>1a. Doesn't DNA mutate? Even if twins start with identical DNA it could mutate from any number of environmental variables couldn't it? Human DNA does not muta

>1a. Doesn't DNA mutate? Even if twins start with identical DNA it could mutate from any number of environmental variables couldn't it? Human DNA does not mutate that often (If I recall correctly, the average human can expect to see ~230 mutations in their nuclear DNA in their lifetime, this includes that parts of DNA that we believe do nothing) What is far more common is related to epigenetics. Attached to DNA are various promoters and demoters that control how much a given gene is expressed. These can and do change based on envirement. What is also far more common is a mutation in the mitochondrial DNA. However, the only thing mitochondria does for us is to help break down sugars, so mutations in mtDNA are not that significant.