one genetics question

[shamee01]

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laboratory mice are to be classified based o genes A, B AND C how many genetically distinct offspring can be produced from a ross of an AaBbCc individual with an AaBBCc individual?

i'm thinking 18, but the answer is 32 THANKS

 

[Ex_EE]

I would suggest you write them all out the long way and you will indeed see there are 32. Here is one way to look at it:
If it were just a double cross of
BbCc x BBCc
then there would be 8 different genetic combinations
BBCC
BBCc
BBcC
BBcc
bBCC
bBCc
bBcC
bBcc
Now you include the Aa x Aa and that means you multiply the 8 by 4
AA
Aa
aA
aa
because for each of the pairs above all of the B and C combinations apply.
Hope this makes sense.
I know that there is a formula way of explaining it, but I think that by working it the long way you understand it better.

 

[Danny289]

Just think this way may help you:

we have 2^3 gamets in first sequance and
we have 2^2 gamets in second one( because B is same we do not consider that one)
8*4=32
hopefully it was helpfull

 

[saaz55]

Just think this way may help you:

we have 2^3 gamets in first sequance and
we have 2^2 gamets in second one( because B is same we do not consider that one)
8*4=32
hopefully it was helpfull

one way i like to envision this is to write all the possible combos for the first parent horizontally, similar to a punnett square and the write the second parent's combinations vertically. then i count the number of combos horizontally and times it by the number of combos that run vertically (i.e. 8 horizontally x 4 vertically = 32 possible genotypes). plus this helps when they ask you a question like what is the chance that offspring will have brown hair and brown and will be tall, since u can write down all the possible phenotypes below each column. its kind of hard to describe it but if u dont understand ill draw it out.

 

[shamee01]

BBCc
BBcC
BBcc
bBCC
bBCc
bBcC
bBcc

but what's the difference between BBCc and BBcC? are they just the same？
also bBCc and bBcC

THANKS!