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View Full Version : What is true/not true about linked genes?


ifearone
Nov 4, 2007, 10:35 AM
I'm trying to clarify concepts in genetics about linked genes. I know that linked genes are located on the same chromosome and they always segregated together during meiosis and always separate during crossing over, right? And is the recombination frequency actually reprsent the distance between two linked genes? Also, linked genes always fail to display a 9:3:3:1 ratio in the F2 generation of a dihybrid cross, am I correct?

templelane
Nov 6, 2007, 12:46 PM
I know that linked genes are located on the same chromosome and they always segregated together during meiosis and always seperate during crossing over, right?
Almost right but it doesn't read queit right. It should be more like,
"Genes which are located withing close proximity if one another know as linked, will cosegregated during meiosis unless crossing over occurs."



And is the recombination frequency actually reprsent the distance between two linked genes?
Simplistically yes, but it doesn't map exactly, the recombinant freqency can be high but the distance shorter than another recombinant frequency of the same value. Proximity to the centrosome can cause this. However unless this is mentioned in your notes I wouldn't worry about it.



Also, linked genes always fail to display a 9:3:3:1 ratio in the F2 generation of a dihybrid cross, am I correct?
Yep

I think you seem to have a pretty good understanding on what is going on. Once you understand this stuff it really doesn't get any harder. :)