Data Generation

The triplicated and quadruplicated human gene families residing on four paralogons ( Hsa 2/7/12/17, Hsa 4/5/8/10, Hsa 1/2/8/20 and Hsa 1/6/9/19) were identified by chromosomal scanning using Ensembl and UCSC genome browsers (Hubbard al., 2002). The closest putative orthologous sequences of the human proteins in other species were obtained using BLASTP in the Ensembl genome browser (Clamp et al., 2003; Hubbard et al.,2002) and enrichment of data was conducted by using protein database available at the National Center for Biotechnology Information (Hughes et al., 2001a; Johnson et al., 2008) and the Joint Genome Institute (http://www.jgi.doe.gov/). 

Amino acid sequences were aligned using a multiple sequence alignment tool CLUSTAL-W with default parameter (Thompson et al., 1994). The phylogenetic analysis was performed by reconstructing neighbor joining (NJ) (Russo et al., 1996; Saitou and Nei, 1987) and Maximum Likelihood (Whelan and Goldman, 2001) trees using MEGA version 5 (Kumar et al., 2008).  The co-duplicated groups were detected through topology comparison approach and reflect the branching pattern of phylogenetic trees. The tree topologies of gene families were compared to validate consistency in duplication events (Zhang and Nei, 1996). The age estimates of duplication events of multigene families residing on each paralogon were evaluated using relative dating approach. 

Figure 1: Flow of Data generation

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