Términos relacionados

8 resultados encontrados para: AUTOR: Castellanos Morales, Gabriela
  • «
  • 1 de 1
  • »
1.
Artículo
Resumen en: Inglés |
Resumen en inglés

Premise: Domestication usually involves local adaptation to environmental conditions. Cucurbita species are a promising model for studying these processes. Cucurbita moschata is the third major crop in the genus because of its economic value and because it displays high landrace diversity, but research about its genetic diversity, population structure, and phylogeography is limited. We aimed at understanding how geography and elevation shape the distribution of genetic diversity in C. moschata landraces in Mexico. Methods: We sampled fruits from 24 localities throughout Mexico. We assessed 11 nuclear microsatellite loci, one mtDNA region, and three cpDNA regions but found no variation in cpDNA. We explored genetic structure with cluster analysis, and phylogeographic relationships with haplotype network analysis. Results: Mitochondrial genetic diversity was high, and nuclear genetic differentiation among localities was intermediate compared to other domesticated Cucurbita. We found high levels of inbreeding. We recovered two mitochondrial lineages: highland (associated with the Trans-Mexican Volcanic Belt) and lowland. Nuclear microsatellites show that localities from the Yucatan Peninsula constitute a well-differentiated group. Conclusions: Mexico is an area of high diversity for C. moschata, and these landraces represent important plant genetic resources. In Mexico this species is characterized by divergence processes linked to an elevational gradient, which could be related to adaptation and may be of value for applications in agriculture. The Isthmus of Tehuantepec may be a partial barrier to gene flow. Morphological variation, agricultural management, and cultural differences may be related to this pattern of genetic structure, but further studies are needed.


2.
Capítulo de libro
Evaluating the hypothesis of pleistocene refugia for mammals in the Cuatro Ciénegas Basin
Gámez Tamariz, Niza (autora) ; Castellanos Morales, Gabriela (autora) ;
Contenido en: Animal diversity and biogeography of the Cuatro Ciénegas Basin Cham, Switzerland : Springer Nature Switzerland AG, 2019 página 203-224 ISBN:3-030-11261-6 :: 978-3-030-11261-5
PDF
Resumen en: Inglés |
Resumen en inglés

The Cuatro Ciénegas Basin (CCB) in the state of Coahuila, Mexico, is a very diverse ecosystem with high endemism of flora and fauna. It is included in the Ramsar list of wetlands and considered as a priority area for conservation by the World Wildlife Fund (WWF). This site is located within the Chihuahuan Desert (CD) in an isolated area surrounded by the Sierra Madre Oriental and Sierra del Carmen. A previous study by Contreras-Balderas et al. (Southwest Nat 52:400–409, 2007) found 39 mammalian species occurring in the CCB Natural Protected Area, 30 of which are widespread. These authors concluded that there has been a long-term environmental stability in the area, based on archaeological records. In addition, the mammalian biota found is an admixture between the biotas from the Chihuahuan Biotic Province and the Tamaulipeca Province. Therefore, the aim of this study is to describe the biogeographic patterns of the mammals that occur in the CCB to determine whether this site was an important area of refuge during the Pleistocene’s climate pulses and to deepen our knowledge of the mammalian biota of the CCB. We obtained ecological niche models (ENMs) and projected them into past environmental conditions, Last Glacial Maximum (LGM) and Last Interglacial (LIG), to determine whether this area could have constituted a refuge area for mammalian species. A review of the phylogeographic studies on these species to determine whether or not the CCB could have been a Pleistocene refuge for mammalian species was also conducted. Accordingly, we expect that species that found refuge in the CCB will show high genetic variation in this area, while species that were not present in the area during the Pleistocene will show lower levels of genetic variation.

Accordingly, we expect that species that found refuge in the CCB will show high genetic variation in this area, while species that were not present in the area during the Pleistocene will show lower levels of genetic variation. According to our results, the CCB was an important area of refuge during Pleistocene climatic changes, specifically over the Sierra la Madera and Sierra San Marcos. Most mammalian species of the CCB are widespread. Results from past ENMs and phylogeographic analyses were consistent, except for five species of rodents, which did not conform to the expected patterns of genetic diversity and changes in their distribution. Most reviewed analyses failed to include an adequate sample size for Mexican populations. Therefore, conducting phylogeographic studies of these mammals in the CD is fundamental for understanding the dynamics that determined its biodiversity.


Resumen en: Inglés |
Resumen en inglés

Twenty-nine DNA regions of plastid origin have been previously identified in the mitochondrial genome of Cucurbita pepo (pumpkin; Cucurbitaceae). Four of these regions harbor homolog sequences of rbcL, matK, rpl20–rps12 and trnL–trnF, which are widely used as molecular markers for phylogenetic and phylogeographic studies. We extracted the mitochondrial copies of these regions based on the mitochondrial genome of C. pepo and, along with published sequences for these plastome markers from 13 Cucurbita taxa, we performed phylogenetic molecular analyses to identify inter-organellar transfer events in the Cucurbita phylogeny and changes in their nucleotide substitution rates. Phylogenetic reconstruction and tree selection tests suggest that rpl20 and rbcL mitochondrial paralogs arose before Cucurbita diversification whereas the mitochondrial matK and trnL–trnF paralogs emerged most probably later, in the mesophytic Cucurbita clade. Nucleotide substitution rates increased one order of magnitude in all the mitochondrial paralogs compared to their original plastid sequences. Additionally, mitochondrial trnL–trnF sequences obtained by PCR from nine Cucurbita taxa revealed higher nucleotide diversity in the mitochondrial than in the plastid copies, likely related to the higher nucleotide substitution rates in the mitochondrial region and loss of functional constraints in its tRNA genes.


4.
Artículo
*Solicítelo con su bibliotecario/a
Tracing back the origin of pumpkins (Cucurbita pepo ssp. pepo L.) in Mexico
Castellanos Morales, Gabriela (autora) ; Ruiz Mondragón, Karen Y. (autora) ; Hernández Rosales, Helena S. (autora) ; Sánchez de la Vega, Guillermo (autor) ; Gámez Tamariz, Niza (autora) ; Aguirre Planter, Erika (autora) ; Montes Hernández, Salvador (autor) ; Lira Saade, Rafael (autor) ; Eguiarte Fruns, Luis Enrique (autor) ;
Disponible en línea
Contenido en: Proceedings of the Royal Society B: Biological Sciences Volumen 286, número 1908 (July 2019), p. 1-9 ISSN: 1471-2954
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Cucurbita pepois an economically important crop, which consists of cultivated C. pepo ssp. pepo, and two wild taxa (C. pepo ssp. fraterna and C. pepo ssp. ovifera). We aimed at understanding the domestication and thediversity of C. pepo in Mexico. We used two chloroplast regions and nine nuclear microsatellite loci to assess the levels of genetic variation and structure for C. pepo ssp. pepo’s landraces sampled in 13 locations in Mexico, five improved varieties, one C. pepo ssp. fraterna population and ornamental C. pepo ssp. ovifera. We tested four hypotheses regarding the origin of C. pepo ssp. pepo’s ancestor through approximate Bayesian computation: C. pepo ssp. ovifera as the ancestor; C. pepo ssp. fraternaas the ancestor; an unknown extinct lineage as the ancestor; and C. pepo ssp. pepo as hybrid from C. pepo ssp. ovifera and C. pepo ssp. fraterna ancestors. Cucurbita pepo ssp. pepo showed high genetic variation and low genetic differentiation. Cucurbita pepo ssp. fraterna and C. pepo ssp. pepo shared two chloroplast haplotypes. The three subspecies were well differentiated for microsatellite loci. Cucurbita pepo ssp. fraterna was probably C. pepo ssp. pepo’s wild ancestor, but subsequent hybridization between taxa complicate defining C. pepo ssp. pepo’s ancestor.


5.
Artículo
Concerted Pleistocene dispersal and genetic differentiation in passerine birds from the Tres Marías Archipelago, Mexico
Ortiz Ramírez, Marco Fabio (autor) ; Sánchez González, Luis Antonio (autor) ; Castellanos Morales, Gabriela (autora) ; Ornelas, Juan Francisco (autor) ; Navarro Sigüenza, Adolfo Gerardo (autor) ;
Disponible en línea
Contenido en: The Auk: Ornithological Advances Vol. 135, no. 3 (July 2018), p. 716-732 ISSN: 1938-4254
PDF PDF
Resumen en: Español | Inglés |
Resumen en español

Debido a su aislamiento geográfico natural y sus biotas relativamente más simples, los estudios de biología evolutiva comúnmente se han centrado en sistemas insulares. En esta contribución, nosotros usamos secuencias de ADN mitocondrial (mtDNA) de cuatro especies de aves paserinas distribuidas en el Archipiélago de las Tres Marías (ATM) y el territorio continental cercano en el occidente de México, y determinamos las relaciones filogenéticas inter e intraespecíficas entre las poblaciones insulares y continentales, estimamos el tiempo de divergencia en las poblaciones insulares basadas en calibraciones de la edad de las islas, y usamos análisis Bayesianos para probar la historia de colonización de las islas. Específicamente, probamos si esas cuatro especies de aves paserinas del ATM comparten la misma historia de colonización desde que emergieron las islas hace alrededor de 120 mil años, aprovechando la reducción del aislamiento debido a las fluctuaciones del nivel del mar durante el Pleistoceno, o si fueron eventos de colonización independientes.

También investigamos si existe evidencia en la estructura genética de las poblaciones de las islas que respalde la idea de la colonización por un número pequeño de individuos. Las relaciones filogenéticas recuperaron consistentemente la divergencia entre los linajes del ATM y del continente, con un fuerte apoyo en tres de las cuatro especies. Nuestras estimaciones para el nivel del mar y la línea de costa del oeste de México durante el Pleistoceno mostraron que la distancia entre las islas y el continente era de ∼25 km. Por lo tanto, probamos varios escenarios de colonización de las islas de acuerdo a las relaciones filogenéticas, las redes de haplotipos, las estimaciones del tiempo de divergencia, la demografía histórica y las diferentes fechas de glaciaciones. El escenario más apoyado de colonización del ATM sugiere que fue un solo evento, el cual ocurrió aproximadamente hace 120 mil años cuando surgieron las islas, y que afectó simultáneamente a las cuatro especies de aves paseriformes, lo que concuerda en gran medida con la evidencia geológica.

Resumen en inglés

Studies in evolutionary biology have commonly been focused on insular systems because of their natural geographic isolation and relatively simpler biotas. Using mitochondrial DNA sequences of 4 passerine bird species distributed in the Tres Marías Archipelago (TMA) and the nearby mainland of western Mexico—Cardinalis cardinalis, Turdus rufopalliatus, Vireo hypochryseus, and Icterus pustulatus—we determined interspecific and intraspecific phylogenetic relationships between insular and mainland populations, conducted insular age-based time calibration for the estimation of divergence times, and used Bayesian analyses to examine the colonization history of islands. Specifically, we tested whether the study species from the TMA share the same colonization history since the emergence of the islands ∼120 kya, taking advantage of the reduced isolation due to sea-level fluctuations during the Pleistocene, or whether there were independent colonization events.

We also looked for evidence in the genetic structure of the island populations that would support the idea of colonization by a small number of individuals. Phylogenetic relationships consistently recovered lineage divergence between the TMA and mainland populations, with strong support in 3 of the 4 species. Our estimates for the sea level and coastline of the west coast of Mexico during the Pleistocene showed that the distance between the TMA and the mainland was ∼25 km. We tested several island colonization scenarios according to the phylogenetic relationships, haplotype networks, divergence time estimates, historical demography, and different glaciation dates. The most supported scenario of colonization of the TMA suggests that a single event occurred ∼120 kya when the islands emerged, which is highly concordant with geological evidence, and simultaneously affected the 4 species.


PDF
Resumen en: Español | Inglés |
Resumen en español

La domesticación de plantas y animales permite estudiar diferentes procesos evolutivos, como la selección, adaptación y especiación. En este artículo se describen avances recientes en el estudio de las calabazas, las cuales constituyen el género Cucurbita (Cucurbitaceae) siendo un grupo de plantas herbáceas americanas que incluyen entre 12 y 15 especies. Cucurbita ha tenido seis eventos de domesticación, de los cuales cuatro sucedieron en México. Este es un género relativamente reciente, que surgió en Norte América hace 16 millones de años y sus especies cultivadas mantienen una alta variación genética; Cucurbita pepo es la especie que presenta mayor variación genética,variación asociada a dos domesticaciones independientes, una en el norte de México, y otra en el Sureste de los Estados Unidos. En otra especie, Cucurbita argyrosperma, sus poblaciones de la Península de Yucatán, representan una poza genética diferenciada del resto de la especie. El estudio del genoma de C. argyrosperma y taxa cercanos ha revelado las regiones de su genoma asociadas a la domesticación. Las poblaciones de las especies de este género representan una fuente de importantes recursos genéticos frente al cambio climático y constituyen un buen sistema para el estudio de la domesticación y de diferentes procesos evolutivos.

Resumen en inglés

The domestication of plants and animals allows the study of different evolutionary processes, including selection, adaptation and speciation. Here we describe recent advances in the study of pumpkins and squashes, which constitute the genus Cucurbita (Cucurbitaceae), being a group of herbaceous plants from the Americas that include between 12 and 15 species. Cucurbita has had six domestication events, four of them occurred in Mexico. This is a relatively recent genus that originated in North America 16 million years ago and its cultivated species maintain high levels of genetic variation. Cucurbita pepo is the species with the highest genetic diversity, diversity associated to two independent domestications, one in Northern Mexico and the other in Southern United States. In another species, Cucurbita argyrosperma, the populations from Yucatan Peninsula represents a genetic pool differentiated from the rest of the species. The study of the genome of C. argyrosperma and related taxa has revealed the regions of its genome associated with domestication. The populations of the species of this genus represent a source of important genetic resources in the face of climate change and constitute a good system for the study of domestication and of different evolutionary processes.


PDF PDF
Resumen en: Inglés |
Resumen en inglés

Analyses of genetic variation allow understanding the origin, diversification and genetic resources of cultivated plants. Domesticated taxa and their wild relatives are ideal systems for studying genetic processes of plant domestication and their joint is important to evaluate the distribution of their genetic resources. Such is the case of the domesticated subspecies C. argyrosperma ssp. argyrosperma, known in Mexico as calabaza pipiana, and its wild relative C. argyrosperma ssp. sororia. The main aim of this study was to use molecular data (microsatellites) to assess the levels of genetic variation and genetic differentiation within and among populations of domesticated argyrosperma across its distribution in Mexico in comparison to its wild relative, sororia, and to identify environmental suitability in previously proposed centers of domestication. We analyzed nine unlinked nuclear microsatellite loci to assess levels of diversity and distribution of genetic variation within and among populations in 440 individuals from 19 populations of cultivated landraces of argyrosperma and from six wild populations of sororia, in order to conduct a first systematic analysis of their genetic resources. We also used species distribution models (SDMs) for sororia to identify changes in this wild subspecies’ distribution from the Holocene ( 6,000 years ago) to the present, and to assess the presence of suitable environmental conditions in previously proposed domestication sites. Genetic variation was similar among subspecies (HE = 0.428 in sororia, and HE = 0.410 in argyrosperma). Nine argyrosperma populations showed significant levels of inbreeding. Both subspecies are well differentiated, and genetic differentiation (FST) among populations within each subspecies ranged from 0.152 to 0.652.

Within argyrosperma we found three genetic groups (Northern Mexico, Yucatan Peninsula, including Michoacan and Veracruz, and Pacific coast plus Durango). We detected low levels of gene flow among populations at a regional scale (<0.01), except for the Yucatan Peninsula, and the northern portion of the Pacific Coast. Our analyses suggested that the Isthmus of Tehuantepec is an effective barrier isolating southern populations. Our SDM results indicate that environmental characteristics in the Balsas- Jalisco region, a potential center of domestication, were suitable for the presence of sororia during the Holocene.


8.
- Artículo con arbitraje
Resumen en: Inglés |
Resumen en inglés

Knowledge of the role of geographical and ecological events associated to the divergence process of wild progenitors is important to understand the process of domestication. We analysed the temporal, spatial and ecological patterns of the diversification of Cucurbita, an American genus of worldwide economic importance. We conducted a phylogenetic analysis based on six chloroplast regions (5907 bp) to estimate diversification rates and dates of divergence between taxa. This is the first phylogenetic study to include C. radicans, a wild species that is endemic to the Trans Mexican Volcanic Belt. We performed analysis of ancestral area reconstruction and paleoreconstructions of species distribution models to understand shifts in wild species ranges. We used principal component analysis (PCA) and multivariate analysis of variance (MANOVA) to evaluate the environmental differentiation among taxa within each clade. The phylogenetic analyses showed good support for at least six independent domestication events in Cucurbita. The genus Cucurbita showed a time of divergence of 11.24 Ma (6.88–17 Ma 95% HDP), and the dates of divergence between taxa within each group ranged from 0.35 to 6.58 Ma, being the divergence between C. lundelliana and C. okeechobeensis subsp. martinezii the most recent. The diversification rate of the genus was constant through time.

The diversification of most wild taxa occurred during the Pleistocene, and its date of divergence is concordant with the dates of divergence reported for specialized bees of the genera Xenoglossa and Peponapis, suggesting a process of coevolution between Cucurbita and their main pollinators that should be further investigated. Tests of environmental differentiation together with ancestral area reconstruction and species distribution models past projections suggest that divergence was promoted by the onset of geographic barriers and secondary range contraction and by expansion related to glacial-interglacial cycles.