Unstable Linkage Between Genetic Markers in Transformation

Abstract
A new type of association of genetic markers in a transformation system has been discovered. Linkage between certain markers is detectable only under particular conditions of deoxyribonucleic acid (DNA) extraction and is sensitive to dilution of the DNA. The data suggest that this unstable association occurs between markers which are on the same molecule but separated by a molecular distance sufficiently great for linkage to be preserved only by mild DNA extraction procedures and at high concentrations of DNA. Linkage can be stabilized by dilution in the presence of a carrier DNA. By use of these unstable linkages, the genetic map of Bacillus subtilis has been extended in both directions from the aromatic gene cluster.