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Molecular evolution of the avian growth hormone gene and comparison with its mammalian counterpart
Author(s) -
BUGGIOTTI L.,
PRIMMER C. R.
Publication year - 2006
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2005.01042.x
Subject(s) - biology , molecular evolution , evolutionary biology , gene , signal peptide , phylogenetics , growth hormone , sequence (biology) , genetics , peptide , zoology , hormone , peptide sequence , endocrinology , biochemistry
The molecular evolution of all available avian growth hormone ( GH ) gene sequences was investigated using both maximum‐likelihood and parsimony methods, and the patterns compared to those found in mammals. In contrast to the rapid bursts of evolution observed for mammalian GH , the evolutionary rate of the avian GH mature peptide appears to have been more constant. However several positively selected sites were identified at functionally important positions in the avian signal peptide by the site‐specific likelihood method. This implies that sequence variation in the avian GH signal peptide may be adaptive, although more conservative parsimony methods failed to confirm this. Nevertheless, the differing patterns of avian and mammalian GH signal peptide molecular evolution are consistent with the apparently differing roles of GH in controlling growth in these taxonomic groups and support the hypothesis that signal peptide sequence variation may in fact be the basis for increased functional complexity.