Grant: Discovery Grants Program - Individual

The completion of the human genome sequence has provided us with a wealth of data about the number, types, and organization of the genes required to encode a human. Functional analysis of the genomes of other organisms, such as the fruit fly Drosophila melanogaster and the worm Caenorhabditis elegans, is also being done to try to make sense of the human genome. Comparisons of these different genomes will also help us to determine how genomes of all organisms evolved. Current theories of genome evolution include the concept that new genes arise by a process of gene duplication. Gene duplication can occur by different processes, including doubling of the whole genome, duplication of a part of a chromosome, or copying of a single gene. Once a gene is duplicated, one of the copies can be inactivated or, in rare cases, it can acquire a new function by a change in its DNA, or mutation. It is thought new functions of duplicated genes are an important force in the diversification of life. Another source of genetic diversity comes from virus-like sequences, called retrotransposons, found in our genome and those of other organisms. These sequences copy themselves and insert into other sites of the genome. However, they can also make copies of gene products which insert into new sites. This type of gene duplication is called retroduplication. The patterns of their evolution and the mechanism of their production aren't yet well defined. Now that we have several genome sequences in hand, we can ask 1) what parts of retroduplicated genes changed by mutation? 2) do retroduplicated genes have the same or different functions? 3) if a retroduplicated gene acquires mutations that knock out its original function, can it have a new function? 4) what are the mechanisms for retroduplication? This research program will address these questions using the Drosophila genome and genes from other insect species. Computer analysis of gene sequences and the tools of genetics and molecular biology will be used to answer these questions. The answers will help us to understand the process of how genes diversify in function and its significance for organismal evolution.