an outbreak of equine leukoencephalomalacia at oaxaca, mexico, associated with fumonisin b1.equine leukoencephalomalacia (elem), swine pulmonary oedema and human oesophageal cancer have been associated with fumonisine b1 (fb1) ingestion. for the first time in this study it is reported that fb1 was identified as being associated with an outbreak of elem at oaxaca, mexico. symptoms of elem and equine venezuelan encephalitis (eve) are similar and a different diagnosis is obligatory. in the geographical area (oaxaca, mexico) where donkeys died showing a neurological syndrome, 14 corn sampl ...19989719762
nutrient intake and growth of preschool children from different socioeconomic regions in the city of oaxaca, méxico.dietary intake and anthropometric measurements were determined in 124 preschool children, aged 4-6 years, living in the city of oaxaca, méxico. the children were classified by socioeconomic status, depending upon their living conditions and family income. a composite diet representing the typical diet according to socioeconomic group was formulated and chemically evaluated. corn tortillas and beans were the primary protein and energy sources for the children of this study. the inclusion of dairy ...200010838462
the earliest archaeological maize (zea mays l.) from highland mexico: new accelerator mass spectrometry dates and their implications.accelerator mass spectrometry age determinations of maize cobs (zea mays l.) from guilá naquitz cave in oaxaca, mexico, produced dates of 5,400 carbon-14 years before the present (about 6,250 calendar years ago), making those cobs the oldest in the americas. macrofossils and phytoliths characteristic of wild and domesticated zea fruits are absent from older strata from the site, although zea pollen has previously been identified from those levels. these results, together with the modern geograph ...200111172082
archaeological evidence of teosinte domestication from guilá naquitz, oaxaca.analysis of the three most ancient zea mays inflorescence fragments from guilá naquitz, oaxaca, mexico shows they did not disarticulate naturally, indicating that agricultural selection of domesticated teosinte was underway by 5,400 (14)c years before the present (about 4,200 dendrocalibrated years b.c.). the cooccurrence of two-ranked specimens with two rows and four rows of grain and numerous additional morphological characteristics of these specimens support hypotheses based on molecular and ...200111172083
transgenic dna introgressed into traditional maize landraces in oaxaca, mexico.concerns have been raised about the potential effects of transgenic introductions on the genetic diversity of crop landraces and wild relatives in areas of crop origin and diversification, as this diversity is considered essential for global food security. direct effects on non-target species, and the possibility of unintentionally transferring traits of ecological relevance onto landraces and wild relatives have also been sources of concern. the degree of genetic connectivity between industrial ...200111734853
no credible scientific evidence is presented to support claims that transgenic dna was introgressed into traditional maize landraces in oaxaca, mexico. 200211874106
biodiversity (communications arising): maize transgene results in mexico are artefacts.quist and chapela's conclusion that the transgenes they claim to have detected in native maize in oaxaca, mexico, are predominantly reassorted and inserted into a "diversity of genomic contexts" seems to be based on an artefact arising from the inverse polymerase chain reaction (i-pcr) they used to amplify sequences flanking 35s transgenes from cauliflower mosaic virus (camv).200211935145
a n2-fixing endophytic burkholderia sp. associated with maize plants cultivated in the frame of a survey of potentially endophytic n2-fixing burkholderia associated with maize in mexico, its country of origin, the soil of an indigenous maize field near oaxaca was studied. under laboratory conditions, plant seedlings of two ancient maize varieties were used as a trap to select endophyte candidates from the soil sample. among the n2 fixers isolated from inside plant tissues and able to grow on pcat medium, the most abundant isolates belonged to genus burkholderia (api 20ne, r ...200212030700
patterns of population structure in maize landraces from the central valleys of oaxaca in mexico.assessing the impact of farmer management of maize landraces in the central valleys of oaxaca, mexico is crucial to an understanding of maize evolution, as it was first domesticated there. in this paper, we report on the impact of traditional farmer management of maize populations in this region in structuring molecular diversity and on the population dynamics of maize landraces. these populations, from a sample of local landraces cultivated by farmers in six villages, show little among-populati ...200414666127
population structure and strong divergent selection shape phenotypic diversification in maize conserve the long-term selection potential of maize, it is necessary to investigate past and present evolutionary processes that have shaped quantitative trait variation. understanding the dynamics of quantitative trait evolution is crucial to future crop breeding. we characterized population differentiation of maize landraces from the state of oaxaca, mexico for quantitative traits and molecular markers. qst values were much higher than fst values obtained for molecular markers. while low va ...200414666128
absence of detectable transgenes in local landraces of maize in oaxaca, mexico (2003-2004).in 2000, transgenes were detected in local maize varieties (landraces) in the mountains of oaxaca, mexico [quist, d. & chapela, i. h. (2001) nature 414, 541-543]. this region is part of the mesoamerican center of origin for maize (zea mays l.), and the genetic diversity that is maintained in open-pollinated landraces is recognized as an important genetic resource of great cultural value. the presence of transgenes in landraces was significant because transgenic maize has never been approved for ...200516093316
early maize (zea mays l.) cultivation in mexico: dating sedimentary pollen records and its implications.a sedimentary pollen sequence from the coastal plain of veracruz, mexico, demonstrates maize cultivation by 5,000 years ago, refining understanding of the geography of early maize cultivation. methodological issues related to bioturbation involved in dating that record combine with its similarity to a pollen sequence from the coastal plain of tabasco, mexico, to suggest that the inception of maize cultivation in that record occurred as much as 1,000-2,000 years more recently than the previously ...200616418287
detecting (trans)gene flow to landraces in centers of crop origin: lessons from the case of maize in mexico.there is much discussion of the probability of transgene flow from transgenic crop varieties to landraces and wild relatives in centers of origin or diversity, and its genetic, ecological, and social consequences. without costly research on the variables determining gene flow, research on transgene frequencies in landrace (or wild relative) populations can be valuable for understanding transgene flow and its effects. minimal research requirements include (1) understanding how farmer practices an ...200616827547
transgenes in mexican maize: molecular evidence and methodological considerations for gmo detection in landrace populations.a possible consequence of planting genetically modified organisms (gmos) in centres of crop origin is unintended gene flow into traditional landraces. in 2001, a study reported the presence of the transgenic 35s promoter in maize landraces sampled in 2000 from the sierra juarez of oaxaca, mexico. analysis of a large sample taken from the same region in 2003 and 2004 could not confirm the existence of transgenes, thereby casting doubt on the earlier results. these two studies were based on differ ...200919143938
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