q_____________? - sarim

[ArchivalUser]

For X and Z to be together, there must have been no cross-linking between these two genes.

The chances that there has been no cross-linking between X and Y is 25%,
the chanche that there has been no cross-linking between Y and Z is 50%.

both events must occur

then, the probability is 25%.50% = 12,5%

but, another possible way (with slight chances) for X and Z to be together is that 2 cross-linking happened
that's why I believe the answer is 13%, and not the exact 12,5%

[ArchivalUser]

It's a Q from old USMLE Sample Qs.

I do not have answer or explanation for it.


-I think "C" is right.

Probability of Gene "X" to be linked with Gene "Y" = 0.25 (25%)
Probability of Gene "Z" to be linked with Gene "Y" = 0.50 (50%)

so if we want to know the probability of "Both Genes" (X and Z) to be linked with Gene "Y' together, all we have to do is Multiply the above two probabilities.

Probability of Both Genes (X and Z) to be linked with Gene "Y together = 0.25 * 0.50 = 12.50%

and option "C" is the better option


I know it's a nut Q

[ArchivalUser]

X and Z might also be together, when 2 cross linking happens

there might be one permutation between X and Y, AND another one between Y and Z, making X and Z still together

12,5% is the probability that X and Z are together and NO permutation happened between them

therefore, 13% is a better answer then "exactly 12,5%"

[ArchivalUser]

...X....Y.....Z
X
Y
Z
...................
XX..XY...XZ
XY..YY...YZ
XZ..YZ...ZZ
.................
25%..XY
50%..YZ
................25%(XX,YY,ZZ,2XZ)....1/5 for each one....5%
2XZ....10%


..the recombination /crossing over also plays role...if the gene are on the same chromosom and far apart..(X-Y-Z).the allels will remain together about 50% of the time..
I think ~50% of 10%....~5%....so the chance of x and z being transferred together is more than 10 and less than 15....
C is the best choice