Jane Peterson

Marker papers and data citation.

1. Melamed, P., Chong, K.L. & Johansen, M.V. Nat. Genet. 36, 786–787 (2004). 2. de Boer, J.G., Yazawa, R., Davidson, W.S. & Koop, B.F. BMC Genomics 8, 422 (2007). 3. Matveev, V., Nishihara, H. & Okada, N. Mol. Biol. Evol. 24, 1656–1666 (2007). 4. Matveev, V. & Okada, N. Gene 434, 16–28 (2009). 5. Sorek, R. & Safer, H.M. Nucleic Acids Res. 31, 1067– 1074 (2003). our experimental results, our in silico analysis and the literature concerning schistosome and salmon behavior and ecology (Supplementary Note and Supplementary Table 2) do not support the view that gene transfer occurred from salmonids to schistosomes or between their ancestors. The sample history of the expressed sequence tag library ‘Adult SjC 7/94’ is well documented in the ‘note’ section of GenBank accession number BU712912. The authors of the database entry mention that 2–3% of the clones contain inserts with homology to salmon DNA. Their phrasing suggests that they considered only the remaining sequences to come from S. japonicum. Salmon sperm DNA has traditionally been used as a carrier material in many laboratories. Cross-species and vector contamination would not be surprising and are found in many databases5. We hope the present work stimulates re-examination of evolutionary theories concerning Schistosomatidae and Salmonidae based on the initial—and we BU711870.1 spanning the primer binding sites with the sequence of the PCR product showed 47.6% sequence identity (using the Needle algorithm, http://www.ebi.ac.uk/ Tools/emboss/align/). Comparison with the genomic sequence of S. mansoni identified the PCR product as part of a unique sequence on scaffold 000213 (positions 409,215–409,650, 99% identity). For the Hpa primer pairs1, the PCR product had a size of 175 bp instead of the predicted size of 159 bp, and alignment with AY834401.1 showed only 45% similarity. A BLAST search returned a unique 100% match on the S. mansoni genomic scaffold 000001 (positions 1,882,577–1,882,721). The predicted size for the Igf primer pair is 266 bp, whereas the observed size was 1,041 bp, and the similarity to AY834397.1 was very low (18.7% similarity). Primer sequences are given in Supplementary Table 1. In short, we did not observe PCR amplification with the previously used primers of the putative salmonid-like repeat sequences in S. mansoni or S. japonicum. Taken together,

Close Linkage of Transferred Galactokinase and Thymidine Kinase Genes in a Transformant after DNA-Mediated Gene Transfer

There are many similarities and some differences between DNA- and chromosome-mediated gene transfer. The cellular uptake of both DNA1 and metaphase chromosomes2 involves phagocytosis and there is a requirement for co-precipitation of the donor DNA3 or chromosomes4 with calcium phosphate to achieve optimal frequencies of gene transfer. In either method, transformants usually initially exhibit an unstable phenotype, and stabilization ultimately occurs through covalent integration of the donor DNA with recipient chromosomal DNA at multiple non-homologous sites. The optimal frequency for gene transfer is dependent upon many factors but a higher frequency of transfer has been reported for chromosome-than DNA-mediated gene transfer under similar conditions.5