GENOMIC MAPPING IN PINUS-PINASTER (MARITIME PINE) USING RAPD AND PROTEIN MARKERS

A detailed genomic map was constructed for one F-1 individual of marit ime pine, using randomly amplified polymorphic DNA (RAPD) and protein markers scored on megagametophytes of germinated seeds. Proteins allow ed the localization of exclusively coding DNA in the large genome of t his Pinus species, mapped with RAPD markers that essentially fall with in repetitive (i.e. mostly noncoding) DNA. Dot blots experiments of 53 RAPD fragments showed that 89 per cent amplified from highly repetiti ve chromosomal regions. The map comprised 463 loci, including 436 RAPD s amplified from 142 10-mer oligonucleotide primers and 27 protein loc i. Twelve major and one minor linkage groups were identified using a L OD score less than or equal to 5 and a recombination fraction Theta le ss than or equal to 0.30. A framework map was ordered with an interval support greater than or equal to 4, covering 1860 cM which provided a lmost complete coverage of the maritime pine genome. The average dista nce between two framework markers was, 8.3 cM; only one interval was l arger than 30 cM. Protein loci were well distributed throughout the ma p. Their potential use as anchor points to join RAPD-based maps is dis cussed. Finally, the genomic maps of Arabidopsis and maritime pine wer e compared. Linkage groups were shown to have similar total map length s on a chromosomal basis, despite a 57-fold difference in DNA content.