Landweber and other members of her team are researching the origin and evolution of genes and genome rearrangement, with particular focus on Oxytricha because it undergoes massive genome reorganization during development.
In her lab, Landweber studies the evolutionary origin of novel genetic systems such as Oxytricha's. By combining molecular, evolutionary, theoretical and synthetic biology, Landweber and colleagues last year discovered an RNA (ribonucleic acid)-guided mechanism underlying its complex genome rearrangements.
"Last year, we found the instruction book for how to put this genome back together again -- the instruction set comes in the form of RNA that is passed briefly from parent to offspring and these maternal RNAs provide templates for the rearrangement process," Landweber said. "Now we've been studying the actual machinery involved in the process of cutting and splicing tremendous amounts of DNA. Transposons are very good at that."
The term "junk DNA" was originally coined to refer to a region of DNA that contained no genetic information. Scientists are beginning to find, however, that much of this so-called junk plays important roles in the regulation of gene activity. No one yet knows how extensive that role may be.
Instead, scientists sometimes refer to these regions as "selfish DNA" if they make no specific contribution to the reproductive success of the host organism. Like a computer virus that copies itself ad nauseum, selfish DNA replicates and passes from parent to offspring for the sole benefit of the DNA itself. The present study suggests that some selfish DNA transposons can instead confer an important role to their hosts, thereby establishing themselves as long-term residents of the genome.
|Contact: Kitta MacPherson|