Fingerprinting Birds' DNA with a Synthetic Polynucleotide Probe (TG)n

Unambiguous determination of genetic relationships is important to understand mating patterns and population structures. For example, thorough social studies of lekking or cooperatively breeding species require that parentage and other close genetic relationships be determined. Similarly, although extrapair copulations (EPC) have been documented in several bird species (e.g. Birkhead 1987, Westneat et al. 1990), some details about the behavior cannot be evaluated unless the result of illegitimate matings can be quantified reliably. Until recently these have been serious obstacles, and although some attempts to use protein variants as genetic markers to determine genetic relationships have been successful, many have been inadequate. Basically this is a consequence of the low degree of polymorphism in protein systems (Mumme et al. 1985, Romagnano et al. 1989). Highly polymorphic markers are required for effective studies of genetic relationships. The discovery of families of hypervariable DNA regions in the human genome led to the development of DNA fingerprinting. The technique screens several hypervariable loci simultaneously to produce individual-specific fingerprints of the DNA (Jeffreys et al. 1985a, b). The technique is also applicable to birds (Burke and Bruford 1987, Wetton et al. 1987), plants (e.g. Dallas 1988), fungi (Braithwaite and Manners 1989), and nematodes (Uitterlinden et al. 1989). In recent avian studies, DNA fingerprinting has provided a powerful method for analyzing parentage (Burke et al. 1989, Gelter 1989, Birkhead et al. 1990, Gibbs et al. 1990, Gyllensten et al. 1990, Rabenold et al. 1990, Westneat 1990; see also Quinn et al. 1987). DNA fingerprinting has traditionally been performed by using genetically cloned human minisatellite probes (e.g. Jeffreys' clones 33.6 and 33.15) or by a tandemly repeated DNA segment present in the wild-type genome of the bacteriophage M13 (see Vassart et al. 1987). Minisatellites derived from other species, including the Willow Warbler (Phylloscopus trochilus), have been used (e.g. Gyllensten et al. 1989). However, synthetic oligonucleotides (15-25 base pairs) with simple repeat motifs (e.g. dior trinucleotide repeats) also produce individual-specific fingerprints in a variety of species (Epplen 1988, Sch•fer et al. 1988, Kashi et al. 1990). Simple repeat motifs are probably present in all eukaryotic genomes and their polymorphism is due to a varying number of repeated units (Tautz 1989). The synthetic polynucleotide probe (TG). detects highly specific DNA fingerprints in horses (Ellegren