Nucleotide substitution: A?G. Two RFLP alterations: The EcoRI-EcoRV fragment between -383 and -211 shows a 12bp duplication at -285, of sequences located between -255 and -244, a 1bp insertion at -243 and a single base deletion at -359. There are also 5 single base substitutions. In the EcoRV-EcoRI fragment between -211 and +371, a single base insertion (+15), a single base deletion (+359) and five substitutions have occurred. In addition there is a notable A to G transition at position -226 in the S sequence motif.

Regulatory variant.

Ddc⁺⁴ DNA was cloned and examined by acrylamide gel electrophoresis of restriction fragments. Six small restriction length polymorphisms and one restriction site polymorphism exist between Ddc⁺⁴ and Canton-S DNA. Five of these differences occur in the 5' untranslated leader sequence of the DDC mRNA or in the 4.5 kb of DNA upstream of the transcription start site. Some DNA sequence data have been acquired (Spencer and Hodgetts, unpublished data).