Nucleotide sequence of the wheat mitochondrial gene for subunit I of cytochrome oxidase.

The sequence of the wheat mltochondrial gene for cytochrome oxidase subunit I (COI) predicts a hydrophoblc protein of 524 amlno acids that shows strong similarity to those of maize (99% nucleotide identity), soybean (94%) and Oenothera (93%). Nine of the 30 nucleotide differences seen between the wheat and maize COI genes (arrowheads) lead to amlno acid substitutions, many of which occur at the carboxy-terminus. The wheat COI protein is predicted to be four residues shorter than that of maize. No sequence conservation Is observed downstream of the coding region. However, upstream of the COI gene, scattered homology is seen between wheat and maize, and at a lower level with soybean (boxed). A 29bp direct repeat precedes that block in wheat (underlined). The wheat COI gene Is a single-copy gene and RNA blot analysis shows a single major transcript of approximately 2.2kb. We thank L.A. Grivell for the yeast COI gene probe used to Isolate the wheat gene and acknowledge the support of MRC and NSERC Canada.