Plant & Animal Genomes XV Conference Plant & Animal Genomes XV ConferenceJanuary 13-17, 2007
Town & Country Convention Center
San Diego, CA
In this presentation, I will describe results from our analyses of the
intergenic and intronic regions of several genomes. Working with the
human genome, we identified large numbers of statistically significant,
distinct, variable-length motifs in its intergenic and intronic regions
with intact copies that total in the millions. A subset of more than one
hundred thousand of these conserved motifs, which we termed "pyknons",
have a total of several hundred thousand instances in the untranslated
and coding regions of more than 90% of all known human genes, in
addition to their numerous human intergenic and intronic copies.
Additional analysis showed that pyknons are enriched in a statistically
significant manner in genes involved in specific processes, e.g., cell
communication, transcription, regulation of transcription, signaling,
transport, etc. Cross-genome comparisons revealed that many human
pyknons have instances in the 3'UTRs of genes from other vertebrates and
invertebrates where they are overrepresented in similar biological
processes, as in the human genome. We also obtained analogous results
from our analyses of a number of other genomes. In fact, we found that
pyknon collections exist in vertebrates and invertebrates, and that they
exhibit similar properties. A notable observation is that pyknon
collections from different genomes have generally little overlap
suggesting that these motifs are organism-specific. I will also discuss
recent experimental evidence from several genomes that provides support
to the hypothesis that pyknons indeed correspond to active molecules
with regulatory role and that they are linked with RNAi. The sheer
numbers of pyknons in a given organism suggests the existence of a very
broad, endogenous layer of organization and cellular process regulation
that remains largely uncharacterized.