DNA Markers in Eucalyptus with Emphasis on Species Identification

Abstract

I review the current knowledge on molecular markers for Eucalyptus species, with particular emphasis on individual identification and the prevention of escape of transgenes from transgenic Eucalyptus. Species-specific bands have been found in inter simple sequence repeat (ISSR) markers. Microsatellites are highly polymorphic genetic regions that allow precise discrimination of closely related individuals. Random amplified polymorphic DNA (RAPD) markers are also very useful for individual identification and map construction, although they have limited transferability because they are dominant markers with only two alleles. The amplified fragment length polymorphism (AFLP) technique facilitates the production of high-coverage parental maps in interspecific crosses of eucalypts. Genetic diversity in the continuously distributed Eucalyptus species has been investigated using nuclear restriction fragment length polymorphism (RFLP) loci. Chloroplast DNA, 5S rDNA genes, and ITS regions have proven to be useful in phylogenetic, population, and evolutionary studies of Eucalyptus. Genetic association studies using SNPs are in progress with several Eucalyptus species. Furthermore, microarray technology holds the promise of parallel analysis of thousands of markers in Eucalyptus. Early screening of hybrids with transgenic Eucalyptus using DNA markers will be important to prevent escaping transgenes.