Chimeric organization of two genes for the soybean mitochondrial ATPase subunit 6.

There are two copies of the ATPase subunit 6 (atp6) gene in the soybean mitochondrial genome which differ in their gene organization but share extensive homology with the maize atp6 gene except at their 5' ends. The two soybean genes are chimeric, containing regions with homology to other known mitochondrial genes at their 5' ends. Sequences homologous to the cytochrome oxidase subunit II (coxII) are located in one copy and sequences homologous to the ATPase subunit 9 (atp9) gene are located in the other copy, both of which contain methionine (ATG) codons that are in-frame with the remainder of the atp6 open reading frame. At least the copy of atp6 that contains the coxII sequence at its 5' end is abundantly transcribed to give an RNA of approximately 1,200 nucleotides.