Both primers were used for direct sequencing of the PCR products. Sequences of700 bp, corresponding to 16 309 (5′ end) and 17 008 (3′end) of the Xenopus laevis mtDNA (Roe et al, 1985) were obtained for 124 individuals (two to 11 individuals per population). The sequences were aligned using BioEdit,version 1.8 (Hall, 1999) with no indels. Nucleotide diversity(), its standard error and sequence divergence (d)between haplotypes were calculated using DnaSP version 3.14 (Rozas and Rozas, 1999). The nucleotide sequence data have been deposited in GenBank under accession numbers AF329285-AF329314.