Duplications of a variety of genes relative to chickens or humans, including growth hormone and caspase-3, the latter of which is associated with the induction of apoptosis, and gene family expansions, including of the PAK3 and PHF7 genes, which are involved in dendritic plasticity and transcriptional regulation, respectively, were also found in the zebra finch genome [3]. Interestingly, multiple duplications of the PHF7 gene seem to have occurred independently in zebra finches and chickens, suggesting that some aspects of transcriptional regulation may have been under evolutionary pressure in avian species. Whereas these avian lineages have groups of 17 and 18 PHF7genes, respectively, the human genome has been shown to contain only one PHF7 gene [3].