Degrees of lineage-specific transcription in MULE superfamily (excluding the TRAP-like class). The phylogenetic tree was generated from a multiple alignment of conceptually translated sequences by using neighbor-joining methods and rooted with soybean Soymar1. Bootstrap values were calculated from 1,000 replicates. Sample numbers are identical to those in Table 2. Shades of gray indicate the magnitude of transcription signals, which are based on microarray hybridization signals without units. Names of previously reported members are shown. Names in parenthesis indicate members not covered by microarray. Transcriptional active clades are highlighted by bars. *Previously reported members with transcription or transposition.