Microsatellite development and inheritance in the planarian flatworm Schmidtea polychroa

We developed four polymorphic microsatellite loci for the hermaphroditic planarian Schmidtea polychroa and used them to identify differences in recombination rate in the male and female germ line. DNA isolation protocols were optimized for tissue from adults and hatchlings. The final PCR protocols and profiles yielded repeatable and reliable amplification. Null alleles detected at one locus could be avoided by redesigning one primer. Routine genotyping was established using fluorescent-labeled primers and an ABI 310 automated sequencer. They amplify successfully in a number of populations. The four loci are characterized by extreme within-population polymorphism, with 15 to 20 alleles per locus in a standard sample. All four have been submitted to GenBank. Two loci (SpATT16, SpATT18) appeared to be coupled. From parent-offspring comparisons, the recombination fraction could be estimated, which was significantly different for the male (c = 0.07) and female (c = 0.23) line. High overall exclusion rates for first (>0.94) and second parent (>0.98) even with three (unlinked) loci demonstrates the suitability of these microsatellites for other applications such as parentage analysis.