Assignment of BReast Cancer Associated 1 <i>(BRCA1)</i> to tammar wallaby <i>(Macropus eugenii)</i> chromosome 2q3 by in situ hybridization

BRCA1, located at 17q21.31 in humans, is a significant gene in familial breast and ovarian cancer. BRCA1 functions as an important regulator of pathways governing DNA repair, cellcycle progression, ubiquitylation and transcriptional regulation in mammals. Orthologs are not found in the yeast, fly or worm genomes (Venkitaraman, 2002; Narod and Foulkes, 2004). Previously SOX9, located at 17q24.3 in humans, was mapped to the long arm of chromosome 2 in the tammar wallaby (Pask et al., 2002). Therefore mapping of the tammar wallaby BRCA1 homologue to chromosome 2q3 has extended the region of synteny with human chromosome 17q by 29 megabases, identifying a large segment of a chromosome block (C14) that is conserved in marsupial evolution (Rens et al., 2003).