Chromosomal and molecular analysis of some repeated families in Discoglossus Otth, 1837 (Anura, Discoglossidae): taxonomic and phylogenetic implications

We conducted a cytogenetic and molecular analysis in sir out of the eight D iscoglossus taxa (D. pictus pictus, D. p. auritus, D. sardus, D. montalenti i, D. galganoi galganoi and D. g. jeanneae) All the taxa possessed 2n = 28 biarmed chromosomes, except D. pictus pictus where the 13th pair was acroce ntric, and the NORs were located on the short arm of the 7th pair in all th e taxa but D. galganoi, where they were on the shea arm of the 13th pair. H eterochromatin was detected by banding methods (C-banding, base-specific fl uorochromes, replication patterns and digestions with restriction enzymes). The techniques used were able to discriminate among all the Discoglussus t axa studied, identifying several heterochromatin families with marked diffe rences in chromosome location and/or in the behaviour of the banding techni ques used. The differentiation of these heterochromatin families can have e ither a phylogenetic (as is the case with A+T rich centromeric heterochroma tin) or an adaptive (G+C rich interstitial heterochromatin) meaning. Hetero chromatin heterogeneity was also observed at molecular level. In D. p. pict us, DNA digestions with restriction enzymes revealed several satellite DNA families. The sequence of the monomeric unit, its chromosomal location and the divergence along the other Discoglossus taxa were detected for one of t hese families (Hind III). The molecular data obtained confirmed the relatio nships suggested by other authors in Discoglossus by osteological and genet ic data.