August 18, 2007 | David F. Coppedge

Mystery of the Ultraconserved Elements, Cont.

ejerano et al reported ultraconserved elements in the human genome (05/27/2004).  These were non-coding regions that, for some unknown reason, showed no evolution between mouse and human – a time span over tens of millions of years.  Since many of these ultraconserved regions are also found in bird genomes, they added that some genetic regions have maintained 100% sequence similarity for 300 million years.
    Now, Bejerano and others have reported in Science that these ultraconserved elements are also ultraselected.1  It appears that strong purifying selection acts three times stronger on these regions than on genes.  The reason for the ultraconserved regions “remains a mystery,” they said.  They could offer no explanation for why natural selection would prevent changes to these sections that are 200 base pairs long and longer.  Whatever they are there for, “These data argue that ultraconserved elements are currently, as well as historically, strongly constrained functional elements.”
Update 09/06/2007: A press release from Berkeley Lab talked about this, calling it a “major challenge to our understanding of how highly conserved elements of the genome persist.”  Mice with one of the ultraconserved elements knocked out appeared to do just fine.  Their paper appeared in the September 2007 issue of PLoS Biology.2

1Katzman, Kern, Bejerano et al, “Human Genome Ultraconserved Elements Are Ultraselected,” Science, 17 August 2007: Vol. 317. no. 5840, p. 915, DOI: 10.1126/science.1142430.
2Ahituv et al, “Deletion of Ultraconserved Elements Yields Viable Mice,” Public Library of Science: Biology 5(9): e234 doi:10.1371/journal.pbio.0050234.

Evolutionists had predicted that once genes could be deciphered, there would be a clear branching pattern of evolution retracing the assumed millions of years of steady evolutionary change.  The more “diverged” the groups, the more the genetic differences would be found.  Well, that picture has not materialized.  So now, Darwinites, since you have displayed ineptitude in finding the way to the future of biology, will you get out of the driver’s seat?

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Categories: Genetics

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