Ausencia de la delección de 9 bp COII/tRNA lys en aborígenes de Fuego- Patagonia mediante análisis de DNA antiguo
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1993
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Se ha estudiado la delección de 9 bp COII/tRNA lys de la región V del DNA mitocondrial de 30 muestras antiguas de aborígenes de la región magallánica (kawéskar, yamana, selknam y aónikenk) por medio de la técnica de la PCR (Reacción en Cadena de la Polimerasa). Los restos analizados son mayoritariamente dientes, con una antigüedad que abarca del siglo XIX hasta hace unos 4000 años en el caso de Cueva Lago Sofía. Se han obtenido amplificaciones positivas en 24 casos, que muestran la ausencia de la delección de 9 bp en los cuatro grupos estudiados. La delección es de origen asiático y ha sido detectada en diversos grupos de aborígenes americanos, en frecuencias que van del 0% al 71%. Su ausencia en los fueguinos podría indicar que el grupo migratorio correspondiente a los paleoindios no la poseía y que migraciones posteriores la habrían introducido en América. Una hipótesis alternativa es que la delección estuviera presente originariamente y se hubiera perdido por efecto de la deriva genética a lo largo de la colonización de Sudamérica. Debe tenerse en cuenta que se trata de un marcador genético sencillo y, por lo tanto, de valor limitado en la interpretación filogenética. Hay actualmente en estudio otros marcadores mitoconcriales que ayudarán a clarificar la posición de estas interesantes poblaciones en el contexto genético evolutivo de los primeros pobladores americanos.
We have studied the 9 bp COII/tRNA lys mt-DNA Region V deletion in a sample of 30 ancient samples of aborigines from the Magellan region (kawéskar, yamana, selknam, and aónikenk) by PCR (Polymerase Chain Reaction). The remains analyzed mainly consist of teeth dating from 4,000 BP (Cueva Lago Sofía) till the XIXth Century. We have obtained positive amplifications in 24 of the samples, belonging to the four analyzed groups, which do not show the 9 bp deletion. The 9 bp genetic marker has an asiatic origin and has been detected in several amerindian groups, with varying frequencies ranging from 0% to 71%. Its absence in the Fueguian groups suggests that the paleoindian migration might have lacked it; later migratory movements might have introduced it in the American continent. An alternative hypothesis might be the deletion would have been present in the first settlers, and it would have been lost, along the colonization of South America, by genetic drift. It must be taken into account that the 9 bp deletion is a simple genetic marker and, thus, it has a limited value for making a filogenetic interpretation. Presently we are analyzing other mitochondrial DNA markers that might help to clarify the genetic affinities of the first settlers in Fuego-Patagonia from an evolutionary perspective.
We have studied the 9 bp COII/tRNA lys mt-DNA Region V deletion in a sample of 30 ancient samples of aborigines from the Magellan region (kawéskar, yamana, selknam, and aónikenk) by PCR (Polymerase Chain Reaction). The remains analyzed mainly consist of teeth dating from 4,000 BP (Cueva Lago Sofía) till the XIXth Century. We have obtained positive amplifications in 24 of the samples, belonging to the four analyzed groups, which do not show the 9 bp deletion. The 9 bp genetic marker has an asiatic origin and has been detected in several amerindian groups, with varying frequencies ranging from 0% to 71%. Its absence in the Fueguian groups suggests that the paleoindian migration might have lacked it; later migratory movements might have introduced it in the American continent. An alternative hypothesis might be the deletion would have been present in the first settlers, and it would have been lost, along the colonization of South America, by genetic drift. It must be taken into account that the 9 bp deletion is a simple genetic marker and, thus, it has a limited value for making a filogenetic interpretation. Presently we are analyzing other mitochondrial DNA markers that might help to clarify the genetic affinities of the first settlers in Fuego-Patagonia from an evolutionary perspective.
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Estudios genéticos, DNA fueguino
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Anales del Instituto de la Patagonia, Vol. 22, pp. 181-191, 1993-94.