Whitmoregirl's Wombles

Welcome to the first eTard help guide!

Today we will be covering gerbil genetics & introducing Professor Gerbil – he doesn’t have anything to say today, he’ll just be watching you to ensure you’re paying attention. He likes to study eTards.

We will use this backpack and pretend it is a gerbil.

As you can see, we have left it blank. There are no genetics there so don’t get ahead of yourselves or else safety helmets will be issued. Please note that all metaphorical genetics for backpacks here are fake.

Genetics are on (hold onto your helmets for big words in bold!) CHROMOSONES.

If you look very very very very closely at your skin you will see very very very very tiny cells. In those very very very very tiny cells are even tinier things! A lot like filling the above backpack with lots and lots of sand!

Chromosones are in the nucleus (or brain) of each cell and tell the cell how to behave – how to form etc. They also store the genes that will be passed down to offspring. Gerbils have 44 chromosones.

These genes will also tell the body how to form, so if you have a backpack with a large buckle or long, bristling whiskers, this will be inherited by the babies.

Now pretend a breeding pair of backpacks are both like this!

Both of the parent bags are RR (red). Red is a dominant, which is why it is written in capitals. Because both ALLELES (the two letters, R & R) are the same, this is called HOMOZYGOUS.

When they breed, the baby bag will also be RR!

However, what happens if one backpack parent is white (ww) and the other red (RR)?

In gerbils, recessives can affect the overall colour of the gerbil. So, if a backpack has a similar style of genetics, the baby bag will be Rw, and possibly look like this, a pinky colour (colours may vary please note this is an exaggerated example).

Because the two ALLELES are different, this is called HETEROZYGOUS.

White is recessive, which is why it is written in lower case. Dominant genes come before recessive, for example Rw. You do not put wR as the white is not visibly showing.

In other species, recessive genes will rarely show on the outside (the skin, fur or materials), so a Rw car would be still red. You would have to go into a cell on the car and look at the chromosones to find out it is carrying white, or else breed it with a known white (ww) car. This has an equal chance of producing red or white offspring.

You can see this on a simple punnett square. The parents’ genes are on the outside. We put one gene in each box because each sperm will carry only one out of the two alleles, which will pair up with the egg’s single gene to form a complete CHROMOSONE.

You can also think of dominant traits as a large, open bottle of vimto or cranberry juice (or any other colour) being placed in the backpack. This will spill and colour the outside of the bag.

Recessive traits are like smaller, half open bottles of drink, which will only minorly affect the outside unless in pairs, and will be barely visible against the staining of a dominant bottle.

You will also get some genes that can only be carried down to the offspring if one or both of the parents visibly have it, for example one of the spotting types we have in gerbils called DOMINANT SPOT. One or both parents must have it (even if it is only visible by a few hairs) for it to be passed on, as it cannot be carried RECESSIVELY.

One thing that non-spotted gerbils can carry are MODIFIERS which if crossed onto a spotted offspring, will alter how the spotting forms.

So if we take a white, spotted backpack and cross it to a white, unspotted backpack, you potentially have a 50:50 chance of the offspring being born with spotting!

However it is not guaranteed that even with two spotted parents, the produced offspring will be spotted as it is down to chance (and which sperm is the toughest).

If you still cannot understand this dumbed-down version of genetics, a special edition of the eTard’s guide to pet rocks will be coming your way soon!