RESUMO
The molecular phylogenies of Cactaceae have enabled us to better understand their systematics, biogeography, and diversification ages. However, most of the phylogenetic relationships within Cactaceae major groups remain unclear, largely due to the lack of an appropriate set of molecular markers to resolve its contentious relationships. Here, we explored the genome and transcriptome assemblies available for Cactaceae and identified putative orthologous regions shared among lineages of the subfamily Cactoideae. Then we developed a probe set, named Cactaceae591, targeting both coding and noncoding nuclear regions for representatives from the subfamilies Pereskioideae, Opuntioideae, and Cactoideae. We also sampled inter- and intraspecific variation to evaluate the potential of this panel to be used in phylogeographic studies. We retrieved on average of 547 orthologous regions per sample. Targeting noncoding nuclear regions showed to be crucial to resolving inter- and intraspecific relationships. Cactaceae591 covers 13 orthologous genes shared with the Angiosperms353 kit and two plastid regions largely used in Cactaceae studies, enabling the phylogenies generated by our panel to be integrated with angiosperm and Cactaceae phylogenies, using these sequences. We highlighted the importance of using coalescent-based species tree approaches on the Cactaceae591 dataset to infer accurate phylogenetic trees in the presence of extensive incomplete lineage sorting in this family.
Assuntos
Cactaceae , Cactaceae/genética , Núcleo Celular/genética , Genoma , Filogenia , Plastídeos/genéticaRESUMO
Genetic introgression among closely related species is a widespread phenomenon across the Tree of Life and could be an important source of adaptive variation during early stages of diversification. In particular, genomic studies have revealed that many rapidly radiating clades tend to have complex, reticulate evolutionary histories. Although rapid radiations appear to be susceptible to introgression, they present special challenges for its detection because formal tests require accurate phylogenies, and paradoxically, introgression itself may obscure evolutionary relationships. To address this methodological challenge, we assessed introgression in a recent, rapid avian radiation in the Andes, the South American siskins (Spinus). Using ~45,000 SNPs, we estimated the Spinus phylogeny using multiple analytical approaches and recovered four strongly conflicting topologies. We performed a series of complimentary introgression tests that included valid tests for each of the likely species trees. From the consilience of test results, we inferred multiple introgression events among Andean Spinus in a way that was robust to phylogenetic uncertainty in the species tree. Positive tests for introgression were corroborated by independent population structure and ancestral assignment analyses, as well as a striking geographic pattern of mitochondrial haplotype sharing among species. The methodological approach we describe could be applied using any genomewide data, including SNP data, for clades without fully resolvable species trees. Our discovery of multiple introgression events within the Andean radiation of Spinus siskins is consistent with an emerging paradigm, that introgression tends to accompany the early stages of diversification.
Assuntos
Evolução Biológica , Tentilhões/classificação , Filogenia , Animais , Genes Mitocondriais , Genética Populacional , Técnicas de Genotipagem , Funções Verossimilhança , Modelos Genéticos , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , América do Sul , IncertezaRESUMO
The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity.
Assuntos
Biodiversidade , Codonopsis/genética , Evolução Biológica , Clima , Mudança Climática , Codonopsis/anatomia & histologia , Codonopsis/efeitos da radiação , Ecologia , Flores/anatomia & histologia , Flores/genética , Flores/efeitos da radiação , Geologia , Filogenia , Polinização , América do SulRESUMO
We review the various proposals of evolutionary and classification schemes for Satyrinae and particularly Euptychiina butterflies, assessing progress and prospects of research for the group. Among the highlights is the proposal to include Morphini, Brassolini and Amathusiini as part of Satyrinae. Although it is clear that this hypothesis requires further investigation, phylogenetic studies recently conducted recover this clade as part of Satyrinae with high support. The phylogenetic analyses for Euptychiina carried out to date recover the monophyly of the group and have identified a variety of genera as non-monophyletic. Further work is necessary to resolve the position of the subtribe and the evolutionary relationships of several genera.