AA + pp = Argente Golden (genetically a Pink-Eyed Agouti)

Then if you took your non-agouti gerbil – the Black gerbil – and added two recessive pink eye genes to it (pp) – you would get a Pink-Eyed Black:

aa + pp = Lilac (genetically a Pink-Eyed Black)

The Extension of Yellow Gene (e):
If you had your Agouti and Black gerbils and added two recessive ‘extension of yellow’ genes to them (ee) – you would get the following colours:

AA + ee = Dark Eyed Honey – aka – DEH (an ee Agouti gerbil)
aa + ee = Nutmeg (an ee Black gerbil)

Add all three together and you get even more colours where the effects of the genes interact in their own unique way:

AA + ee + pp = Red-Eyed Honey – aka REH
aa + ee + pp = a Saffron

Have you noticed these colours all come in pairs? One colour on the Agouti ‘side’ if you like and one on the non-agouti side.

It is easy to work out the colours when you think of them as on one of these two sides. It helps to distinguish between the colours based on their appearances. More of that in other articles…

But what happens if the recessive genes aren’t there?
If your Agouti doesn’t have two recessive genes at the Extension of Yellow point – it won’t show them. It can’t show them. It will just stay looking like an Agouti.

Same at all the other points – if your Agouti doesn’t have two recessive Pink Eye genes – it can’t have pink eyes; and if it doesn’t have two recessive non-agouti genes – it can’t be non agouti.

Whatever genes it doesn’t have – it can’t show of course – and this is why most gerbils ARE Agouti. There is a much greater chance that it won’t have two of all these recessive genes than there is of it having them.

So, what about all the other genes?
You’re a bit keen here – and I like that – but hold your horses.

There are plenty of other genes that you will hear about like the colourpoint genes, Schimmel genes and spotting genes – but don’t worry about those for now, they can be a little more difficult to work out.

Get to grips with how the basic gene pairs work for all the simplest colours first – they follow the same rules and are really simple to work out.

The rules are the same for these more difficult genes – the fact you can only have two of them at any one point is the main one – but there are a few twists and turns along the way that can cause confusion.

Too complicated to explain here in this 101 Basics.  

NB: This simplified article is only referring to coat colours – not any genetic effects in addition to this (like with the spotting genes or rex coats etc).

These genes have different effects on the body of the gerbil outside of just changing the colours of the individual hairs and irises and so work in slightly different ways to the above descriptions.