Diversity and evolution of mitochondrial RNA editing systems.
Department of Biochemistry and Molecular Biology, Dalhousie
University, Halifax, Nova Scotia, B3H 1X5, Canada. M.W.Gray@...
'RNA editing' describes the programmed alteration of the nucleotide
sequence of an RNA species, relative to the sequence of the encoding
DNA. The phenomenon encompasses two generic patterns of nucleotide
change, 'insertion/deletion' and 'substitution', defined on the basis
of whether the sequence of the edited RNA is colinear with the DNA
sequence that encodes it. RNA editing is mediated by a variety of
pathways that are mechanistically and evolutionarily unrelated.
Messenger, ribosomal, transfer and viral RNAs all undergo editing in
different systems, but well-documented cases of this phenomenon have
so far been described only in eukaryotes, and most often in
mitochondria. Editing of mRNA changes the identity of encoded amino
acids and may create translation initiation and termination codons.
The existence of RNA editing violates one of the long-accepted tenets
of genetic information flow, namely, that the amino acid sequence of
a protein can be directly predicted from the corresponding gene
sequence. Particular RNA editing systems display a narrow
phylogenetic distribution, which argues that such systems are derived
within specific eukaryotic lineages, rather than representing traits
that ultimately trace to a common ancestor of eukaryotes, or even
further back in evolution. The derived nature of RNA editing raises
intriguing questions about how and why RNA editing systems arise, and
how they become fixed as additional, essential steps in genetic
Intelligent design creationists claim this kind of paper provides
strong arguments for them.
They claim that the article properly describes `RNA editing' as a
programmed alteration presents a problem that such code can not
evolve through small, incremental steps.
They claim that the authors note that "particular RNA editing systems
display a narrow phylogenetic distribution, which argues that such
systems are derived within specific eukaryotic lineages, rather than
representing traits that ultimately trace to a common ancestor of
eukaryotes, or even further back in evolution." since they can't find
a common ancestry thread so they have to rely on the independent
evolution of these complex RNA editing systems, which is is called
convergence, something that is prevalent in nature and by its very
definition is anti-evolutionary.
because it is used to describe traits that cannot be attributed to
common decent. Intelligent designers argue that convergence is yet
another signature God has left in his creation to thwart attempts to
explain things via naturalistic processes.
However, this article supports a living earth, which is pre cellular.
In short, nucleotides in cirrus are sorted by electro mechanical
movements between conductive ionosphere and cloud tops. The charge of
the nucleotide allows cirrus to be ordered in bands in the
atmosphere, just like electrophoresis bands the nucleotides. The
banding then provides a biological feedback of temperature and rain
back down on a earth, and the nucleotides rain, sorted by electrical
and genetic conditio INDEPENDANT OF FUNCTIONING. This sorting was the
start of life, and was precellular and would have caused an
assortment of like ion behaving sequences. These sequences then
converged as they became more efficient at various replicating
processes, or became FUNCTIONAL. To make an arguement that this
process supports some means that is not naturalistic is absurd and
supported by no evidence or science or theory.