Genetics Question

[hope_to_match]

Advertisement - Members don't see this ad

Two genes, A and B are linked, so an individual who is AaBb produces equal number of 4 gametes (2x2=4)

I am having trouble calculating the number of gametes if A and B are not linked . I remember I stumbled upon this type of question in one of the practice tests (i believe it was achiever). Does the answer change? How would I calculate it? Thanks

 

[Riz0791]

I thought it was if they are linked then the individual produces two gametes AB and ab and if the two genes are not linked the individual produces 4 gametes AB Ab aB aB?

 

[hope_to_match]

I thought it was if they are linked then the individual produces two gametes AB and ab and if the two genes are not linked the individual produces 4 gametes AB Ab aB aB?

maybe i got it all confused..i need some clarification on this as well..though what you said it makes sense

 

[Jordwin]

I'm not sure on the linked vs not linked discussion, but the math on that one is 2^n, not 2 x n. In this case it worked and you got 4 anyway, but for future reference, if there were three genes it would be 2^3=8 not 2x3=6. Hope this helps.

 

[Riz0791]

From my understanding since linked genes are on the same chromosome and cannot assort independently they will produce only 2 gametes whereas the non linked will produce 4. 3rd edition of cliff's (pg 96) actually explains this topic I think it may clarify it for you

 

[hope_to_match]

I'm not sure on the linked vs not linked discussion, but the math on that one is 2^n, not 2 x n. In this case it worked and you got 4 anyway, but for future reference, if there were three genes it would be 2^3=8 not 2x3=6. Hope this helps.

yeah i know it is 2 to the power of. I just didnt write it out. But my question was how to calculate when question specifies linked or not linked.

 

[aznriptide859]

If they're not linked, then A alleles and B alleles will separate independently. You would use the 2^n formula for figuring out possible allele combinations.

If they are linked, then they will separate together, but I believe frequency of separation depends on the genotypes of the parents.