RESUMEN
Translocations of Baltic whitefish (Coregonus sp.) into Austrian Alpine lakes have created 'artificial hybrid zones', threatening the genetic integrity of native lineages. We evaluate the genetic structure of Coregonus in Austrian lakes and characterize hybridization and introgression between native and introduced lineages. Fifteen populations (N=747) were assessed for allelic variation at eight microsatellite loci and a reduced set (N=253) for variation across two mtDNA genes (cyt b and NADH-3). Bayesian approaches were used to estimate individual admixture proportions (q-values) and classify genotypes as native, introduced or hybrids. q-value distributions varied among populations highlighting differential hybridization and introgression histories. Many lakes revealed a clear distinction between native and introduced genotypes despite hybridization, whereas some locations revealed hybrid swarms. Genetic structure among lakes was congruent with morphological divergence and novelty raising speculation of multiple taxa, including a population south of the Alps, outside the putative native range of Coregonus. Although statistically congruent with inferences based on nuclear markers, mitochondrial haplotype data was not diagnostic with respect to native and non-native lineages, supporting that the Alpine region was colonized post-glacially by an admixture of mtDNA lineages, which coalesce >1 Ma. Mechanisms promoting or eroding lineage isolation are discussed, as well as a high potential to conserve native Alpine lineages despite the extensive historical use of introduced Baltic stocks.
Asunto(s)
Flujo Génico/genética , Hibridación Genética/genética , Salmonidae/genética , Animales , Austria , Teorema de Bayes , ADN Mitocondrial/genética , Ambiente , Variación Genética , Genotipo , Haplotipos/genética , Lagos , Repeticiones de Microsatélite/genética , Fenotipo , Filogeografía , Salmonidae/clasificación , Especificidad de la EspecieRESUMEN
The highly polymorphic CYP2D6 protein metabolizes about 25% of commonly used drugs and underlies a broad spectrum of drug responses among individuals. In contrast to extensive knowledge on the human CYP2D6 gene, little is known about the gene in non-human mammals. CYP2D6 mRNA from 23 cats (Felidae) spanning seven species were compared to available CYPD6 sequences in ten additional mammals and multiple allelic variants in humans. A relatively high mean dN/dS ratio (0.565) was observed, especially within Felidae. Pairwise dN/dS ratios were non-monotonically distributed with respect to evolutionary distance suggesting either positive selection or retention of slightly deleterious mutations. Positive selection on specific codons, most notably in regions involved in substrate recognition and membrane anchoring is supported and the possible influence of diet on specific amino acid changes in substrate binding sites is discussed.
Asunto(s)
Citocromo P-450 CYP2D6/genética , Felidae/genética , Secuencia de Aminoácidos , Aminoácidos/química , Animales , Teorema de Bayes , Gatos , Evolución Molecular , Variación Genética , Humanos , Mutación INDEL , Funciones de Verosimilitud , Modelos Genéticos , Mutación Missense , NADH Deshidrogenasa/genética , Proteínas Nucleares/genética , Mutación Puntual , Estructura Secundaria de Proteína , Análisis de Secuencia de ADNRESUMEN
The soil and moss dwelling oribatid mite family Scutoverticidae is considered to represent an assemblage of distantly related but morphologically similar genera. We used nucleotide sequences of one mitochondrial (COI) and two nuclear (28S rDNA, ef-1alpha) genes, and 79 morphological characters to elucidate the phylogenetic relationships among 11 nominal plus two undescribed European mite species of the family Scutoverticidae with a particular focus on the genus Scutovertex. Both molecular genetic and morphological data revealed a paraphyletic genus Scutovertex, with S. pictus probably representing a distinct genus, and Provertex kuehnelti was confirmed as member of the family Scutoverticidae. Molecular genetic data confirmed several recently described Scutovertex species and thus the high species diversity within this genus in Europe and suggest that S. sculptus represents a complex of several cryptic species exhibiting marked genetic, but hardly any morphological divergence.
Asunto(s)
Evolución Molecular , Especiación Genética , Ácaros/genética , Filogenia , Animales , Teorema de Bayes , Núcleo Celular/genética , ADN Mitocondrial/genética , Europa (Continente) , Ácaros/anatomía & histología , Ácaros/clasificación , ARN Ribosómico 18S/genética , Análisis de Secuencia de ADNRESUMEN
We developed 18 polymorphic microsatellite markers for Coregonus lavaretus from genomic libraries enriched for (GACA)(n) and (GATA)(n) repeat sequences. Emphasis was placed on developing highly polymorphic, perfect repeats. These loci were screened in 69 individuals from two alpine populations in Austria. Allelic variation was high with nine to 37 alleles per locus and expected heterozygosities ranging from 0.37 to 0.95. The high level of polymorphism revealed by these loci will be relevant for population studies in context to the evolutionary history of this species.
