Monomorphic molecular markers are as informative as polymorphic molecular markers

Abstract

Molecular markers have been assisting breeders in crop improvement. Judicious integration of molecular markers with conventional breeding practices has contributed numerous improved varieties. In the process of MAS, monomorphic markers are most often eliminated from further investigations assuming that they are noninformative. In this study, efforts were made to elucidate information from monomorphic markers. Twenty rice genotypes contrasting for grain zinc content were selected. Specific markers were designed to the already reported genes associated with micronutrient transport from soil to grain. Among designed markers, only OsZIP6c and OsZIP3b were polymorphic and Single-Marker Analysis revealed that OsZIP6c was associated with culm zinc content. Sequencing of amplicons of six markers including four monomorphic markers revealed that nucleotide variations were present in monomorphic markers as well. SMA for nucleotide variations revealed that OsZIP5b, a monomorphic marker on agarose, contained nucleotide changes significantly associated with grain zinc content. This clearly demonstrates that monomorphic markers are as informative as polymorphic markers and should not be eliminated from the study.