Conserved Nucleic Acid Sequences
Highly conserved DNA sequences are thought to have functional value. The role for many of these highly conserved non-coding DNA sequences is not understood. One recent study that eliminated four highly-conserved non-coding DNA sequences in mice yielded viable mice with no significant phenotypic differences; the authors described their findings as "unexpected".
Many regions of the DNA, including highly conserved DNA sequences, consist of repeated sequence (DNA) elements. One possible explanation of the null hypothesis above is that removal of only one or a subset of a repeated sequence could theoretically preserve phenotypic functioning on the assumption that one such sequence is sufficient and the repetitions are superfluous to essential life processes; it was not specified in the paper whether the eliminated sequences were repeated sequences.
The TATA promoter sequence is an example of a highly conserved DNA sequence, being found in most eukaryotes.
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