Disease-associated XMRV sequences are consistent with laboratory contamination

Retrovirology

Table 1 Screening of genomic DNA from 9 inbred and 3 wild-derived inbred mice using Taqman PCR

Mice names and Jackson lab identification numbers (ID) are shown as are the proportion of positive 454-sequencing reads that contain the XMRV 24 nt deletion signature sequence compared to the total number of reads obtained from each amplification reaction. Cycle threshold (Ct) values for Taqman PCR performed with primer sets targeting XMRV gag-leader, integrase and MLV-X-gag are also shown. Template amounts were 1 ng, 200 ng and 2 ng respectively. Lower amounts of genomic DNA were used in gag and gag-leader PCRs due to the high number of amplicons detected. We define positive PCR as those with a Ct of less than 41. This cut off was chosen on the basis that PCR quantitation of plasmid concentrations of 5 molecules per PCR give Ct values of 40. PCR detection of concentrations below 5 molecules became stochastic and are thus below the limit of reliable detection (data not shown). Primers are shown in Table S1.

ISSN: 1742-4690