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Los análisis filogenéticos no apoyan las transferencias horizontales de genes de las bacterias a los vertebrados
M J Stanhope1, A Lupas, M J Italia
1Bioinformatics, GlaxoSmithKline, Collegeville, PA 19426, USA. Michael_J_Stanhope@sbphrd.com
Nature
|June 22, 2001
Resumen
La transferencia horizontal de genes (HGT) es clave para la evolución del genoma. Un estudio encontró que la mayoría de los genes HGT propuestos en humanos en realidad son heredados de antepasados comunes, no de transferencia bacteriana directa.
Área de la Ciencia:
- La genómica es la genómica.
- Biología evolutiva Biología evolutiva.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La transferencia horizontal de genes (HGT) es un motor significativo de la evolución del genoma en los procariotas.
- Un reciente análisis del genoma humano sugirió numerosos eventos directos de HGT entre bacterias y vertebrados.
- Se espera que tales eventos en organismos multicelulares ocurran solo en la línea germinal.
Objetivo del estudio:
- Investigar la validez de los eventos directos de HGT propuestos entre bacterias y vertebrados en el genoma humano.
- Para determinar el origen evolutivo de los genes sospechosos de haber sufrido HGT.
Principales métodos:
- Análisis filogenético de 28 genes confirmados en el genoma humano a través de la reacción en cadena de la polimerasa (PCR).
- Comparación de secuencias de genes con bases de datos que incluyen etiquetas de secuencias expresadas de no vertebrados (EST).
Principales resultados:
- El análisis filogenético indicó que la mayoría de los genes HGT putativos están presentes en eucariotas derivados de forma más antigua.
- La presencia de genes se explica mejor por la ascendencia común en lugar de HGT directa de las bacterias a los vertebrados.
- No se respaldó la evidencia de HGT bacteriana directa a los vertebrados sin eucariotas intermedios.
Conclusiones:
- La mayoría de los eventos bacterianos HGT propuestos en el genoma humano son probablemente artefactos de ascendencia compartida.
- El análisis filogenético es crucial para identificar con precisión los eventos de HGT.
- La HGT directa de las bacterias a los vertebrados es menos común de lo que se sugería anteriormente.
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