Identification of a new set of molecular markers in Norway spruce as revealed by random amplification techniques

DNA content per haploid genome in conifers is approximately 1-2 orders of magnitude larger than any other plant species (30 to 40 x 109 bps - Miksche e Hotta, 1973; Ohri and Khoshoo, 1986). Previous studies reported the presence of extended regions of repetitive DNA (about 75 % of the total DNA content - Kriebel, 1985; Dhillon, 1987; Cullis et al., 1988; Neale and Williams, 1991). These features of the conifers genome call for a new class of molecular markers in order to extend the genome sampling carried out so far. RAPD markers are obtained by Polymerase Chain Reaction (PCR) amplification of random DNA segments from total genomic DNA with single primers, usually 10-mer of arbitrary nucleotide sequence (Williams et al., 1991). Most of the sequences amplified using this technique turns out to be repetitive DNA (Welsh and McClelland, 1991; Paran et al., 1991; Reiter et al., 1992). Several studies have demonstrated that RAPD markers are not clustered throughout the conifers genome (Neale and Sederoff, 1991; Nelson et al., 1993; Binelli and Bucci, 1994), thus suggesting random sampling. The aim of this study is to describe a new set of Mendelian molecular markers based on RAPD technique. Segregation analysis of 72 megagametophytes from a single individual of Picea abies Karst. is reported. Cosegregation between markers and a linkage map based on the data reported here were published elsewhere (Binelli and Bucci, 1994).