Coding and Non-coding DNA
Location: Outside U.S.
Date: September 2008
What are the evolutionary differences between coding and non
coding DNA? is the mutational force on non coding DNA higher than coding
First of all, non-coding has traditionally meant DNA that doesn't code
for protein. New research shows that this much of this DNA is probably very
important in regulating whether genes are on or off, or codes for RNA other
than mRNA. Some of it resembles virus DNA and could be remnants of past viral
infections in our ancestors that has been passed down over the generations.
Some of it resembles other genes but has some mistake in that has inactivated
it-we call these pseudogenes. Sometimes genes get duplicated so that there
are 2 copies of the same gene.
If one of these mutates and becomes inactive
but the other still works it doesn't affect survival. So to answer your
question-some of this non-coding DNA is probably very important to the way
our DNA works and is selected for. Other DNA is not selected for or against
and it hitching a ride through evolutionary time. However, since if mutations
happen in this DNA it doesn't affect our survival, these differences
accumulate and can be used to determine how closely or distantly related two
organisms are evolutionarily. The fewer mutations between two organisms, the
more closely related they are through common ancestry. The more differences,
the more time has passed since they shared a common ancestor.
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Update: June 2012