Fig. (2d) PCA plots based on DGGE profiles of 16S rRNA gene PCR-derived amplicons of BAL samples collected from six weeks old C57Bl/6 mice. The mice are both male and female offspring from C57Bl/6 dams exposed i.n. to either PBS or CNT particles. The colors represent red: CNT-male, pink CNT-female and dark blue PBS-male and light- blue PBS –female (n=20). DGGE: denaturing gradient gel electrophoresis after DGGE-PCR: polymerase chain reaction.