Bio: Ingrid Seibold is an academic researcher from University of Greifswald. The author has contributed to research in topics: Monophyly & Accipitriformes. The author has an hindex of 10, co-authored 10 publications receiving 857 citations.
TL;DR: A phylogeny reconstructed from nucleotide sequences agrees with one based on song and some morphological characters in identifying P. brehmii as the oldest branch within the chiffchaff group, while the position of P. canariensis with respect to these two clades is uncertain.
Abstract: Nucleotide sequences of the mitochondrial cytochrome b gene (1041 bp), analysis of vocalizations and behavioural evidence from zones of contact were used to reassess the species limits and phylogenetic relationships at the species and subspecies levels in the Phylloscopus collybita complex A new classification is proposed which recognizes four biological species Phylloscopus brehmii (Iberia) and P canariensis (Canary Islands) are genetically and bioacoustically highly distinct There is no mitochondrial gene flow between them or with P collybita The Mountain Chiffchaff P sindianus (with subspecies sindianus and Iorenzii) is equally distinct genetically from southwest Asian subspecies of P collybita (caucasicus, brevirostris) The status of the Siberian form tristis, which shares potentially synapomorphic characters with the Mountain Chiffchaff (ascending song notes, grey-brown adult plumage) but genetically closely resembles P c collybita and P c abietinus, remains uncertain In two zones of secondary contact between taxa with “greenish” (P collybita) and brownish plumage, hybridization is either unrecorded (caucasicus v lorenzii, Caucasus Mountains) or its extent is insufficiently known (abietinus v tristis, west of Ural Mountains) A phylogeny reconstructed from nucleotide sequences agrees with one based on song and some morphological characters in identifying P brehmii as the oldest branch within the chiffchaff group Of the remaining taxa, four fall into a clade with greenish plumage (P collybita ssp), two into one with brownish plumage (P s sindianus, P s lorenzii), while the position of P canariensis with respect to these two clades is uncertain Molecular and phenotypic phylogenies contradict each other regarding the affinities of P (ssp?) tristis
TL;DR: The data suggest that the fraction of the adult population having a hybrid origin (hybrids or backcrosses) is in the order of 10%, consistent with male‐biased gene flow and Haldane’s rule.
Abstract: In the western Pyrenees (Southwest France and Northwest Spain), a narrow hybrid zone exists between the common chiffchaff Phylloscopus (collybita) collybita and the Iberian chiffchaff Phylloscopus (c.) brehmii. In this zone, which is approximately 20 km wide, mixed matings and individuals singing the songs of both taxa occur at substantial frequencies (24 and 8.6%, respectively), suggesting frequent hybridization. Previous studies have shown very weak mitochondrial gene flow (Nm = 0.065), whereas four microsatellites suggested much higher nuclear gene flow (Nm = 4.9). In this study we used the amplified fragment length polymorphism (AFLP) method in order to identify hybrids and early backcrosses. We typed 91 birds from both allopatric and sympatric areas for 12 informative AFLP markers (of > 141 polymorphic fragments), obtained by screening 13 AFLP primer combinations. These individuals were previously typed for song (brehmii, collybita or mixed singers), mitochondrial DNA (mtDNA) haplotype and allelic genotypes at four microsatellite loci. Assignment tests demonstrated that in the zone of sympatry, a substantial number of intermediate genotypes existed among the birds previously believed to be pure collybita and brehmii, based on song and mtDNA haplotype. The majority of the mixed singers had intermediate genotypes. Our data suggest that the fraction of the adult population having a hybrid origin (hybrids or backcrosses) is in the order of 10%. With such a frequency of genetic hybrids, there would have been much more mtDNA introgression than observed, had female hybrids been perfectly fertile/viable. This result is consistent with male-biased gene flow and Haldane's rule.
TL;DR: Phylogenetic relationships of the reed warbler group and their potential relatives were studied using nucleotide sequences of the mitochondrial cytochrome b gene to resolve phylogenetically young relationships quite well, whereas more ancient nodes remained poorly resolved.
Abstract: Phylogenetic relationships of the reed warbler group (generaAcrocephalus, Hippolais, Chloropeta;Aves: Passeriformes) and their potential relatives were studied using nucleotide sequences (1 kb) of the mitochondrial cytochromebgene. This species-rich but morphologically poorly differentiated group of insectivorous passerines is distributed in Eurasia, Africa, and Australasia. Intergeneric relationships were poorly resolved, but monophyly of the reed warbler group (includingChloropeta) versus other Sylviidae was strongly supported. A basal polytomy within the reed warbler group consists of seven branches and may indicate a rapid early radiation. In the genusAcrocephalusthree major clades were identified, which corresponded to phenotypic groups characterized by body size and plumage patterns. However, current delimitation of some subgenera (Acrocephalus, Lusciniola, Bebrornis) is at variance with our phylogeny estimate, and appropriate revisions are proposed. The genusHippolais,which may or may not be monophyletic, consisted of two well-supported clades of four species each. SomeAcrocephalustaxa whose species status had been doubted (griseldis, tangorum, orientalis, australis) proved to be highly distinct genetically. Genetic distances between members of two pairs of allopatricHippolaistaxa (caligata/rama; opaca/elaeica) were as large or larger than between other closely related warbler species. Overall, cytochromebsequences resolved phylogenetically young relationships quite well, whereas more ancient nodes remained poorly resolved.
TL;DR: MtDNA sequence data promise to be very useful in quantifying the genetic differentiation and phylogenetic relationships among closely related species, especially in morphologically poorly differentiated genera like Phylloscopus.
Abstract: The mitochondrial genetic differentiation and molecular phylogenetic relationships of western and eastern Bonelli's Warblers (Phylloscopus b. bonelli, P. b. orientalis) and Green Warbler Phylloscopus nitidus were investigated. The cytochrome b gene was amplified by polymerase chain reaction and 1038 nucleotides were sequenced directly in these and several other Phylloscopus species plus Sylvia atricapilla and Acrocephalus scirpaceus. The mitochondrial genetic distance between eastern and western Bonelli's Warblers was as large (8.3-8.6%) as between each of them and the Wood Warbler P. sibilatrix. Compared to the amount of mtDNA differentiation between other closely related species and subspecies of birds, the divergence between the Bonelli's warblers is far greater than among typical subspecies. Together with the distinct differences in calls and structure of song elements the genetic data support full species status of the two taxa. The cytochrome b sequence of P. nitidus differed by 2.5-3.1% from P. trochiloides, to which it is most closely related. This divergence is also larger than between most subspecies of birds studied so far at this locus and is consistent with the placement of P. nitidus as an allospecies within the superspecies P. [trochiloides]. We discuss population-genetic scenarios for a potentially accelerated rate of mtDNA differentiation in relatively small, geographically isolated populations that might help to explain the large sequence divergence observed. A phylogenetic tree was constructed by maximum parsimony and neighbour-joining. Chiffchaff P. collybita and Willow Warbler P. trochilus are sister species and together form the sister group of Bonelli's and Wood Warblers. As expected, Arctic Warbler P. borealis was found to be the sister species of the Greenish Warbler complex (including nitidus), whereas the relationships of P. (inornatus) humei relative to the other species could not be resolved. Among the taxa studied, those without wing-bars belong to a phylogenetically older clade than those with wing-bars. MtDNA sequence data promise to be very useful in quantifying the genetic differentiation and phylogenetic relationships among closely related species, especially in morphologically poorly differentiated genera like Phylloscopus.
TL;DR: There is a strong, but incomplete, reproductive barrier between two morphologically very similar Chiffchaff taxa in SW France and northern Spain, indicating strong selection against hybrids.
Abstract: Mating pattern and gene flow were studied in the contact zone between two morphologically very similar Chiffchaff taxa (Phylloscopus collybita, P. brehmii) in SW France and northern Spain. Mating was assortative in brehmii, but not in collybita. Mixed matings were strongly asymmetric (excess of callybita male x brehmii female pairs), but did produce viable offspring in some cases. Sequence divergence of the mitochondrial cytochrome b gene was 4.6%; Haplotypes segregated significantly with phenotype (only five 'mismatches' among 94 individuals), demonstrating that mitochondrial gene flow was very restricted. The estimated proportion of F-1 hybrids in the reproductive population was significantly lower than expected under a closed population model, indicating strong selection against hybrids. Genetic typing of 101 individuals at four microsatellite loci also showed significant population differentiation, but nuclear gene flow was estimated to be 75 times higher than mitochondrial gene flow. This strong discrepancy is probably due to unisexual hybrid sterility (Haldane's rule). Thus, there is a strong, but incomplete, reproductive barrier between these taxa. (Less)
TL;DR: New advances in satellite telemetry, genetic analyses and stable isotope chemistry are now making it possible to determine the population and geographical origin of individual birds, and the relevance of understanding migratory connectivity to ecological, evolutionary and conservation issues is considered.
Abstract: Migration is the regular seasonal movement of animals from one place to another, often from a breeding site to a nonbreeding site and back. Because the act of migration makes it difficult to follow individuals and populations year round, our understanding of the ecology and evolution of migrating organisms, particularly birds, has been severely impeded. Exciting new advances in satellite telemetry, genetic analyses and stable isotope chemistry are now making it possible to determine the population and geographical origin of individual birds. Here, we review these new approaches and consider the relevance of understanding migratory connectivity to ecological, evolutionary and conservation issues.
TL;DR: In this article, the authors present a review of known cases of mito-nuclear discordance in animal systems and summarize the biogeographic patterns in each instance and identify common drivers of discordance.
Abstract: Combining nuclear (nuDNA) and mitochondrial DNA (mtDNA) markers has improved the power of molecular data to test phylogenetic and phylogeographic hypotheses and has highlighted the limitations of studies using only mtDNA markers. In fact, in the past decade, many conflicting geographic patterns between mitochondrial and nuclear genetic markers have been identified (i.e. mito-nuclear discordance). Our goals in this synthesis are to: (i) review known cases of mito-nuclear discordance in animal systems, (ii) to summarize the biogeographic patterns in each instance and (iii) to identify common drivers of discordance in various groups. In total, we identified 126 cases in animal systems with strong evidence of discordance between the biogeographic patterns obtained from mitochondrial DNA and those observed in the nuclear genome. In most cases, these patterns are attributed to adaptive introgression of mtDNA, demographic disparities and sex-biased asymmetries, with some studies also implicating hybrid zone movement, human introductions and Wolbachia infection in insects. We also discuss situations where divergent mtDNA clades seem to have arisen in the absence of geographic isolation. For those cases where foreign mtDNA haplotypes are found deep within the range of a second taxon, data suggest that those mtDNA haplotypes are more likely to be at a high frequency and are commonly driven by sex-biased asymmetries and/or adaptive introgression. In addition, we discuss the problems with inferring the processes causing discordance from biogeographic patterns that are common in many studies. In many cases, authors presented more than one explanation for discordant patterns in a given system, which indicates that likely more data are required. Ideally, to resolve this issue, we see important future work shifting focus from documenting the prevalence of mito-nuclear discordance towards testing hypotheses regarding the drivers of discordance. Indeed, there is great potential for certain cases of mitochondrial introgression to become important natural systems within which to test the effect of different mitochondrial genotypes on whole-animal phenotypes.
TL;DR: A global map of zoogeographic regions is generated by combining data on the distributions and phylogenetic relationships of 21,037 species of amphibians, birds, and mammals, and it is shown that spatial turnover in the phylogenetic composition of vertebrate assemblages is higher in the Southern than in the Northern Hemisphere.
Abstract: Modern attempts to produce biogeographic maps focus on the distribution of species, and the maps are typically drawn without phylogenetic considerations. Here, we generate a global map of zoogeographic regions by combining data on the distributions and phylogenetic relationships of 21,037 species of amphibians, birds, and mammals. We identify 20 distinct zoogeographic regions, which are grouped into 11 larger realms. We document the lack of support for several regions previously defined based on distributional data and show that spatial turnover in the phylogenetic composition of vertebrate assemblages is higher in the Southern than in the Northern Hemisphere. We further show that the integration of phylogenetic information provides valuable insight on historical relationships among regions, permitting the identification of evolutionarily unique regions of the world.
TL;DR: It is concluded that reinforcement has probably not been looked for where it is most likely to occur, and many further areas of study are pinpointed that may ultimately provide a strong assessment of the importance of reinforcement in speciation.
Abstract: ▪ Abstract To assess the frequency and importance of reinforcement in nature we must begin by looking for its signature in the most likely places. Theoretical studies can pinpoint conditions that favor and inhibit reinforcement, and empirical studies can identify both how often these conditions occur and whether reinforcement results. We examine how well these tools have addressed these questions by searching for gaps and mismatches in theoretical and empirical studies of reinforcement. We concentrate on five areas: (a) a broad assessment of selection against interspecific mating, (b) the mode and genetic basis of nonrandom mating, (c) the geography of speciation, (d) divergent selection on mating cues, (e) and the genetics of reproductive isolation. We conclude that reinforcement has probably not been looked for where it is most likely to occur. We pinpoint however, many further areas of study that may ultimately provide a strong assessment of the importance of reinforcement in speciation. “The grossest ...
TL;DR: A review of the recent literature on birds reveals the existence of relatively few cases in which nuclear markers contradict mitochondrial markers in a fashion not consistent with coalescent theory as mentioned in this paper, but such cases do not contradict the mtDNA inference of recent isolation and evolutionary divergence.
Abstract: Mitochondrial DNA (mtDNA) has been the workhorse of research in phylogeography for almost two decades. However, concerns with basing evolutionary interpretations on mtDNA results alone have been voiced since the inception of such studies. Recently, some authors have suggested that the potential problems with mtDNA are so great that inferences about population structure and species limits are unwarranted unless corroborated by other evidence, usually in the form of nuclear gene data. Here we review the relative merits of mitochondrial and nuclear phylogeographical studies, using birds as an exemplar class of organisms. A review of population demographic and genetic theory indicates that mitochondrial and nuclear phylogeographical results ought to concur for both geographically unstructured populations and for populations that have long histories of isolation. However, a relatively common occurrence will be shallow, but geographically structured mtDNA trees--without nuclear gene corroboration--for populations with relatively shorter periods of isolation. This is expected because of the longer coalescence times of nuclear genes (approximately four times that of mtDNA); such cases do not contradict the mtDNA inference of recent isolation and evolutionary divergence. Rather, the nuclear markers are more lagging indicators of changes in population structure. A review of the recent literature on birds reveals the existence of relatively few cases in which nuclear markers contradict mitochondrial markers in a fashion not consistent with coalescent theory. Preliminary information from nuclear genes suggests that mtDNA patterns will prove to be robust indicators of patterns of population history and species limits. At equilibrium, mitochondrial loci are generally a more sensitive indicator of population structure than are nuclear loci, and mitochondrial estimates of F(ST)-like statistics are generally expected to exceed nuclear ones. Hence, invoking behavioural or ecological explanations of such differences is not parsimonious. Nuclear genes will prove important for quantitative estimates of the depths of haplotype trees, rates of population growth and values of gene flow.