Publicaciones

@article{Figueredo2015,

title = {Genetic structure of coexisting wild and managed agave populations: implications for the evolution of plants under domestication},

author = {Carmen Julia Figueredo and Alejandro Casas and Antonio González-Rodríguez and Jafet M. Nassar and Patricia Colunga-GarcíaMarín and Víctor Rocha-Ramírez},

doi = {10.1093/aobpla/plv114},

issn = {2041-2851},

year  = {2015},

date = {2015-01-01},

journal = {AoB Plants},

pages = {plv114},

abstract = {Domestication is a continuous evolutionary process guided by humans. This process leads to divergence in characteristics such as behavior, morphology, or genetics, between wild and managed populations. Agaves have been important resources for Mesoamerican peoples since prehistory. Some species are domesticated and others vary in degree of domestication. Agave inaequidens is used in central Mexico to produce mescal, and a management gradient from gathered wild and silvicultural populations, as well as cultivated plantations, has been documented. Significant morphological differences were reported among wild and managed populations, and a high phenotypic variation in cultivated populations composed by plants from different populations. We evaluated levels of genetic diversity and structure associated with management, hypothesizing that high morphological variation would be accompanied by high genetic diversity in populations with high gene flow and low genetic structure among managed and unmanaged populations. Wild, silvicultural, and cultivated populations were studied, collecting tissue of 19 to 30 plants per population. Through 10 nuclear microsatellite loci we compared population genetics parameters. We analysed partition of variation associated with management categories to estimate gene flow among populations. A. inaequidens exhibits high levels of genetic diversity (He=0.707) and moderate genetic structure (FST=0.112). No differences were found in levels of genetic diversity among wild (He=0.704), silviculturally managed (He=0.733), and cultivated (He=0.698) populations. Bayesian analysis indicated that five genetic clusters best fit the data, with genetic groups corresponding to habitats where populations grow rather than to management. Migration rates ranged from zero between two populations to markedly high among others (M=0.73-35.25). Natural mechanisms of gene flow and the dynamic management of agave propagules among populations favor gene flow and the maintenance of high levels of variation within all populations. The slight differentiation associated with management indicates that domestication is in an incipient stage.},

keywords = {agave inaequidens, agaves, conservation genetics, domestication, genetic structure, genetic variation},

pubstate = {published},

tppubtype = {article}

}

@article{Parra2015,

title = {Spatial distribution of genetic variation of Stenocereus pruinosus (Otto) Buxb. in Mexico: analysing evidence on the origins of its domestication},

author = {Fabiola Parra and Alejandro Casas and Víctor Rocha and Antonio Gonzàlez-Rodríguez and Salvador Arias-Montes and Hernando Rodríguez-Correa and Janet Tovar},

doi = {10.1007/s10722-014-0199-x},

issn = {15735109},

year  = {2015},

date = {2015-01-01},

journal = {Genetic Resources and Crop Evolution},

volume = {62},

issue = {6},

pages = {893-912},

abstract = {We studied populations of Stenocereus pruinosus throughout Mexico, a species important for its edible fruit. The Tehuacán Valley is setting of ancient and the currently most active management of S. pruinosus; we hypothesized Tehuacán as the original area of domestication of S. pruinosus and expected to find there its highest genetic variation and original source of genes of cultivated plants. Through nuclear microsatellite loci we studied spatial distribution of genetic variation and population differentiation. We sampled wild and managed populations of the Central-western (Tehuacán, Central Valleys and Tehuantepec, Oaxaca), north-eastern (Huasteca) and south-eastern (Chiapas) regions. Differences among regions and populations were compared through homogeneity and exact test for FIS , AMOVA, Bayesian analysis, and genetic barriers. A niche analysis allowed corroborating taxonomic identity of populations. The highest genetic diversity was in Tehuantepec (HE = 0.841), decreasing towards the extremes of distribution (HE = 0.242 in Huasteca},

keywords = {Centre of origin, Columnar cacti, domestication, Genetic resources conservation, Mesoamerica, Stenocereus pruinosus},

pubstate = {published},

tppubtype = {article}

}

@article{Figueredo2014,

title = {Morphological variation, management and domestication of 'maguey alto' (Agave inaequidens) and 'maguey manso' (A. hookeri) in Michoacán, México},

author = {Carmen J. Figueredo and Alejandro Casas and Patricia Colunga-GarcíaMarín and Jafet M. Nassar and Antonio González-Rodríguez},

doi = {10.1186/1746-4269-10-66},

issn = {17464269},

year  = {2014},

date = {2014-01-01},

journal = {Journal of Ethnobiology and Ethnomedicine},

volume = {10},

issue = {1},

pages = {1-12},

abstract = {Background: Agave inaequidens and A. hookeri are anciently used species for producing the fermented beverage 'pulque', food and fiber in central Mexico. A. inaequidens is wild and cultivated and A. hookeri only cultivated, A. inaequidens being its putative wild relative. We analysed purposes and mechanisms of artificial selection and phenotypic divergences between wild and managed populations of A. inaequidens and between them and A. hookeri, hypothesizing phenotypic divergence between wild and domesticated populations of A. inaequidens in characters associated to domestication, and that A. hookeri would be phenotypically similar to cultivated A. inaequidens. Methods: We studied five wild and five cultivated populations of A. inaequidens, and three cultivated populations of A. hookeri. We interviewed agave managers documenting mechanisms of artificial selection, and measured 25 morphological characters. Morphological similarity and differentiation among plants and populations were analysed through multivariate methods and ANOVAs. Results: People recognized 2-8 variants of A. inaequidens; for cultivation they select young plants collected in wild areas recognized as producing the best quality mescal agaves. Also, they collect seeds of the largest and most vigorous plants, sowing seeds in plant beds and then transplanting the most vigorous plantlets into plantations. Multivariate methods classified separately the wild and cultivated populations of A. inaequidens and these from A. hookeri, mainly because of characters related with plant and teeth size. The cultivated plants of A. inaequidens are significantly bigger with larger teeth than wild plants. A. hookeri are also significatly bigger plants with larger leaves but lower teeth density and size than A. inaequidens. Some cultivated plants of A. inaequidens were classified as A. hookeri, and nearly 10% of A. hookeri as cultivated A. inaequidens. Wild and cultivated populations of A. inaequidens differed in 13 characters, whereas A. hookeri differed in 23 characters with wild populations and only in 6 characters with cultivated populations of A. inaequidens. Conclusions: Divergence between wild and cultivated populations of A. inaequidens reflect artificial selection. A. hookeri is similar to the cultivated A. inaequidens, which supports the hypothesis that A. hookeri could be the extreme of a domestication gradient of a species complex.},

keywords = {domestication, Mescal agave, Phenotypic variation, Plant management, Pulque},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Round and large: Morphological and genetic consequences of artificial selection on the gourd tree Crescentia cujete by the Maya of the Yucatan Peninsula, Mexico},

author = {Xitlali Aguirre-Dugua and Luis E. Eguiarte and Antonio González-Rodrgíuez and Alejandro Casas},

doi = {10.1093/aob/mcs068},

issn = {03057364},

year  = {2012},

date = {2012-01-01},

journal = {Annals of Botany},

volume = {109},

issue = {7},

pages = {1297-1306},

abstract = {Background and AimsArtificial selection, the main driving force of domestication, depends on human perception of intraspecific variation and operates through management practices that drive morphological and genetic divergences with respect to wild populations. This study analysed the recognition of varieties of Crescentia cujete by Maya people in relation to preferred plant characters and documents ongoing processes of artificial selection influencing differential chloroplast DNA haplotype distribution in sympatric wild and home-garden populations. MethodsFifty-three home gardens in seven villages (93 trees) and two putative wild populations (43 trees) were sampled. Through semi-structured interviews we documented the nomenclature of varieties, their distinctive characters, provenance, frequency and management. Phenotypic divergence of fruits was assessed with morphometric analyses. Genetic analyses were performed through five cpDNA microsatellites. Key ResultsThe Maya recognize two generic (wild/domesticated) and two specific domesticated (white/green) varieties of Crescentia cujete. In home gardens, most trees (68%) were from domesticated varieties while some wild individuals (32%) were tolerated. Cultivation involves mainly vegetative propagation (76%). Domesticated fruits were significantly rounder, larger and with thicker pericarp than wild fruits. Haplotype A was dominant in home gardens (76%) but absent in wild populations. Haplotypes B-F were found common in the wild but at low frequency (24%) in home gardens. ConclusionsThe gourd tree is managed through clonal and sexual propagules, fruit form and size being the main targets of artificial selection. Domesticated varieties belong to a lineage preserved by vegetative propagation but propagation by seeds and tolerance of spontaneous trees favour gene flow from wild populations. Five mutational steps between haplotypes A and D suggest that domesticated germplasm has been introduced to the region. The close relationship between Maya nomenclature and artificial selection has maintained the morphological and haplotypic identity (probably for centuries) of domesticated Crescentia despite gene flow from wild populations. © The Author 2012. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.},

keywords = {Artificial selection, Bignoniaceae, Crescentia cujete, domestication, Maya, Mesoamerica, Microsatellites, traditional plant management},

pubstate = {published},

tppubtype = {article}

}

@article{Parra2010,

title = {Evolution under domestication: Ongoing artificial selection and divergence of wild and managed Stenocereus pruinosus (Cactaceae) populations in the Tehuacán Valley, Mexico},

author = {Fabiola Parra and Alejandro Casas and Juan Manuel Peñaloza-Ramírez and Aurea C. Cortés-Palomec and Víctor Rocha-Ramírez and Antonio González-Rodríguez},

doi = {10.1093/aob/mcq143},

issn = {10958290},

year  = {2010},

date = {2010-01-01},

journal = {Annals of Botany},

volume = {106},

issue = {3},

pages = {483-496},

abstract = {Background and AimsThe Tehuacán Valley in Mexico is a principal area of plant domestication in Mesoamerica. There, artificial selection is currently practised on nearly 120 native plant species with coexisting wild, silvicultural and cultivated populations, providing an excellent setting for studying ongoing mechanisms of evolution under domestication. One of these species is the columnar cactus Stenocereus pruinosus, in which we studied how artificial selection is operating through traditional management and whether it has determined morphological and genetic divergence between wild and managed populations.MethodsSemi-structured interviews were conducted with 83 households of three villages to investigate motives and mechanisms of artificial selection. Management effects were studied by comparing variation patterns of 14 morphological characters and population genetics (four microsatellite loci) of 264 plants from nine wild, silvicultural and cultivated populations.Key ResultsVariation in fruit characters was recognized by most people, and was the principal target of artificial selection directed to favour larger and sweeter fruits with thinner or thicker peel, fewer spines and pulp colours others than red. Artificial selection operates in agroforestry systems favouring abundance (through not felling plants and planting branches) of the preferred phenotypes, and acts more intensely in household gardens. Significant morphological divergence between wild and managed populations was observed in fruit characters and plant vigour. On average, genetic diversity in silvicultural populations (HE = 0·743) was higher than in wild (HE = 0·726) and cultivated (HE = 0·700) populations. Most of the genetic variation (90·58 ) occurred within populations. High gene flow (NmFST > 2) was identified among almost all populations studied, but was slightly limited by mountains among wild populations, and by artificial selection among wild and managed populations.ConclusionsTraditional management of S. pruinosus involves artificial selection, which, despite the high levels of gene flow, has promoted morphological divergence and moderate genetic structure between wild and managed populations, while conserving genetic diversity. © The Author 2010.},

keywords = {Cactaceae, Columnar cacti, crop evolution, domestication, Mesoamerica, Stenocereus pruinosus, traditional plant management},

pubstate = {published},

tppubtype = {article}

}

@article{Oyama2006,

title = {Genetic structure of wild and domesticated populations of Capsicum annuum (Solanaceae) from northwestern Mexico analyzed by RAPDs},

author = {Ken Oyama and Sergio Hernández-Verdugo and Carla Sánchez and Antonio González-Rodríguez and Pedro Sánchez-Peña and José Antonio Garzón-Tiznado and Alejandro Casas},

doi = {10.1007/s10722-004-2363-1},

issn = {09259864},

year  = {2006},

date = {2006-01-01},

journal = {Genetic Resources and Crop Evolution},

volume = {53},

issue = {3},

pages = {553-562},

abstract = {Levels of genetic variation and genetic structure of 15 wild populations and three domesticated populations of Capsicum annuum were studied by RAPD markers. A total of 166 bands (all of them polymorphic) and 126 bands (125 of them polymorphic) were amplified in wild and domesticated populations, respectively. Mean percentage of polymorphism was 34.2% in wild populations and 34.7% in domesticated populations. Mean and total genetic diversity were 0.069 and 0.165 for wild populations and 0.081 and 0.131 for domesticated populations. Parameters of genetic diversity estimated from 54 bands with frequencies ≥1 - (3/n) (n = sample size) showed that 56.7% of the total variation was within and 43.3% among wild populations, whereas 67.8% of the variation was within and 32.2% among domesticated populations. AMOVA indicated that total genetic diversity was equally distributed within (48.9 and 50.0%) and among (50.0 and 51.1%) populations in both wild and domesticated samples. Wild and domesticated populations were clearly resolved in a UPGMA dendrogram constructed from Jaccard's distances (average GD = 0.197), as well as by AMOVA (17.2% of variance among populations types},

keywords = {capsicum annuum, crop evolution, domestication, Genetic resources conservation, RAPDs, Solanaceae},

pubstate = {published},

tppubtype = {article}

}