title: Classification of Normal and Male-Sterile Cytoplasms in Maize. II. Electrophoretic Analysis of DNA Species in Mitochondria.
abstract: Mitochondrial DNA preparations were made from 31 maize lines carrying different sources of cytoplasm in the same nuclear genetic background. The DNAs were analyzed by agarose gel electrophoresis. A number of discrete low molecular weight bands were present in all lines. However, only four different DNA banding patterns were observed. These were correlated with the N, T, S and C cytoplasms defined by nuclear fertility restorer genes. Of the 31 cytoplasmic sources examined, six possessed DNA species characteristic of N cytoplasms, four possessed DNA species characteristic of T cytoplasm, 19 possessed DNA species characteristic of S cytoplasm and two possessed DNA species characteristic of C cytoplasm. This classification is in complete agreement with that based on mitochondrial translation products reported in the accompanying paper. No within-group heterogeneity was observed in the DNA banding patterns, indicating a lack of cytoplasmic variation within the four cytoplasmic groups. Attributes of the various methods available for classifying maize cytoplasms are compared and discussed.
authors.affiliation: Plant Breeding Institute, Maris Lane, Trumpington, Cambridge CB2 2LQ, England.
authors.forename: R J
authors.initials: RJ
authors.lastname: Kemble
authors.forename: R E
authors.initials: RE
authors.lastname: Gunn
authors.forename: R B
authors.initials: RB
authors.lastname: Flavell