131,107 research outputs found
The Fire salamander: source for new species
No full textSteinfartz S, Tautz D. The Fire salamander: source for new species. German Research. 2003;(2):14-16
Von Feuersalamandern und neuen Arten
No full textSteinfartz S, Tautz D. Von Feuersalamandern und neuen Arten. Forschung. 2003;(2):16-18
Vor unserer Haustür entstehen neue Arten - Der Feursalamander als ein natürliches Modell der sympatrischen Artbildung.
No full textTautz D, Steinfartz S. Vor unserer Haustür entstehen neue Arten - Der Feursalamander als ein natürliches Modell der sympatrischen Artbildung. Praxis der Naturwissenschaften - Biologie in der Schule. 2002;51(7):3-8
House mouse colonization patterns on the sub-Antarctic Kerguelen Archipelago suggest singular primary invasions and resilience against re-invasion.
Full text linkStarting from Western Europe, the house mouse (Mus musculus domesticus) has spread across the globe in historic times. However, most oceanic islands were colonized by mice only within the past 300 years. This makes them an excellent model for studying the evolutionary processes during early stages of new colonization. We have focused here on the Kerguelen Archipelago, located within the sub-Antarctic area and compare the patterns with samples from other Southern Ocean islands
Development of new microsatellite loci and evaluation of loci from other pinniped species for the Galapagos sea lion (Zalophus californianus wollebaeki)
No full textWolf JBW, Tautz D, Caccone A, Steinfartz S. Development of new microsatellite loci and evaluation of loci from other pinniped species for the Galapagos sea lion (Zalophus californianus wollebaeki). CONSERVATION GENETICS. 2006;7(3):461-465
Tracing early stages of species differentiation: Ecological, morphological and genetic divergence of Galapagos sea lion populations
Full text linkBackground: Oceans are high gene flow environments that are traditionally believed to hamper the build-up of genetic divergence. Despite this, divergence appears to occur occasionally at surprisingly small scales. The Galápagos archipelago provides an ideal opportunity to examine the evolutionary processes of local divergence in an isolated marine environment. Galápagos sea lions (Zalophus wollebaeki) are top predators in this unique setting and have an essentially unlimited dispersal capacity across the entire species range. In theory, this should oppose any genetic differentiation. Results: We find significant ecological, morphological and genetic divergence between the western colonies and colonies from the central region of the archipelago that are exposed to different ecological conditions. Stable isotope analyses indicate that western animals use different food sources than those from the central area. This is likely due to niche partitioning with the second Galápagos eared seal species, the Galápagos fur seal (Arctocephalus galapagoensis) that exclusively dwells in the west. Stable isotope patterns correlate with significant differences in foraging-related skull morphology. Analyses of mitochondrial sequences as well as microsatellites reveal signs of initial genetic differentiation. Conclusion: Our results suggest a key role of intra- as well as inter-specific niche segregation in the evolution of genetic structure among populations of a highly mobile species under conditions of free movement. Given the monophyletic arrival of the sea lions on the archipelago, our study challenges the view that geographical barriers are strictly needed for the build-up of genetic divergence. The study further raises the interesting prospect that in social, colonially breeding mammals additional forces, such as social structure or feeding traditions, might bear on the genetic partitioning of populations
Isolation and characterization of polymorphic tetranucleotide microsatellite loci in the Fire salamander Salamandra salamandra (Amphibia : Caudata)
No full textSteinfartz S, Kusters D, Tautz D. Isolation and characterization of polymorphic tetranucleotide microsatellite loci in the Fire salamander Salamandra salamandra (Amphibia : Caudata). Molecular Ecology Notes. 2004;4(4):626-628.Ten tetranucleotide and one dinucleotide polymorphic microsatellite loci were cloned and characterized for the Fire salamander (Salamandra salamandra) from 34 populations in Germany. A high genetic diversity (5-22 alleles per locus) and heterozygosity (40.6-95.2%) were observed for these markers. Chord distances for population comparisons of the western evolutionary recolonization lineage in the area near Cologne ranged from 0.139 to 0.366, whereas population comparisons between the western and eastern lineage ranged from 0.541 to 0.670. When compared with classical isolation methods, a sufficient number of polymorphic microsatellites can be obtained for the Fire salamander only from specially enriched sublibraries
Do New Genes Stem From the Non-Coding Part of the Genome During Fast Adaptation Processes?
No full textIt is often thought that evolution is a slow process. During ecological changes in the environment, however, evolution can happen very fast. One of the reasons for this could be the role of new genes that are recruited during that adaptation. DIETHARD TAUTZ pursues the theory that these new genes come out of the so-called non-coding part of the genome. He is interested in studying the fraction of bioactive molecules that come out of random sequences. So far, this explanation has been thought unlikely but, as he explains in this video, synthesizing random sequences and using bacteria as a test system his research group found bioactive molecules in them. This suggests that during fast adaptation processes new genes are recruited from this background of genes in the non-coding part of the genome. This has important implications for our understanding of how adaptation works and offers great potential for the use of these bioactive molecules for medical and pharmaceutical purposes
The genetic population structure of the gray mouse lemur (Microcebus murinus), a basal primate from Madagascar
No full textThe genetic structure of a population is closely connected to fundamental evolutionary processes and aspects of social behavior. Information on genetic structure is therefore instrumental for the interpretation of social behavior and evolutionary reconstructions of social systems. Gray mouse lemurs (Microcebus murinus) are basal primates endemic to Madagascar whose social organization is characterized by solitary foraging at night and communal resting during the day. Conflicting reports about population structure based on behavioral observations led us to examine the genetic structure of one population in detail in order to: (1) identify natural genetic units in this solitary primate, and (2) to test the assumption of current models of primate social evolution that solitary primates are organized in matrilines. DNA was extracted from tissue samples of 85 individuals from Kirindy forest to determine their variability at a 530 bp fragment of the mitochondrial D-loop and at six microsatellite loci. We found that this population was characterized by a great general diversity among mtDNA haplotypes, a pronounced sex difference in mtDNA haplotype diversity and spatial clustering of females with a particular haplotype, but low average relatedness among members of haplotype clusters. Specifically. we identified 13 different haplotypes, which were unevenly distributed among individuals. About 80% of all individuals, most of which were females or juvenile males, shared a single haplotype. Rare haplotypes were almost exclusively represented by single adult males, who apparently migrated into this population. One other haplotype was represented by a small group of females living at one edge of the study area. Microsatellite analysis revealed above-average relatedness among females with overlapping home ranges, as well as no signs of inbreeding, implying that male dispersal results in high levels of gene flow among matrilineal groups. We conclude that gray mouse lemur populations are hierarchically organized in small family units of closely related females that form stable sleeping groups, several of which are connected through a common mtDNA haplotype and form spatially distinct clusters. The presence of such matrilines supports a basic assumption of current models of primate social evolution
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