Mutation rate

[Dima]

Which has a higher mutation rate prokaryotes or eukaryotes?

 

This was a question on my exam, i wrote prokaryotes and it was wrong. I was thinking along the lines that prokaryotes have less DNA repairing mechanisms and they divide at a much faster rate than eukaryotes. Can someone please explain to me RIGHT answer to this question, because I'm pretty sure that I am right, or why I am wrong. THanks.

[CharonY]

This is a tricky question in my opinion, and does (again, in my opinion) not have a simple answer. Bacteria under stress for instance, can induce an error-prone repair system which will increase their mutation rate by quite a bit. In addition, mobile genetic elements also act as mutagenic agents, which different organisms. In eukaryotes, different cell types have different mutation rates. Based on that, mutation rates are only rough estimates and are highly dependent on the organism, even the tissue within an organisms and their overall exposure to mutagenic agents. In single celled eukaryotes mutation rate estimates are going to be higher than in more multicellular ones, for instance, as only mutations in the germline are going to be detected (so, it is also slightly a matter of how mutation rates are estimated.

 

Overall, however, due to the fact that they are all single-celled, plus overall higher exposure to mutagenic agents (including mobile genetic elements) plus higher potential of horizontal gene transfer (of which the before mentioned MGEs also play a role) plus error prone repair systems I would think that on average, the estimates for prokaryotes should actually be higher than for eukaryotes.

 

Edit: Repair mechanisms in proakaryotes are actually pretty good and mutation rates are generally adjusted for generation time, so these two answers are not really relevant.

Edited December 3, 2011 by CharonY

[Dima]

This is a tricky question in my opinion, and does (again, in my opinion) not have a simple answer. Bacteria under stress for instance, can induce an error-prone repair system which will increase their mutation rate by quite a bit. In addition, mobile genetic elements also act as mutagenic agents, which different organisms. In eukaryotes, different cell types have different mutation rates. Based on that, mutation rates are only rough estimates and are highly dependent on the organism, even the tissue within an organisms and their overall exposure to mutagenic agents. In single celled eukaryotes mutation rate estimates are going to be higher than in more multicellular ones, for instance, as only mutations in the germline are going to be detected (so, it is also slightly a matter of how mutation rates are estimated.

 

Overall, however, due to the fact that they are all single-celled, plus overall higher exposure to mutagenic agents (including mobile genetic elements) plus higher potential of horizontal gene transfer (of which the before mentioned MGEs also play a role) plus error prone repair systems I would think that on average, the estimates for prokaryotes should actually be higher than for eukaryotes.

 

Edit: Repair mechanisms in proakaryotes are actually pretty good and mutation rates are generally adjusted for generation time, so these two answers are not really relevant.

 

Lol ive been trying to figure this out for days now. Does anyone else know?