Genomic analysis in maritime pine (Pinus pinaster). Comparison of two RAPD maps using selfed and open-pollinated...

Two genomic maps were constructed for one individual tree of maritime pine, Pinus pinaster Ait., using a common set of 263 RAPD markers (random amplified polymorphic DNA). The RAPD markers were chosen from a larger number of polymorphic RAPD fragments on the basis of repeatability and inheritance in a three-generation pedigree. The maps were constructed from two independent mapping samples of 62 megagametophytes (In) from a self cross and from an open-pollinated cross. The markers were grouped (LOD≥4; θ≤0.25) and assigned to 13 major and 5 minor linkage groups. Two framework maps were constructed using the ordering criterion of interval support≥3. Comparison of the two framework maps suggested that the locus order was incorrect for 2% of the framework markers. A bootstrap analysis showed that this error rate was representative for our data set. The results showed that framework maps constructed using RAPD markers were repeatable and that differences in locus order for maps of different genotypes or species could result from chance. The total map distance was 1380 cM, and the map provided coverage of approximately 90% of the genome.