Rymarquis, L.A., Handley, J.M., Thomas, M. and Stern, D.B.
Notes: These authors describe map-based cloning tools for Chlamydomonas reinhardtii, (green yeast). In this case-based study of existing and projected resources for C. reinhardtii mapping, mcd4 and mcd5 mutants were mapped by crossing to the infertile strain known as Chlamydomonas grossii, S1-D2, with several known marker sites. To reduce the time and expense of mapping, bulked segregant analysis (BSA) and marker duplexing were evaluated. In BSA, DNAs from multiple segregating progeny (up to six in this study) are combined, and results from PCR-based markers are examined for significant bias from a roughly equal contribution from each parent. This case study used 57–72 markers to span the 1,107-cM genome using approximately 3,350 PCR amplifications. The researchers picked single colonies from a plate and placed each colony in a hypotonic EDTA solution. After boiling for 5 minutes, the supernatant was collected by centrifugation and the DNA quantitated. Twenty nanograms of DNA thus isolated was used as the template for PCR. The reaction included GoTaq® DNA polymerase with the enhancers 8.5%glycerol and 0.83% formamide in a 30µl reaction. Forty cycles of amplification were performed and the results were analyzed by agarose gel electrophoresis. The various amplification reactions included the use of BSA and both monoplex and duplex reactions with amplicons of 90bp–625bp. (3279)