title: Comment on "Positive selection of tyrosine loss in metazoan evolution".
abstract: Tan et al. (Reports, 25 September 2009, p. 1686) argued that loss of tyrosine residues from proteins in metazoans was driven by positive selection to remove potentially deleterious phosphorylation sites. We challenge this hypothesis, providing evidence that the high guanine-cytosine (GC) content of metazoan genomes was the primary driver in the loss of tyrosine residues.
authors: MOE Key Laboratory of Contemporary Anthropology and Center for Evolutionary Biology, School of Life Sciences, Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, China.
authors: Zhixi
authors: Z
authors: Su
authors: Wei
authors: W
authors: Huang
authors: Xun
authors: X
authors: Gu