Abstract
Abstract: :
Purpose: The macula is the retinal region associated with acute vision. The fovea is the central 1.5 mm wide region of the macula. Given the limited tissue defined by the fovea and the macula, very little is known about this region of the retina at the molecular level. Fovea and macular disorders are both phenotypically and genetically heterogeneous. A significant number of familial retinopathies show linkage with chromosome 6, including the STGD3 disorder that we are studying in a large Canadian family. From our analysis of STGD3 we concluded that a transcript map of chromosome 6 genes expressed in the foveomacular region and in the minimal critical region of our disease locus would be a useful tool in the analysis of familial disease genes that cluster in this region. Our goal has broadened to define the fovea/retinal transcript map of human chromosome 6, Group C human chromosomes, and inevitably the rest of the genome. To pursue this goal, human fovea-expressed cDNA was used to probe EST arrays to identify putative fovea expressed genes. Methods: A human clone array that was gathered in 1996, bearing over 270,000 known human ESTs from various libraries, was screened with human fovea cDNA. In addition more recent collections of ESTs have been screened. ESTs that were positive for the fovea cDNA probe were subjected to in silico analysis using existing, established databases. Results: Of approximately 16,000 foveally-expressed ESTs identified in total, over 1,800 ESTs in this collection of clones mapped to Group C chromosomes (chromosomes 6 through 12). Since 1999 both quantity and quality of the relevant information has increased, indicating both the utility of existing databases and the rate at which said databases are maturing. With the release of the human genome sequence it is now possible to effectively map DNA sequences in silico. Conclusion: This broad approach to identify candidate disease genes of the fovea and macula is viable, particularly in light of the availability of sequence data and the tools to exploit such sources. Our evolving human fovea transcript map will be very useful for positional candidate disease gene approaches.
Keywords: 417 gene/expression • 418 gene mapping • 460 macula/fovea