F10, the gene for the glycine-rich major eggshell protein ofSchistosoma mansonirecognizes a family of hypervariable minisatellites in the human genome

F10, the gene encoding the major eggshell protein of the parasitic trematode Schistosoma mansoni has been recently cloned and sequenced (1, 2). The nucleotide sequence predicted a protein with 160 amino acids and a 48.7% content of glycine. Most of the glycines are in a stretch extending from amino acid 25 to 112, corresponding to nucleotides 329 to 593 in the gene sequence. We aligned this stretch trying to maximize its internal homology and were able to deduct a 12 base pair consensus repeat motif TATGGTGGTGGT. This motif was clearly homologous to the CHI (Crossover Hostspot Instigator -GGCGGTGG) sequence of Escherichia coli (3). Also similar to CHI in sequence and G content are several multilocal human DNA fingerprinting probes, such as those derived from the human myoglobin gene (4), the protein m gene of M13 phage (5) and the oligonucleotide (CAQ5 (which recognizes the target (GGT),,) (6). On this basis, we predicted that F10 should also be able to recognize a family of minisatellites in the human genome. F10, cloned in M13MP10 (1), was biotin-labeled as described previously (7) and hybridized to human genomic DNA digested with BspRl (an isoschizomer of HaeUI). As predicted, a complex and highly variable DNA fingerprinting pattern was obtained. The figure shows the DNA fingerprints of two unrelated individuals. Analysis of 62 unrelated persons showed an average of 21.5 resolvable bands per individual, with a 22% overall band sharing. Thus, F10 is a very informative multilocal probe, and its efficiency in paternity testing should be comparable to each of Jeffreys' 33.6 and 33.15 probes (4). The genetic code for glycine is GGN and the complementary triplet CCN codes for proline. Thus, any gene encoding glycinerich or proline-rich internally repetitive proteins should also present tandem motifs homologous to CHI which should serve as multilocal probes for DNA fingerprinting in man and other species. REFERENCES