**7.1 Concept**

Exploitation of gene banks for efficient utilization depends on the knowledge of genetic diversity, in general, and allelic diversity at candidate gene(s) of interest, in particular. Hence, allele mining seems to be a promising in characterization of genetic diversity or allelic/genic diversity among the accessions of the collection in terms of its utility for improving a target trait (Kaur *et al*., 2008). The availability of sequence and sequence variation that affects the plant phenotype is of utmost importance for the utilization of genetic resources in crop improvement (Graner, 2006).

The existing allelic diversity in any crop species is caused by mutations, the evolutionary driving force (Kumar *et al*., 2010). Mutations create new alleles or cause variations in the existing allele and allelic combinations. They take place in coding and non-coding regions of the genome either as single nucleotide polymorphism (SNP) or as insertion and deletion (InDel). As far it is known, there is no cited literatures on the effect of mutations on transcript synthesis and accumulation which in turn alter the trait expression in 5′ UTR including promoter, introns and 3′ UTR in the genome of soybean. In coding region, it may have tremendous effect on the phenotype by altering the encoded protein structure and/or function. For example, the AtAHASL protein encoded by *csr1-2* differs from the native AtAHASL protein by one amino acid substitution of a serine with an asparagine at residue 653 (S653N) which results in tolerance to imidazolinone containing herbicides. Besides the altered herbicide binding, the protein retains its biological function in the plant. Soybean line CV127 is tolerant to herbicides that contain imidazolinone. The another example is the mutations in soybean microsomal omega-3 fatty acid desaturase genes which resulted in reduce of linolenic acid concentration in soybean seeds (Bilyeu *et al*., 2005). Alternatively, several studies suggested that many diseases resistant alleles like soybean aphid [*Aphis glycines* Matsumura (Hemiptera: Aphididae)] resistance like *Rag1* from Germplasm collection (Kim *et al.*, 2010), brown Stem Rot resistance like *Rbs1* and *Rbs3* from soybean lines L78-4049 and PI 437.833, and PI 84946-2 (Eathington *et al*., 1995; Klos *et al.,* 2000), soybean cyst nematode (SCN) resistance genes like *rhg*1 and *Rhg*4 *from soybean* lines PI 88788, PI 437.654, Peking, PI90763 and PI209332, sudden death syndrome (SDS) resistance like Rfs1, rfs2, and rft from soybean lines PI 437654 ( Meksem *et al*., 2001).
