| 121. |
- Price, T. D., et al.
(författare)
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Niche filling slows the diversification of Himalayan songbirds
- 2014
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 509:7499, s. 222- +
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Tidskriftsartikel (refereegranskat)abstract
- Speciation generally involves a three-step process-range expansion, range fragmentation and the development of reproductive isolation between spatially separated populations(1,2). Speciation relies on cycling through these three steps and each may limit the rate at which new species form(1,3). We estimate phylogenetic relationships among all Himalayan songbirds to ask whether the development of reproductive isolation and ecological competition, both factors that limit range expansions(4), set an ultimate limit on speciation. Based on a phylogeny for all 358 species distributed along the eastern elevational gradient, here we show that body size and shape differences evolved early in the radiation, with the elevational band occupied by a species evolving later. These results are consistent with competition for niche space limiting species accumulation(5). Even the elevation dimension seems to be approaching ecological saturation, because the closest relatives both inside the assemblage and elsewhere in the Himalayas are on average separated by more than five million years, which is longer than it generally takes for reproductive isolation to be completed(2,3,6); also, elevational distributions are well explained by resource availability, notably the abundance of arthropods, and not by differences in diversification rates in different elevational zones. Our results imply that speciation rate is ultimately set by niche filling(that is, ecological competition for resources), rather than by the rate of acquisition of reproductive isolation.
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| 122. |
- Rancilhac, Loïs, et al.
(författare)
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Introgression Underlies Phylogenetic Uncertainty But Not Parallel Plumage Evolution in a Recent Songbird Radiation
- 2023
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Ingår i: Systematic Biology. - : Oxford University Press. - 1063-5157 .- 1076-836X.
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Tidskriftsartikel (refereegranskat)abstract
- Instances of parallel phenotypic evolution offer great opportunities to understand the evolutionary processes underlying phenotypic changes. However, confirming parallel phenotypic evolution and studying its causes requires a robust phylogenetic framework. One such example is the “black-and-white wagtails,” a group of 5 species in the songbird genus Motacilla: 1 species, Motacilla alba, shows wide intra-specific plumage variation, while the 4r others form 2 pairs of very similar-looking species (M. aguimp + M. samveasnae and M. grandis + M. maderaspatensis, respectively). However, the 2 species in each of these pairs were not recovered as sisters in previous phylogenetic inferences. Their relationships varied depending on the markers used, suggesting that gene tree heterogeneity might have hampered accurate phylogenetic inference. Here, we use whole genome resequencing data to explore the phylogenetic relationships within this group, with a special emphasis on characterizing the extent of gene tree heterogeneity and its underlying causes. We first used multispecies coalescent methods to generate a “complete evidence” phylogenetic hypothesis based on genome-wide variants, while accounting for incomplete lineage sorting (ILS) and introgression. We then investigated the variation in phylogenetic signal across the genome to quantify the extent of discordance across genomic regions and test its underlying causes. We found that wagtail genomes are mosaics of regions supporting variable genealogies, because of ILS and inter-specific introgression. The most common topology across the genome, supporting M. alba and M. aguimp as sister species, appears to be influenced by ancient introgression. Additionally, we inferred another ancient introgression event, between M. alba and M. grandis. By combining results from multiple analyses, we propose a phylogenetic network for the black-and-white wagtails that confirms that similar phenotypes evolved in non-sister lineages, supporting parallel plumage evolution. Furthermore, the inferred reticulations do not connect species with similar plumage coloration, suggesting that introgression does not underlie parallel plumage evolution in this group. Our results demonstrate the importance of investing genome-wide patterns of gene tree heterogeneity to help understand the mechanisms underlying phenotypic evolution. [Gene tree heterogeneity; incomplete lineage sorting; introgression; parallel evolution; phylogenomics; plumage evolution; wagtails.]
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| 123. |
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| 124. |
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| 125. |
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| 126. |
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| 127. |
- Sangster, George, 1970-, et al.
(författare)
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Multi-locus phylogenetic analysis of Old World chats and flycatchers reveals extensive paraphyly at family, subfamily and genus level (Aves: Muscicapidae).
- 2010
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 57, s. 380-392
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Tidskriftsartikel (refereegranskat)abstract
- The chats and flycatchers (Muscicapidae) represent an assemblage of 275 species in 48 genera. Defining natural groups within this assemblage has been challenging because of its high diversity and a paucity of phylogenetically informative morphological characters. We assessed the phylogenetic relationships of 118 species and 34 genera of Muscicapidae, and 20 species of Turdidae, using molecular sequence data from one mitochondrial gene and three nuclear loci, in total 3240 bp. Bayesian and maximum likelihood analyses yielded a well-resolved tree in which nearly all basal nodes were strongly supported. The traditionally defined Muscicapidae, Muscicapinae and Saxicolinae were paraphyletic. Four major clades are recognized in Muscicapidae: Muscicapinae, Niltavinae (new family-group name), Erithacinae and Saxicolinae. Interesting relationships recovered by this analysis include: (i) a clade comprising the ‘blue’ flycatcher genera Niltava, Cyornis, Cyanoptila and Eumyias and some species of Rhinomyias; (ii) the position of Erithacus rubecula in a clade of otherwise exclusively African species; (iii) a close relationship between the shortwing Heinrichia calligyna and the flycatcher Rhinomyias insignis; (iv) a sister relationship between forktails Enicurus and whistling thrushes Myophonus; and (v) a sister relationship of Ficedula and the ‘chats’ Monticola, Phoenicurus, Saxicola and Oenanthe. A high number of traditionally defined genera was found to be paraphyletic or polyphyletic. Taxonomic implications are discussed.
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| 128. |
- Sangster, G., et al.
(författare)
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Niltavinae, a new taxon of Old World flycatchers (Aves: Muscicapidae)
- 2016
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Ingår i: Zootaxa. - : Magnolia Press. - 1175-5326 .- 1175-5334. ; 4196:3, s. 428-429
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Tidskriftsartikel (refereegranskat)abstract
- The relationships among Old World chats and flycatchers (Muscicapidae) have recently been clarified in two independent molecular phylogenetic studies (Sangster et al. 2010, Zuccon & Ericson 2010). Both studies recovered a well-supported clade of predominantly blue flycatchers of the genera Niltava, Cyornis, Eumyias and Cyanoptila, some species traditionally included in the genus Rhinomyias and one species traditionally included in Ficedula (F. monileger). The family-group name Niltavinae Sangster, Alström, Forsmark & Olsson, 2010, was introduced for this clade (Sangster et al. 2010). Unfortunately, our description of the new taxon Niltavinae did not include a diagnosis (sensu ICZN article 13.1.1) and thus inadvertently made this name unavailable for nomenclatural purposes (Zuccon 2011). The supplementary data associated with our original paper included evidence by which the taxon Niltavinae can be diagnosed: a 1 base pair (bp) deletion in the ornithine decarboxylase gene, as shown in Figure S1 in the online version (doi:10.1016/j.ympev.2010.07.008), but this was not mentioned in the printed version of our paper. Given that Niltavinae Sangster, Alström, Forsmark & Olsson, 2010 represents a nomen nudum, and the clade for which this name was intended thus remains unnamed, we here provide the following description.
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| 129. |
- Semenov, Georgy A., et al.
(författare)
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Asymmetric introgression reveals the genetic architecture of a plumage trait
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide variation in introgression rates across hybrid zones offers a powerful opportunity for studying population differentiation. One poorly understood pattern of introgression is the geographic displacement of a trait implicated in lineage divergence from genome-wide population boundaries. While difficult to interpret, this pattern can facilitate the dissection of trait genetic architecture because traits become uncoupled from their ancestral genomic background. We studied an example of trait displacement generated by the introgression of head plumage coloration from personata to alba subspecies of the white wagtail. A previous study of their hybrid zone in Siberia revealed that the geographic transition in this sexual signal that mediates assortative mating was offset from other traits and genetic markers. Here we show that head plumage is associated with two small genetic regions. Despite having a simple genetic architecture, head plumage inheritance is consistent with partial dominance and epistasis, which could contribute to its asymmetric introgression. Hybrid zones are windows into the evolutionary process. Semenov et al. find that the head plumage differences between white wagtail subspecies have a simple genetic basis involving two small genetic regions, in which partially dominant and epistatic interactions help to explain how this sexual signal has become decoupled from other plumage traits.
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| 130. |
- Singh, Ashutosh, et al.
(författare)
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Taxonomy of cryptic species in theCyornis rubeculoidescomplex in the Indian subcontinent
- 2020
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Ingår i: Ibis. - : WILEY. - 0019-1019 .- 1474-919X. ; 162:3, s. 924-935
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Tidskriftsartikel (refereegranskat)abstract
- Taxa classified as subspecies may in fact be cryptic species. We assessed the taxonomic status of the Blue-throated FlycatcherCyornis rubeculoidescomplex in India, which consists of several forms with similar plumages and song. We used mitochondrial and nuclearDNA, plumage traits, and detailed song analysis to ascertain the taxonomic status of the different forms. The molecular data identified three primary clades: (1) in the west Himalayan foothills, (2) at higher elevations in the northeast hill states of Meghalaya, Nagaland and Mizoram, and (3) at lower elevations in the northeastern hills of Meghalaya and the east Himalayas of Arunachal Pradesh. The western clade represents nominateC. rubeculoides rubeculoides. The high-elevation eastern clade was considered to beC. rubeculoides rogersi, because it included a sample from this subspecies from near the type locality in southwest Myanmar. These two sister clades had an estimated divergence time of 1.5 million years (my). The low-elevation east clade has previously been assigned toC. rubeculoides, but we showed it is closely related to the Hainan Blue FlycatcherCyornis hainanus, formerly thought to breed only further east, with an estimated divergence time of only ~0.8 my. This clade may represent a subspecies ofC. hainanusor, given reports of widespread sympatry withC. hainanusin Thailand, a distinct species,Cyornis dialilaemus. However, more research is advocated, including molecular data, from the area of overlap. Songs were remarkably similar across all taxa. In playback experiments,C. r. rubeculoidesin the west responded to all taxa. This is in agreement with recent work demonstrating that song differences and responses to songs are not always a good indicator of the progress of reproductive isolation.
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