One result of the international project came as a bit of a shock. Scientists discovered that the body has only 30,000 genes, far fewer than the 50,000 to 140,000 they had expected to find.

Moreover, scientists learned that some less complex, less diverse organisms had more, or proportionally more genes than human beings. The rice genome contains 50,000 genes and the fly 14,000, to cite two examples.

The lack of correlation between genome size and an organism's complexity raised a question - how do complexity and diversity arise in higher life forms?

The unexpected finding, says Stefan Maas, necessitates a clearer understanding of the role played in protein diversity by processes that take place after DNA is transcribed to RNA and after RNA is translated to proteins.

Maas, an assistant professor of biological sciences, studies RNA editing, a phenomenon discovered in ion channels of the brain a decade ago at the University of Heidelberg in Germany, where Maas earned his Ph.D.

RNA editing involves the process by which cells use their genetic code to manufacture proteins. More specifically, says Maas, RNA editing "describes the posttranscriptional alteration of gene sequences by mechanisms including the deletion, insertion and modification of nucleotides." Nucleotides are compounds that form the basic constituents of DNA and RNA.

Often working in tandem with another RNA modification mechanism called alternative splicing, RNA editing, says Maas, can "increase exponentially the number of gene products generated from a single gene."

A greater understanding of RNA editing, scientists believe, might potentially shed light on evolutionary processes and might lead to new strategies for combatting some diseases. In fact, says Maas, scientists have l
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Contact: Kurt Pfitzer
kap4@lehigh.edu
610-758-3017
Lehigh University
4-Jan-2005