Nucleotide sequences encoding glycinin B4 polypeptide of the cultivated soybean Glycine max and its presumed wild-type ancestor Glycine soja in connection with the origin of cultivated soybean

Nucleotide sequences of cDNAs encoding soybean glycinin B4 polypeptide were compared in three soybean cultivars and two plant introductions of wild soybean Glycine soja. Only two nucleotide substitutions were found in three cultivars G. max, as compared with G. max and G. soja having nucleotide sequences which contain four nucleotide substitutions. These data serve as additional evidence, at molecular level, indicating the origin of G. max from G. soja. On the other hand, the time period required for four nucleotide substitutions' accumulation, as calculated from parameters of molecular evolution of 11S globulins, is much longer than the term having passed after soybean domestication.