Congruence between allozyme and cytochrome b gene sequence data in assessing genetic differentiation within the Iberian endemic Chondrostoma lemmingii (Pisces: Cyprinidae)

Abstract

To understand further the fragmentation of the hydrographical basins and the processes of divergence and speciation of freshwater fishes of the Iberian Peninsula, 10 populations of the Iberian endemic cyprinid Chondrostoma lemmingii were studied using 26 loci encoding 19 enzymes and the complete nucleotide sequence of the mitochondrial cytochrome b gene. Nuclear and mitochondrial DNA markers showed complete congruence in assessing the genetic differentiation among the samples analysed. This congruence was supported by a Mantel test in which a significant correlation (r=0.89) between Nei's genetic distances and sequence divergence (uncorrected p distances) was obtained. Diagnostic loci, Nei's genetic distances, and FST values, as well as the percentage of sequence divergence indicate that the Duero basin population accumulates the highest level of genetic differentiation. A moderate divergence was also observed among populations of the rest of the basins. Phenetic and phylogenetic relationships support the hypothesis that the differentiation process was not only due to hydrographical basin isolation but also due to an ancient endorrheism event, previous to hydrographical configuration, that could explain the marked differentiation of the Duero basin population.

Mitochondrial DNA signatures at different spatial scales: from the effects of the Straits of Gibraltar to population structure in the meridional serotine bat (Eptesicus isabellinus)

“…A similar north-south dispersion pattern has been suggested for lizards (Carranza et al, 2006) and freshwater turtles (Fritz et al, 2006). Southwest Iberia seems to have been an important refugium for a variety of species, from cork oaks (Ló pez de Heredia et al, 2007), to fish (Carmona et al, 2000) and aquatic invertebrates (Gó mez et al, 2000;Muñ oz et al, 2008). Despite the need for additional data, our results support the idea that the Iberian Peninsula and, in particular, southwestern Iberia acted as a refugium and genetic source region for both European (Taberlet et al, 1998;Hewitt, 1999), and NorthAfrican biotas.…”

Evolutionary and biogeographical patterns within Iberian populations of the genus Squalius inferred from molecular data

“…Despite the general pattern of differentiation of populations among basins, supported by the AMOVA analysis, we can observe both small interdrainage genetic divergences in some neighbor basins, and high intradrainage genetic divergences in some basins like Tajo and Guadalquivir with a more complex paleogeographical history (Carmona et al, 2000). Those results show that the influence of ancient endorrheic lagoons that originated some of these main rivers can still be detected.…”

“…Those results show that the influence of ancient endorrheic lagoons that originated some of these main rivers can still be detected. The impact of these paleogeographical events in the generation of genetic diversity has also been observed in populations of Chondrostoma lemmingii (Carmona et al, 2000) for which the Duero basin population constitutes a new species. The population from the upper Guadalquivir should started to diverge in the south of the Iberian Peninsula prior to the complete isolation of Guadiana basin.…”

Phylogenetic relationships and the evolution of regulatory gene sequences in the parrotfishes

“…However, the strength of phylogenetic signal at the species level was less balanced, with cytochrome b, a gene often used in population genetic studies in fishes (Carmona et al, 2000;Feulner et al, 2007), providing half of the sites informative for parsimony within the 24 Scarus taxa. At the species level, the "standard" phylogenetic markers (12s, 16s, tmo4c4, and rag2) and regulatory gene fragments (bmp4, dlx2, and otx1), showed similar resolving power and similar phylogenetic structure (Fig.…”