Evolution of organismal complexity and origin of novelties during vertebrate history has been widely explored in context of both regulation of gene expression and genome duplication events. A large body of evolutionary developmental (evo-devo) studies has revealed that differences among closely and distantly related animal taxa are associated with differences in the spatial and temporal aspects of gene expression regulation during development (Villar et al. 2014). Still others consider that Evolutionary transitions and diversification of life forms on earth are spurred by drastic expansion in genetic toolkit, accomplished through extensive gene duplications (Ohno 1973; Van de Peer et al. 2009). Several gene duplication mechanisms are suggested to be adapted by nature according to the size of genomic fragment that is getting duplicated thus generating novel genes and so creating genetic diversity over the course of evolution. Duplication events may involve an entire genome, large segments of a genome, individual genes, individual exons, or even specific parts of exons (Betran and Long 2002). Gene duplication originates by three diverse patterns: independent gene duplications, segmental duplications and chromosomal or whole genome duplications.
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