RESUMO
The 'Geophagus' brasiliensis complex is one of the most abundant groups of cichlids from eastern coastal basins in South America. Traditionally, this fish group has been recognized as incertae sedis because of phylogenetic uncertainties and unclear taxonomy. In addition, the remarkable morphological, chromosomal, and DNA variation reported over recent years in several populations of these cichlids has increased the debate about their species richness and their distributional range. Here, we tested the presence of independent evolutionary lineages within the 'G.' brasiliensis complex, addressing their taxonomic status and evolutionary relationships, including a comparative analysis of genetic and morphological patterns, based on an extensive dataset, comprising 172 sampling sites along most of their known range using a mitochondrial marker, RADseq data and geometric morphometrics. The number of putative species in the present study varied from 9 to 11 depending on the molecular species delimitation methods used. Our results revealed at least two putative new taxa ('Geophagus' sp. Doce and 'Geophagus' sp. Upper Contas). Morphometric analyses, particularly those based on Canonical Variate Analysis (CVA), revealed significant morphological differentiation between species within the main clades. On the other hand, analyses of morphological phylogenetic signal and phylomorphospace provided no evidence of adaptive differentiation among these species. Thus, diversification in the 'G.' brasiliensis complex seems to have been influenced by hydrogeological events that promoted allopatry, such as the presence of paleodrainages and distributional reconfiguration through river captures. We propose major changes in the known distribution of some species within the complex and conservatively suggest the recognition of 10 species within the 'Geophagus' brasiliensis complex, with the potential for further dividing 'G.' rufomarginatus after additional taxonomic evaluation.
Assuntos
Evolução Biológica , Ciclídeos/classificação , Animais , Ciclídeos/anatomia & histologia , Ciclídeos/genética , Complexo IV da Cadeia de Transporte de Elétrons/classificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Ligação Genética , Filogenia , Análise de Componente Principal , Subunidades Proteicas/classificação , Subunidades Proteicas/genéticaRESUMO
Deep-sea fishing bycatch enables collection of samples of rare species that are not easily accessible, for research purposes. However, these specimens are often degraded, losing diagnostic morphological characteristics. Several tubes of vestimentiferans, conspicuous annelids endemic to chemosynthetic environments, were obtained from a single batch of deep-sea fishing bycatch at depths of around 1,500 m off Huasco, northern Chile, as part of an ongoing study examining bycatch species. DNA sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene and an intron region within the hemoglobin subunit B2 (hbB2i) were successfully determined using vestimentiferans' dried-up tubes and their degraded inner tissue. Molecular phylogenetic analyses based on DNA sequence identified the samples as Escarpia spicata Jones, 1985, and Lamellibrachia barhami Webb, 1969. These are the southernmost records, vastly extending the geographical ranges of both species from Santa Catalina Island, California to northern Chile for E. spicata (over 8,000 km), and from Vancouver Island Margin to northern Chile for L. barhami (over 10,000 km). We also determined a 16S rRNA sequence of symbiotic bacteria of L. barhami. The sequence of the bacteria is the same as that of E. laminata, Lamellibrachia sp. 1, and Lamellibrachia sp.2 known from the Gulf of Mexico. The present study provides sound evidence forthe presence of reducing environments along the continental margin of northern Chile.
Assuntos
Anelídeos/genética , DNA/química , Animais , Anelídeos/classificação , Anelídeos/microbiologia , Bactérias/genética , Bactérias/isolamento & purificação , Chile , DNA/isolamento & purificação , DNA/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/classificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Hemoglobinas/classificação , Hemoglobinas/genética , Mitocôndrias/genética , Filogenia , Subunidades Proteicas/classificação , Subunidades Proteicas/genética , RNA Ribossômico 16S/química , RNA Ribossômico 16S/isolamento & purificação , RNA Ribossômico 16S/metabolismo , Análise de Sequência de DNA , SimbioseRESUMO
The Tetraodontidae are an Acantomorpha fish family with circumglobal distribution composed of 189 species grouped in 19 genera, occurring in seas, estuaries, and rivers between the tropical and temperate regions. Of these, the genus Colomesus is confined to South America, with what have been up to now considered only two species. C. asellus is spread over the entire Amazon, Tocantins-Araguaia drainages, and coastal environments from the Amazon mouth to Venezuela, and is the only freshwater puffers on that continent. C. psittacus is found in coastal marine and brackish water environments from Cuba to the northern coast of South America as far south as to Sergipe in Brazil. In the present contribution we used morphological data along with molecular systematics techniques to investigate the phylogeny and phylogeography of the freshwater pufferfishes of the genus Colomesus. The molecular part is based on a cytochrome C oxidase subunit I dataset constructed from both previously published and newly determined sequences, obtained from specimens collected from three distinct localities in South America. Our results from both molecular and morphological approaches enable us to identify and describe a new Colomesus species from the Tocantins River. We also discuss aspects of the historical biogeography and phylogeography of the South American freshwater pufferfishes, suggesting that it could be more recent than previously expected.
Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/classificação , Filogenia , Subunidades Proteicas/classificação , Tetraodontiformes/classificação , Animais , Brasil , Complexo IV da Cadeia de Transporte de Elétrons/genética , Variação Genética , Peru , Filogeografia , Subunidades Proteicas/genética , Rios , Análise de Sequência de DNA , Especificidade da Espécie , Tetraodontiformes/anatomia & histologia , Tetraodontiformes/genéticaRESUMO
BACKGROUND: The orderly progression through mitosis is regulated by the Anaphase-Promoting Complex (APC), a large multiprotein E3 ubiquitin ligase that targets key cell-cycle regulators for destruction by the 26 S proteasome. The APC is composed of at least 11 subunits and associates with additional regulatory activators during mitosis and interphase cycles. Despite extensive research on APC and activator functions in the cell cycle, only a few components have been functionally characterized in plants. RESULTS: Here, we describe an in-depth search for APC subunits and activator genes in the Arabidopsis, rice and poplar genomes. Also, searches in other genomes that are not completely sequenced were performed. Phylogenetic analyses indicate that some APC subunits and activator genes have experienced gene duplication events in plants, in contrast to animals. Expression patterns of paralog subunits and activators in rice could indicate that this duplication, rather than complete redundancy, could reflect initial specialization steps. The absence of subunit APC7 from the genome of some green algae species and as well as from early metazoan lineages, could mean that APC7 is not required for APC function in unicellular organisms and it may be a result of duplication of another tetratricopeptide (TPR) subunit. Analyses of TPR evolution suggest that duplications of subunits started from the central domains. CONCLUSIONS: The increased complexity of the APC gene structure, tied to the diversification of expression paths, suggests that land plants developed sophisticated mechanisms of APC regulation to cope with the sedentary life style and its associated environmental exposures.