A RAPID PCR-BASED METHOD FOR MAPPING ESTS IN PINUS SPECIES

Genomics Group, Forest Research, Private Bag 3020, Rotorua, New Zealand

DNA marker techniques that enable efficient construction of high density genetic linkage maps are essential if marker-aided selection is to become a standard component of forest tree improvement programmes. Currently, high-throughput EST sequencing projects and automated systems for studying patterns of expression are creating large databases of partial EST sequences in plants and animals. These rapidly expanding databases provide an opportunity to build genetic linkage maps of expressed genes. Ideally, EST mapping methods would be automatable for high-throughput and would reveal high levels of polymorphism. We have developed a PCR-based method which reveals abundant fragment length polymorphisms in the non-coding DNA adjacent to expressed genes. These fragment length polymorphisms are resolved on standard electrophoretic systems and are compatible with automated genotyping platforms. We are using this approach to map ESTs from a range of Pinus species on our P. radiata base map. These "gene maps" will enable us to examine chromosomal regions for associations with phenotypic traits in P. radiata and to align pine linkage maps.