Posted 02 July 2013 - 02:55 AM
Well, your equation is a right one for calculating the genetic distance from two linked genes/markers, like A/a and B/b, where it's used to calculate from the percentage in the cross between a dihybride Ab/aB and recessive ab/ab parents, creating parental Ab/ab, aB/ab and recombinant ab/ab and AB/ab genotypes in the offspring. But as I said I failed to fill in the given numbers and crossing schemes into this calculation, so first of all I don't know if the equation used is actually the right one for this case. I can't tell what are the genotypes here from the sentence "results for marker A were 60 CC, 10 CL, and 4 LL" , as this is very different from the usuall settings (mentioned above) I'm used to.
But if we assume it is right, from that equation, the results should be 5.4, 18.9, 12.2 or 9.5 % (for easier calculations I took 0.054, 0.189 and so on, not multiplied by 100). And the divisor in this equation should be always the overall number of the whole offspring so 60+10+4 in this case. From knowing the possible answers and the divisor, you can calculate the number of recombinants supposed for each answer.
From your calculation you obviously took 10 as number of recombinants, to get 0.1351. I assumed the number of recombinants unknown, using the possible answers:
distance (i.e. 0.054) = x/74 -> x=~4
So we are still stuck with the same problem, I don't get the task setting and therefore I'm not sure if the equation is right or not in the first place. If you do understand the setting maybe if you can scheme out the crossing it may shed some light for me.
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