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71.
Jons A. Aguirre‐Liguori Brandon S. Gaut Juan Pablo Jaramillo‐Correa Maud I. Tenaillon Salvador Montes‐Hernndez Felipe García‐Oliva Sarah J. Hearne Luis E. Eguiarte 《Molecular ecology》2019,28(11):2814-2830
Patterns of genomic divergence between hybridizing taxa can be heterogeneous along the genome. Both differential introgression and local adaptation may contribute to this pattern. Here, we analysed two teosinte subspecies, Zea mays ssp. parviglumis and ssp. mexicana, to test whether their divergence has occurred in the face of gene flow and to infer which environmental variables have been important drivers of their ecological differentiation. We generated 9,780 DArTseqTM SNPs for 47 populations, and used an additional data set containing 33,454 MaizeSNP50 SNPs for 49 populations. With these data, we inferred features of demographic history and performed genome wide scans to determine the number of outlier SNPs associated with climate and soil variables. The two data sets indicate that divergence has occurred or been maintained despite continuous gene flow and/or secondary contact. Most of the significant SNP associations were to temperature and to phosphorus concentration in the soil. A large proportion of these candidate SNPs were located in regions of high differentiation that had been identified previously as putative inversions. We therefore propose that genomic differentiation in teosintes has occurred by a process of adaptive divergence, with putative inversions contributing to reduced gene flow between locally adapted populations. 相似文献
72.
Pablo D. Lavinia Ana S. Barreira Leonardo Campagna Pablo L. Tubaro Darío A. Lijtmaer 《Molecular ecology》2019,28(7):1730-1747
Avian diversity in the Neotropics has been traditionally attributed to the effect of vicariant forces promoting speciation in allopatry. Recent studies have shown that phylogeographical patterns shared among codistributed species cannot be explained by a single vicariant event, as species responses to a common barrier depend on the biological attributes of each taxon. The open vegetation corridor (OVC) isolates Amazonia and the Andean forests from the Atlantic Forest, creating a notorious pattern of avian taxa that are disjunctly codistributed in these forests. Here, we studied and compared the evolutionary histories of Ramphotrigon megacephalum and Pipraeidea melanonota, two passerines with allopatric populations east and west of the OVC that represent different subspecies. These species differ in their biological attributes: R. megacephalum is a sedentary, forest specialist mostly confined to bamboo understorey, whereas P. melanonota is a seasonal migrant and generalist species that ranges in a variety of closed and semi‐open environments. We performed genetic and genomic analyses, complemented with the study of coloration and behavioural differentiation, to assess population divergence across the OVC. We found that the evolutionary histories of both R. megacephalum and P. melanonota have been shaped by this environmental barrier. However, these species responded in different and asynchronous manners to the establishment of the OVC and to past connections between the currently isolated South American forests, which can be mostly explained by their distinct ecologies and dispersal abilities. Our results support the fact that the biological attributes of species can make their evolutionary histories idiosyncratic. 相似文献
73.
Plant Ecology - Few studies have quantified changes in riparian and adjacent forest across landscape units. In this study, the composition and structure of riparian and adjacent forest were... 相似文献
74.
Dánae Cabrera-Toledo Jorge González-Astorga Andrew P. Vovides Alejandro Casas Ofelia Vargas-Ponce Pablo Carrillo-Reyes Janet Nolasco-Soto Ernesto Vega 《Population Ecology》2019,61(1):62-73
Ecological and microevolutionary perspectives were used to investigate signs of background extinction in two endemic species. We studied relict populations of the cycad Dioon caputoi, contrasting its population structure and neighborhood size with those of Dioon planifolium as a demographically healthier reference population. Population dynamics analysis was performed on two populations of D. caputoi through Integral Projection Models and genetic neighborhoods compared between species through 172 Inter Simple Sequence Repeat loci performed in one population of each of the two study species. The D. caputoi populations mostly comprised adult plants, while D. planifolium presented mainly juvenile individuals. Dioon caputoi showed equilibrium in population growth (i.e., λ ≈ 1), with low recruitment, and its genetic neighborhood revealed highly related individuals in a unique distance class (rij = 0.407, 33 m). A contrasting pattern was found in D. planifolium, which showed higher relatedness in the first distance class (rij = 0.543, 5 m), gradually decreasing to 20 m. The discrepancies between the two species reflect different strategies of persistence. Dioon caputoi conserves a relict dynamics with signs of a multigenerational, attritional loss of reproductive fitness, while D. planifolium does not. This study furthers our understanding of the background extinction process and the information will thus contribute to the management and conservation of this endangered species. 相似文献
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76.
Andrea A. Villanueva Sofía Puvogel Pablo Lois Ernesto Muñoz-Palma Manuel Ramírez Orellana Fabiana Lubieniecki 《Cell Adhesion & Migration》2019,13(1):33-40
Neuroblastoma (NB) is the most common pediatric extracranial solid tumor. It arises during development of the sympathetic nervous system. Netrin-4 (NTN4), a laminin-related protein, has been proposed as a key factor to target NB metastasis, although there is controversy about its function. Here, we show that NTN4 is broadly expressed in tumor, stroma and blood vessels of NB patient samples. Furthermore, NTN4 was shown to act as a cell adhesion molecule required for the migration induced by Neogenin-1 (NEO1) in SK-N-SH neuroblastoma cells. Therefore, we propose that NTN4, by forming a ternary complex with Laminin γ1 (LMγ1) and NEO1, acts as an essential extracellular matrix component, which induces the migration of SK-N-SH cells. 相似文献
77.
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79.
Chavarría T Valenciano AI Mayordomo R Egea J Comella JX Hallböök F de Pablo F de la Rosa EJ 《Developmental neurobiology》2007,67(13):1777-1788
Programmed cell death is a genuine developmental process of the nervous system, affecting not only projecting neurons but also proliferative neuroepithelial cells and young neuroblasts. The embryonic chick retina has been employed to correlate in vivo and in vitro studies on cell death regulation. We characterize here the role of two major signaling pathways, PI3K-Akt and MEK-ERK, in controlled retinal organotypic cultures from embryonic day 5 (E5) and E9, when cell death preferentially affects proliferating neuroepithelial cells and ganglion cell neurons, respectively. The relative density of programmed cell death in vivo was much higher in the proliferative and early neurogenic stages of retinal development (E3-E5) than during neuronal maturation and synaptogenesis (E8-E19). In organotypic cultures from E5 and E9 retinas, insulin, as the only growth factor added, was able to completely prevent cell death induced by growth factor deprivation. Insulin activated both the PI3K-Akt and the MEK-ERK pathways. Insulin survival effect, however, was differentially blocked at the two stages. At E5, the effect was blocked by MEK inhibitors, whereas at E9 it was blocked by PI3K inhibitors. The cells which were found to be dependent on insulin activation of the MEK-ERK pathway at E5 were mostly proliferative neuroepithelial cells. These observations support a remarkable specificity in the regulation of early neural cell death. 相似文献
80.
Sonia Cristina Zapata Alejandro Travaini Pablo Ferreras Miguel Delibes 《European Journal of Wildlife Research》2007,53(4):276-286
We evaluated the existence of trophic guild structure, considering seasonal and annual variation, in two terrestrial carnivore assemblages: one from Santa Cruz province (Argentinean Patagonia, composed by six carnivore species), and the other from Doñana National Park (SW Spain, composed by five carnivore species). To identify trophic guilds, we first studied seasonal and annual diets of predators, calculated trophic overlap among species pairs, and then constructed overlap matrices (similarity matrices). We determined guild membership objectively by entering the similarity matrices into the clustering technique unweighted pair-group method with arithmetic averaging. Carnivores from both assemblages were grouped, respectively, into four feeding guilds. Lagomorphs and rodents promoted the formation of two feeding guilds in both study sites, although the taxonomic composition of predator species that composed them was different. The ungulates-edentates feeding guild was only present at Santa Cruz, whereas the birds and reptiles feeding guild was only present at Doñana. Invertebrates and fruits were the base for the formation of a guild composed by species of the same taxonomic origin both in Santa Cruz and Doñana. Guild structure of Santa Cruz and Doñana assemblages did not exhibit seasonal or annual variation, although the specific guild composition changed over the two studied periods for both assemblages. This structure probably responded to discontinuities in resource spectra in Santa Cruz and fluctuations in rabbit abundance in Doñana. Our results support the hypothesis that establishes that guilds are originated by opportunistic convergence of species on abundant and energetically rewarding resources. 相似文献