Re:Astronaut’s DNA No Longer Matches His Identical Twin’s Af...
by gus_massa on Thursday March 15, 2018 @02:08PM
(#16595172)
I am not a biologist, so my answer may have a mistake ...
Radiation and cosmic rays produce random mutations, where one of the bases of the DNA is changed by another base. (IIRC the radiation breaks the old base, and when the copy or correction enzymes see the mess, they may make a mistake and use the wrong base.)
Methylation is on purpose. Some part of the cell "decides" to enable or disable a gen, and send the correct enzymes to add or remove the methyles in the bases of the specific part of the gene.
(There are also some arm races between bacteria and virus that attack bacteria. The bacteria has an enzyme that split the DNA at points with some specific patterns, to try to kill the virus that enter the cell. The parts of the DNA of the bacteria with this pattern are methylated, so the enzyme doesn't attack the DNA of the owner. https://en.wikipedia.org/wiki/Restriction_modification_syste... )
Radiation and cosmic rays produce random mutations, where one of the bases of the DNA is changed by another base. (IIRC the radiation breaks the old base, and when the copy or correction enzymes see the mess, they may make a mistake and use the wrong base.)
Methylation is on purpose. Some part of the cell "decides" to enable or disable a gen, and send the correct enzymes to add or remove the methyles in the bases of the specific part of the gene.
(There are also some arm races between bacteria and virus that attack bacteria. The bacteria has an enzyme that split the DNA at points with some specific patterns, to try to kill the virus that enter the cell. The parts of the DNA of the bacteria with this pattern are methylated, so the enzyme doesn't attack the DNA of the owner. https://en.wikipedia.org/wiki/Restriction_modification_syste... )