TOPO6: a nuclear single-copy gene for plant phylogenetic inference

Abstract

TOPO6, a nuclear gene-marker region of subunit B of the plant homolog of archaean topoisomerase VI, occurs as single-copy locus in the haploid genome of most plant groups. The gene consists mainly of 19 exons and 18 introns, which provide conserved primer binding sites for PCR amplification in many angiosperm families combined with variable sequence stretches that can be explored in molecular systematics. Here intron/exon structure, sequence diversity, and a set of amplification primers are described to use TOPO6 as single-copy phylogenetic marker region in a wide range of plant taxa, either through PCR amplification or hybridization-based sequence capture.