A REPETITIVE AND SPECIES-SPECIFIC SEQUENCE AS A TOOL FOR DETECTING THE GENOME CONTRIBUTION IN SOMATIC HYBRIDS OF THE GENUS MEDICAGO

A highly repeated sequence (C300) was cloned from Medicago coerulea an d its organization in the M. sativa-coerulea-falcata complex, M. arbor ea, and three somatic hybrids involving M. sativa, was investigated. S outhern-blot analysis revealed a tandemly repeated array and a species -specificity of the sequence to those species belonging to the complex . Various degrees of amplification of C300 were detected among the spe cies of the complex and the outcome in the somatic hybrids was depende nt on parental composition. Sequence analysis revealed strong homology (96%) of C300 with a clone (E180) previously isolated from M. sativa. As FISH analysis showed that C300 was dispersed along the chromosomes of Medicago spp., it should prove a valid tool for establishing the c hromosome origin of somatic hybrids.