Genetics question help plz.

[pbmason]

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I am having trouble with these questions, can someone please answer and explain. Thanks.

Question 1:
How many genetically different gametes can be formed by a mouse that is genotypically AABbCc? (Assume no linkage btw these genes and that none are lethal).


Question 2:
Assuming independent assortment, what is the possible number of different gamete types from three homologous pairs?

 

[Mrbubbles]

I am having trouble with these questions, can someone please answer and explain. Thanks.

Question 1:
How many genetically different gametes can be formed by a mouse that is genotypically AABbCc? (Assume no linkage btw these genes and that none are lethal).


Question 2:
Assuming independent assortment, what is the possible number of different gamete types from three homologous pairs?

regarding question 1: gametes include one allele from a parent, so u can ABC, ABc, AbC, Abc ..so 4.
definitely understand this cuz a genetics question will be on the dat.

number 2? i dunno.

 

[firstcitizen]

regarding question 1: gametes include one allele from a parent, so u can ABC, ABc, AbC, Abc ..so 4.
definitely understand this cuz a genetics question will be on the dat.

Timing is pretty crucial and if the exam came up with a question where it was AaBBCcDdEEFfGG, you would be wasting time by writing down the combinations.

Just use 2^n (n = number of heterozygous genes)

B & C are heterozygous, therefore 2^2 = 4.

 

[Steven11224]

Answer to question 2 is 1. AAbbCC or any other homologous pair combination will produce 1 gamete

 

[pbmason]

The answer to question 2 is actually 3, but I do not know how or why. Can someone explain please?

 

[raya23]

question two states that there are 3 homologous pairs, so the answer has to be 3 since they are homologous, not hetero

 

[D.D.S.]

For Question 2, what are the alleles on the homologous chromosomes?

Just because the chromosomes are homologous, that doesnt mean they are identical.

So I think for this question we need to know what are the alleles on them for example are they: Aa, Bb, and Cc, if this is the case, I believe you will have 8 different gametes according to the law of independent assortment, and if the alleles are AA, BB and CC, then simply only one type of gamete...

 

[firstcitizen]

question two states that there are 3 homologous pairs, so the answer has to be 3 since they are homologous, not hetero

Where's the logic in that?

Homologous chromosomes does not equate to homozygous alleles at each locus.

I skimmed through this post before heading of to class this morning and I kept running it through my head and wondering why the answer is 3?

They can be heterozygous or homozygous pairs or a combination for each locus. The only information given is that they are homologous pairs and nothing else.

If it were AABBCC = 1
AaBbCc = 8
aabbcc = 1
AaBBCC = 2
AaBbCC = 4, etc.

😕😕😕

 

[D.D.S.]

Where's the logic in that?

Homologous chromosomes does not equate to homozygous alleles at each locus.

I skimmed through this post before heading of to class this morning and I kept running it through my head and wondering why the answer is 3?

They can be heterozygous or homozygous pairs or a combination for each locus. The only information given is that they are homologous pairs and nothing else.

If it were AABBCC = 1
AaBbCc = 8
aabbcc = 1
AaBBCC = 2
AaBbCC = 4, etc.

😕😕😕

Yup! I agree..