C. Lanner et al., GENETIC VALIDITY OF RAPD MARKERS AT THE INTRA-SPECIFIC AND INTER-SPECIFIC LEVEL IN WILD BRASSICA SPECIES WITH N=9, Theoretical and Applied Genetics, 93(1-2), 1996, pp. 9-14
The sequence homology of co-migrating RAPD markers within a genus, acr
oss species, and among populations of a species was investigated. DNA
was isolated from ten wild Brassica species with n = 9 and the RAPD pa
tterns were established using three random primers. Five RAPD markers
which appeared to be characteristic for the n = 9 species (genus level
), four markers which appeared to be species specific, and one populat
ion-specific marker were isolated from agarose gels and hybridized to
the RAPD profiles of the ten Brassica species. Two RAPD markers were c
loned for comparison with gel-isolated RAPD fragment probes in hybridi
zation experiments. Non-specific and background hybridization, occurri
ng when gel-isolated fragments were used as probes, disappeared when c
loned fragments were used. A total of 250 RAPD-marker hybridizations w
ere scored according to visual presence or absence in a,eel lane. All
except three markers hybridized as expected, resulting in an error rat
e of 1.2%. The deviating results included a lack of hybridization alth
ough a band was visible in the gel, a length polymorphism for one mark
er, and a dual hybridization signal for two single-band markers.