Dihybrid Cross

[inaccensa]

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Ek q- In a dihybrid cross, what fraction of the offrspings are likely to be dihybrids?
Since the ratio is 9:3:3:1, wouldnt the answer be 6/16? The correct answer is 9/16?

Another question, since the cross is between 2 hybrids individuals -AaBbXAaBb, they dont have any genetic relationship?
The parents of a dihybrid cross are-
-they are genetic opposite of each other
-they are genetically identical at the gene of interest
-are genetic opposites t one gene and identical at the other
-no genetic relationship

Thanks in advance

 

[MD Odyssey]

Ek q- In a dihybrid cross, what fraction of the offrspings are likely to be dihybrids?
Since the ratio is 9:3:3:1, wouldnt the answer be 6/16? The correct answer is 9/16?

Another question, since the cross is between 2 hybrids individuals -AaBbXAaBb, they dont have any genetic relationship?
The parents of a dihybrid cross are-
-they are genetic opposite of each other
-they are genetically identical at the gene of interest
-are genetic opposites t one gene and identical at the other
-no genetic relationship

Thanks in advance

On your first question, I'm not sure you're stating the problem correctly. If it is asking how many heterozygous offspring there are, then the correct answer is 4.

To your second question, in a dihybrid cross, the parents are something like RrYy X RrYy. Clearly, these two parents are genetically identical at the gene of interest.

 

[geeyouknit]

Ek q- In a dihybrid cross, what fraction of the offrspings are likely to be dihybrids?
Since the ratio is 9:3:3:1, wouldnt the answer be 6/16? The correct answer is 9/16?


Thanks in advance

I think that the 9:3:3:1 refers to phenotype and not homo/heterzygous.
9 would be dominant for both (could be homo and hetero)
1 would be recessive for both
3 would be dominant for one
3 would be dominant for the other

Not sure what you mean by # of dihybrids? I thought dihybrid just referred to the offspring of a cross of AaBb x AaBb.

Edit: Sorry, I guess dihybrid offspring means AaBb, then there's 4.

 

[inaccensa]

i thought dihybrid meant the hetrozygous offspring. i wasnt too sure either