# Punnett squares



## firstmice (Sep 18, 2013)

How do they work? Can anyone teach me how to use one please?

Thankyou.


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## PPVallhunds (Jul 26, 2010)

Ok you use punnet squairs to work out what combos can be made by breeding together to mice. It can be very easy to use it for working out one gene set at a time. so for my example we will be doing one for the A set of genes for a breeding between a Black doe and an agouti carrying non agouti buck.

So first we draw our punnet squairs as below









Then we put in the parents a set genes by putting one parents genes in the top two boxes and the other on the left two boxes like below









then in the black spaces we simply fill them in by putting the gene in from the parents from that row or coloum. like below









each of those 4 boxes we just filled in represent a possible combo so we can then add the name of the colour that combo would be.









Now we know what the possible combos are we can work out how likely we are to get each one, rember its out of 100 percent, so we have two agouti and two black so that is 50/50 split, so 50% chance of agouti and 50% chance of black. 
Now remember that is not saying that 50% of the litter will be black, its saying that each pup born has a 50% chance of being black, so depending on luck or every pup in the litter could be black, or maybe just one will be.


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## PPVallhunds (Jul 26, 2010)

so if you get that, try doing one for a doe who is red carrying black (AY/a) to a buck who is Agouti tan (A/at) and see what you come out with.


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## firstmice (Sep 18, 2013)

Thankyou Jo  
Ooo I will try and let you know what I come up with  X


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## firstmice (Sep 18, 2013)

o wow! such a headache, I'm so confused, I just don't get it,  but here is my 2 attempts! No laughing Jo :lol: :lol: :lol: :lol: x





Any idea where I'm going wrong?   x


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## PPVallhunds (Jul 26, 2010)

Dont worrie you haven't gone wrong, you have done it right,  well done!

the first one is better as in the combo boxes you put the most dominant gene first. (You just have to rember which genes are the more dominant ones)
So your combos are as you said in the first one
Red carrying agouti, Red carrying tan, Agouti carrying black and black tan.

So to get the percentages you have 2 reds, 1 agouti and 1 black tan, so 50% red, 25% agouti, 25% black tan.


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## firstmice (Sep 18, 2013)

PPVallhunds said:


> Dont worrie you haven't gone wrong, you have done it right,  well done!
> 
> the first one is better as in the combo boxes you put the most dominant gene first. (You just have to rember which genes are the more dominant ones)
> So your combos are as you said in the first one
> ...


O really!!! Woop woop, I'm ridiculously excited to have got this far :lol: 
Thanks so much for your help Jo  X


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## pauly (Feb 21, 2013)

How does this work Jo, if a mouse is split for another variety. Say, if you mated a Chocolate to a Black, some of the youngsters would be Black carrying Chocolate.


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## SarahY (Nov 6, 2008)

Well done Firstmice! Only one thing: "red carrying tan" (Ay/at) is a sable  You did the calculations right, just need to familiarise yourself with the gene codes for each variety.

Although, that said, for showing mice phenotype is everything and genetic codes don't matter!


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## firstmice (Sep 18, 2013)

SarahY said:


> Well done Firstmice! Only one thing: "red carrying tan" (Ay/at) is a sable  You did the calculations right, just need to familiarise yourself with the gene codes for each variety.
> 
> Although, that said, for showing mice phenotype is everything and genetic codes don't matter!


Thankyou Sarah  , I thought it was sable but didn't want to get it wrong :lol: , I have written down most of the codes , trying to memorise them, hmm phenotype? (What the mouse looks like? The characteristics ?)  :lol:

X


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## moustress (Sep 25, 2009)

You are doing very well. I have never understood why some people have trouble with a simple grid chart like this.


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## PPVallhunds (Jul 26, 2010)

pauly said:


> How does this work Jo, if a mouse is split for another variety. Say, if you mated a Chocolate to a Black, some of the youngsters would be Black carrying Chocolate.


You would do the punnet squaire the same but for the chocolate gene. so if the black didn't carry choc you would put B / B in the side and the chocs b / b in the top. All 4 squairs would be B/b so black carrying choc.
if the black carried choc you would put B / b in the side. So in the 4 boxes you would get black carrying choc and choc.

It gets more work when you want to work out mutable genes at once as you have more to figure out, like say a black carrying blue and albino bred to a blue Siamese. 
so you have a/a D/d C/c and a/a d/d ch/ch.
which would give 
black 25%
blue 25%
blue himi 25%
seal himi 25%


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