Chromosome analysis on Central and Southern Italy population of the common toad, Bufo bufo (Amphibia, Anura)

Abstract

Amphibians constitute a very good model to explore the historical aspects of species distributions due to their low dispersal capacity and low individual vagility. Bufonidae are one of the most speciose family of Anura, including taxa, such
as Bufo bufo, widespread in Eurasian regions. We performed a karyological study with standard and sequential C-banding + fluorochromes (Chromomycin A3 (CMA) and Diamidinophenylindole (DAPI) on several tadpoles from different populations of Central and Southern Italy. All the examined tadpoles exhibited the standard Bufo karyotype of 2n = 22 biarmed chromosomes, with the first six pairs larger than the other five (7 - 11) pairs and NOR associated heterochromatin distal on the long arms of the 6th chromosome pair, that was also the only chromosome CMA-positive region. C-banding evidenced centromeric heterochromatin, DAPI positive, on all the chromosomes in all the studied populations from Central Italy. The Southern Italy populations differed in additional paracentromeric C-bands on the short arms of chromosomes 1, 3 and 5. These results support the partition of Central populations of B. bufo from the Southern ones, as evidenced also from molecular phylogenetic studies.