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Los genes microbianos en el genoma humano: ¿transferencia lateral o pérdida de genes?
S L Salzberg1, O White, J Peterson
1The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA. salzberg@tigr.org
Science (New York, N.Y.)
|May 19, 2001
Resumen
Este estudio investigó la transferencia de genes entre humanos y bacterias. Si bien algunos genes parecían compartidos, la pérdida de genes y los factores evolutivos ofrecen una explicación más probable que la transferencia horizontal de genes.
Área de la Ciencia:
- La genómica es la genómica.
- Biología evolutiva Biología evolutiva.
- La genómica comparada es una genómica comparada.
Sus antecedentes:
- Los orígenes del genoma humano se debaten, con la transferencia horizontal de genes (HGT) de los procariotas propuestos.
- Investigar el intercambio de genes entre especies puede revelar relaciones y mecanismos evolutivos.
Objetivo del estudio:
- Para analizar el genoma humano en busca de evidencia de HGT de organismos procariotas.
- Identificar genes exclusivamente compartidos entre humanos y bacterias como potenciales candidatos a la HGT.
Principales métodos:
- Realizó comparaciones de secuencias de proteínas en diversos organismos: humano, mosca de la fruta, gusano nematodo, levadura, hierba mostaza, parásitos eucariotas y procariotas.
- Recogió todos los genes compartidos entre el genoma humano y cada grupo de comparación.
- Centrado en genes exclusivamente compartidos entre humanos y bacterias.
Principales resultados:
- Se descubrió que aproximadamente 40 genes se comparten exclusivamente entre humanos y bacterias.
- Estos 40 genes fueron inicialmente considerados ejemplos candidatos de HGT de bacterias a vertebrados.
- También se consideraron explicaciones alternativas, incluida la pérdida de genes y la variación de la tasa evolutiva.
Conclusiones:
- Si bien se identificaron genes candidatos para la transferencia horizontal de genes de las bacterias a los humanos, las explicaciones alternativas son más plausibles.
- La pérdida de genes, los efectos del tamaño de la muestra y la variación de la tasa evolutiva proporcionan una interpretación más biológicamente sólida para el intercambio de genes observado.
- El estudio sugiere precaución al atribuir todos los genes compartidos a la transferencia horizontal directa de genes sin considerar otras fuerzas evolutivas.
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