Target preparation strategies can also affect these parameters. Amplification of community DNA can increase sensitivity. WCGA was able to representatively amplify 1-250 ng of community DNA (Wu et al., 2006a) , increasing the detection limit from 25 ng to 10 pg (2 bacterial cells); however, using such small quantities of starting material greatly increases the amplification bias compared to the bias observed with 1 ng of DNA. Labeling methods can also affect sensitivity. For example, cyanine dye-doped nanoparticles or tyramide signal amplification labeling are able to increase sensitivity 10-fold (Denef et al., 2003; Zhou and Zhou, 2004) .