Campbell Biology (10th Edition)

Published by Pearson
ISBN 10: 0321775651
ISBN 13: 978-0-32177-565-8

Chapter 25 - 25.5 - Concept Check: 3

Answer

At least some noncoding DNA (such as miRNA, siRNA) does have significant effects on gene expression since these sequences can alter gene expression by binding to RNA or by binding to and altering chromatin, making genes less accessible for expression. Thus, by their contribution to phenotypes subject to natural selection, at least some noncoding sequences would be affected by natural selection.

Work Step by Step

Review Concept 18.3 and pay attention to how the RNAs there listed change the expression of genes at the level of mRNA or the production of mRNA. Phenotype is what natural selection acts on. This obviously alters any gene expression which changes phenotype, making them subject to evolutionary change. It's like a magazine cover for a magazine containing plans to build furniture-- the cover doesn't contain the information but it affects whether you buy (select) the magazine and build the furniture and, thus, how much of the market (like a population in evolution) the particular magazine occupies.
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