hi, just doing some genetics study and hoping to get some help. when interference occurs chrosmosomal crossovers, interference causes the number actuall number off crossovers observed to occur LESS than expected. what does it mean if you observe MORE crossovers than statistically expected? is this also interference or something else?
genetics study questions please help
- Thread starter icemaiden
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"It has been known for decades that the presence of a crossover on a chromosome usually reduces the frequency of a crossover nearby-that is, crossovers are not found at random with respect to each other. This is known as interference, and the molecular mechanism is not understood. "
I found this on a we site. this also seems to say interference only has a negative affect.?
I found this on a we site. this also seems to say interference only has a negative affect.?
A crossover is more likely to occur the further 2 genes are apart on the chromosome. If 3 linked genes are close together then the one crossover can interfere with the initiation of a second crossover. Therefore when genes are closer together, the interference is high and the frequency of double crossovers will be much lower, or even undetectable. This is positive interference. Negative interferece increases the chance of a second crossover. This is apparently very rare and so I can't really explain it or provide examples...that's just what my text book told me 
(a few sites I have loooked at also mention both positive and negative interference but they don't really go into detail).
(a few sites I have loooked at also mention both positive and negative interference but they don't really go into detail).