Figure 1

Generation of stable H. volcanii × H. mediterranei hybrids. (A) The genomic organization of the selectable markers involved in the study. (B) Generation of a stable hybrid. H133 was transformed with pTA160 trpA, and upon selection on media lacking thymidine the trpA marker was integrated in the hdrB locus, generating UG241. UG241 was mated with WR646, which are autotrophs for thymidine and tryptophan, respectively. The mated colonies were selected on a media lacking thymidine and tryptophan. Small circles indicate the plasmids and the rectangle represents the chromosome.