Different molecular or marked-assisted breeding methods are marker-assisted selection, marker-assisted backcrossing, marker-assisted recurrent selection, and genome wide selection. Molecular breeding has been developed to mimic the essential feature of natural evolution which is diversity. The key limitation to molecular breeding is the lack of biochemical understanding of any particular traits such as color, fragrance and flavor of crops. Genome evolution is usually viewed through the lens of growth in size and complexity over time, exemplified by plants and animals. Functional genomics is inundating the pharmaceutical industry with large numbers of potential gene targets from several sources such as gene expression profiling experiments (DNA microchips, proteomics) or database mining. Genome editing technologies are powerful tools for studying gene function and for crop improvement which rely on engineered endonucleases to generate double stranded breaks at target loci. The greatest contribution of QTL mapping to plant breeding will be the basic understanding of the genetic architecture of quantitative traits, thereby relating specific genetic loci with the biological mechanisms associated with desirable phenotypes. QTL mapping provides a starting point for dissecting complex traits into their component alleles and it may help to quantify relative impacts of alleles on the traits and locates genomic regions responsible for marker-trait association, and finally, it may provide a foundation of marker-assisted selection which expedites the breeding process given the proper estimation of position and the effects of QTLs. SDRs form a structural motif for enzymes that catalyze a wide variety or reactions, even if sequences identify often is low. In all taxa (bacteria, plants, insects, vertebrates), members of SDR superfamily are known. The number of SDR members increases considerably every year, but the number of SDR families starts to converge. The SDR superfamily is one of the largest known protein families and comprises thousands of members found in species ranging from bacteria to humans. SDR involvement has been demonstrated in a variety of primary and secondary metabolisms. The multiplicity of SDRs in plant kingdom is mainly explained by the diversification of large families involved in different secondary metabolism pathways, suggesting that the chemical diversification that accompanied the emergence of vascular plants acted as a driving force for SDR evolution. SDR families are either involved in the secondary metabolism routes (terpenoids, alkaloids, phenolics) or participate in developmental processes (hormone biosynthesis or catabolism, flower development). Proteins are essential parts of organisms and participate in virtually every process within cells. Peptides are small polymers of amino acid monomers that are bonded together and distinguished from proteins by their size. Peptides are used in clinical research to examine the inhibition of cancer proteins and other diseases. Some advantages of peptides are high potency, high selectivity, broad range of targets, low toxicity, low accumulation in tissue, and high chemical and biological diversity.
