Is chromosomal crossover considered a mutation? Would this be a large-scale mutation?
2 Answers
There are many different ways a DNA sequence can change. Labeling a change as a mutation implies that there was a biological process in which DNA was damaged then not properly repaired.
Crossing over during the formation of gametes does not result in a mutation.
Crossing over during repair of a double stranded DNA break does result in a mutation.
Yes. And it is especially considered a large-scale mutation when compared to point mutations which effect single bases.
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3$\begingroup$ I disagree with this answer. Have a look at the Wikipedia pages for mutation and recombination. Crossing-over may create new combinations of existing alleles/SNPs but it does not create any new ones. Even if there is a piece of sophistry which can be devised to defend this answer it is neither helpful nor useful to lump these two together as one. $\endgroup$ Sep 3, 2014 at 18:06
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$\begingroup$ The scale of a mutation is not simply a matter of counting bases. A frame shift mutation from a nucleotide deletion completely changes a translated protein. However, a change in any number of bases in a gene would only affect those bases, not the entire gene. The 'scale' of a mutation is situationally dependent. $\endgroup$ Sep 3, 2014 at 22:16