Mitochondrial DNA variation in the hybridizing fire‐bellied toads,Bombina bombinaandB. variegata

Abstract

Using five restriction enzymes, geographical variation of mitochondrial DNA (mtDNA) in Bombina bombina and B. variegata was studied in samples from 20 locations. Each restriction enzyme produced a species-specific fragment pattern. B. bombina haplotypes A and B were closely related to each other. In contrast, haplotypes A and B of B. variegata formed two distinct lineages. A very distinctive haplotype (C) was found in the Carpathian Mountains, whereas two other haplotypes, D and E (differing by a single AvaI site), were present in western Europe and the Balkans, respectively. Populations polymorphic for haplotypes D and E occurred in the central Balkans where the haplotypes could replace each other clinally. mtDNA sequence divergence between B. bombina and B. variegata was estimated as 6.0-8.1% and 4.7-5.2% between type C and types D/E of B. variegata. The latter divergence is contrary to allozyme and morphological data that place the western and Carpathian B. v. variegata together (Nei's D = 0.07) and separate them from the Balkan subspecies B. v. scabra (Nei's D = 0.18). Broad interspecific correlation among morphology, allozymes and mtDNA types in European fire-bellied toads argues that, despite continuous hybridization (interrupted perhaps during Pleistocene glacial maxima), little or no mtDNA introgression between the species has occurred outside the narrow hybrid zones that separate these parapatric species.

Plant biosystematics with the help of cytology and cytogenetics

“…These data indicate the refugial character of this area of Poland. Studies of Campanula alpina (Ronikier et al 2008), toads (Bombina) (Szymura et al 2000) and newts (Babik et al 2005) are partly concordant with these results since they confirm the existence of refugia in the Carpathians (other than the Balkan one).…”

Genetic Differentiation Among Peripheral Populations of Bombina bombina from Thrace and Anatolia: An Allozyme Analysis

“…Therefore, it is possible to assume that Thracian and Anatolian populations had different ancestral origins and that their founders represent different fractions of the variability of the species. The peripheral and isolated locations of Anatolian and Thracian B. bombina populations and the time of divergence estimated here also suggest that these populations were most likely founded from a northern ancestral population (sensu Szymura et al 2000). This point of view also explains why Anatolian B. bombina was more similar to the northern group, despite their geographic distance.…”

“…Extensive studies on European Bombina have generally focused on genetic analysis of hybrid zones, rangewide mtDNA divergence, and their phylogenetic relationships Pabijan et al 2008;Szymura et al 2000;Szymura andBarton 1986, 1991;Vörös et al 2006). A previous study , which also includes an Anatolian sample of this species, attempted to analyze mtDNA variation in firebellied toads but did not include the Thracian populations.…”

The influence of hybridization on colony structure in the ant species Temnothorax nylanderi and T. crassispinus

“…This suggests that interspecific mating is asymmetrical and involves mostly female sexuals of T. crassispinus and males of T. nylanderi. Asymmetrical or unidirectional mating events are common in hybridizing species (Szymura et al, 2000;Redenbach and Taylor, 2003;Salazar et al, 2005). In our study system, it might result from morphological or behavioral differences between sexuals of the two species or from the prevailing direction of the wind, promoting only a one-way drift of T. nylanderi males to the T. crassispinus site.…”