Genetically stable, individual-specific differences in hypervariable DNA in Norway spruce, detected by hybridization to a phage M13 probe

DNA fingerprinting techniques have significantly improved the resolution of the analysis of genetic polymorphisms in major eukaryotic taxa. The techniques are based on the use of specific DNA probes, which hybridize to families of related minisatellite loci that are dispersed in the genomes of a range of eukaryotes. These sequences are highly variable as a result of a variation in the numbers of a core repeat sequence at each locus. We wanted to establish whether one such probe, the DNA of the bacteriophage M13, could be used to detect hypervariable loci in the conifer Norway spruce, Piceaabies (L.) Karst., and to examine if the method could detect genetic differences at the level of populations and (or) individual trees. The results show that hypervariable minisatellite sequences that hybridize to the M13 probe are present in Norway spruce. The minisatellite sequences are stably inherited, and the variability within the species is sufficiently high to allow the distinction of different individuals. The differences between populations are of the same order of magnitude as those between trees within populations. The method is potentially useful in population genetics research on conifers, as well as in breeding programs.

DNA profilinf of Queensland Koalas reveals sufficient variability for individual identification and parentage determination.

M13 probe was used in combination with the restriction enzymes Msp I and Bam HI to produce DNA profiles of captive and free-range Queensland koalas (Phascolarctos cinereus). The Msp I-M13 combination resulted in profiles with an average of 22 clearly resolvable bands in the 1.5-7.6-kb range. When seven koalas (part of a 40-animal free-range population) were analysed, they exhibited 8-29% band polymorphism (average variation of 17%). The Bam HI-MI3 combination produced 28 resolvable bands with an average of 9% band polymorphism. The Msp I-M13 profiling system was also used to successfully determine paternity in two family groups. Of the 66 total bands produced when mother, father and offspring were profiled, 11 were common to all three family members, nine were unique to the mother and four were unique to the father. However, two maternal-specific and eight paternalspecific bands were inherited by the offspring. DNA profiling of koalas (at least of those from Queensland) should prove useful for assessing the degree of inbreeding in captive populations, solving disputed paternity cases in wildlife poaching, determining the social organisation of free-range koalas, identifying individual koalas and studying the genetics of the koala throughout its range.

DNA Fingerprints in Sports of `Red Delicious' Apples

Hybridization of minisatellite DNA with an M13 probe yields DNA fingerprints that usually are highly cultivar-specific. However, 15 different sports of `Red Delicious' apples (Malus × domestics Borkh.) exhibited almost identical fingerprints. The mutations determining the morphological differences between the sports could not be detected by the minisatellite probe. These hypervariable DNA sequences appear rather stable in apples, making them ideal for differentiating between cultivars derived through genetic recombination but probably not very useful for differentiating between vegetative sports.

Polymorphic regions in plant genomes detected by an M13 probe

A sequence containing two clusters of 15 base pair repeats from the protein III gene in the bacteriophage M13 has been shown to detect hypervariable minisatellites in many animal species. We have shown that this M13 fragment will detect similar sequences in higher plants including monocots, dicots, and gymnosperms. In addition, polymorphisms were demonstrated in three dicot species. The amount of this sequence has no relationship with the size of the genome, chromosome number, or amount of repetitive DNA in the species tested.Key words: bacteriophage M13, monocot, dicot, gymnosperm, restriction fragment length polymorphism.