SEQUENCE-TAGGED-SITE (STS) MARKERS OF ARBITRARY GENES - THE UTILITY OF BLACK SPRUCE-DERIVED STS PRIMERS IN OTHER CONIFERS

Sequence-tagged-site primers, previously developed based upon black sp ruce (Picea mariana) cDNA sequences, were tested for their ability to direct specific amplification in two individuals of each of 12 additio nal conifer species. Nearly all (95-97%) of the primers functioned wel l in congeneric trials, while a lower proportion (21-33%) scored posit ively in other Pinaceae genera. Outside of the Pinaceae, amplification of homologous products was not achieved. Products from the various sp ecies often differed in size from their homologs in black spruce. In o ne case a large difference in size was due to the lack of an intron in a jack pine product while in several other cases the differences were due to the presence or absence of large direct repeats in the DNA seq uences. Length polymorphism was occasionally evident between the two i ndividuals examined of a given species. We investigated marker polymor phism in detail in a panel of 15 white spruce (Picea glauca) trees. Al lelic segregation among haploid megagametophytes was revealed directly at 16 loci by standard agarose-gel electrophoresis without any additi onal manipulation of amplification products. Poly morphisms observed a t 12 of these loci were exclusively co-dominant. For this subset of 12 loci, the average number of alleles was 3.2 and the average observed heterozygosity was 0.37.