“…Double-stranded cDNAs were synthesized by the method of Land et al,25) which should allow the cloning of the complete cDNA including the 5' region of the mRNA. Transformants were screened by hybridization with a 32P-Iabeled HaeIII-EcoRI fragment of CX s1 -casein cDNA from clone 1 19 ) (see MATERIALS AND METHODS and also Fig. 1).…”