MutMap (Mutation Mapping) is a recently developed efficient and cost-effective genetic approach based on high-throughput next-generation sequencing. MutMap has been used for the first time in rice to map mutations that cause leaf color change and semi-dwarf plant structure.
The mutant lines mostly carry recessive mutations and such mutations do not impact phenotypic alteration. Therefore, the mutant lines need to be self-pollinated to obtain homozygous mutant populations in subsequent generations. Then the mutants with recessive mutation need to be identified based on the phenotypic screening and crossed with the wild type of the same cultivar. The obtained F1 hybrid plants need to be self-crossed to obtain F2 generation. Furthermore, the bulk DNA of the F2 population may be sequenced and mapped against the wild-type cultivar's reference genome to identify SNPs and insertions-deletions that may be associated with the trait. MutMap may be used to rapidly discover desirable genes of agronomic value because of its broad application and low sequencing cost.
The MutMap technique has recently been used in tomatoes to map mutations induced in the Micro-Tom cultivars. A segregating F2 population has been developed by crossing the homozygous mutant line with a wild Micro-Tom, and separate pools of plants showing mutant and wildtype phenotypes have been sequenced with the NGS method to map the causal mutation.

Dr. Md. Monirul Islam
Senior Scientist

Figure. Schematic representation of a typical mutmap strategy exploring next-generation sequencing to identify the causal mutations that resulted in altered phenotype in plants.