DNA extraction from soils: Old bias for new microbial diversity analysis methods

The impact of three different soil DNA extraction methods on bacterial dive rsity was evaluated using PCR-based 16S ribosomal DNA analysis, DNA extract ed directly from three soils showing contrasting physicochemical properties was subjected to amplified ribosomal DNA restriction analysis and ribosoma l intergenic spacer analysis (RISA). The obtained RISA patterns revealed cl early that both the phylotype abundance and the composition of the indigeno us bacterial community are dependent on the DNA recovery method used. In ad dition, this effect was also shown in the context of an experimental study aiming to estimate the impact on soil biodiversity of the application of fa rmyard manure or sewage sludge onto a monoculture of maize for 15 years.