Microsatellite markers for the relict tree Aextoxicon punctatum: the only species in the Chilean endemic family Aextoxicaceae.
We screened 10 microsatellite loci for the dioecious, rainforest tree Aextoxicon punctatum, a species belonging to a monotypic family and genus, endemic to southwestern South America (30-43°S). Polymorphisms were evaluated in 108 adult trees from four populations, including the northern and southern extremes of the geographic range of Aextoxicon in Chile. All 10 microsatellites revealed polymorphic variation. A total of 69, 57, 59, and 69 alleles were found in 40 (Fray Jorge), 19 (Santa Ines), 21 (Quebrada del Tigre), and 28 (Guabun) individual trees, respectively. The mean expected heterozygosity per population ranged from 0.70 to 0.72. These polymorphic microsatellites will be useful in assessing the genetic structure and conservation status of Aextoxicon throughout its historically fragmented geographic range. Parentage analysis will provide additional insights into the key historical and contemporary processes that have mediated population differentiation in this species.