Adkins R M, Nekrutenko A, Li W H
Biology Department, University of Massachusetts, USA.
Mol Biol Evol. 2001 Jan;18(1):55-60. doi: 10.1093/oxfordjournals.molbev.a003719.
Unlike other mammals, Old World primates have five growth hormone-like genes that are highly divergent at the amino acid level from the single growth hormone genes found in nonprimates. Additionally, there is a change in the interaction of growth hormone with its receptor in humans such that human growth hormone functions in nonprimates, whereas nonprimate growth hormone is ineffective in humans. A Southern blotting analysis of the genome of a prosimian, Galago senegalensis, revealed a single growth hormone locus. This single gene was PCR-amplified from genomic DNA and sequenced. It has a rate of nonsynonymous nucleotide substitution less than one fourth that of the human growth hormone gene, while the rates of synonymous substitution in the two species are less different. Human and rhesus monkey growth hormones exhibit variation at a number of amino acid residues that can affect receptor binding. The galago growth hormone is conservative at each of these sites, indicating that this growth hormone is functionally like nonprimate growth hormones. These observations indicate that the amplification and rapid divergence of primate growth hormones occurred after the separation of the higher primate lineage from the galago lineage.
与其他哺乳动物不同，旧世界灵长类动物有五个类生长激素基因，这些基因在氨基酸水平上与非灵长类动物中发现的单个生长激素基因高度不同。此外，人类生长激素与其受体的相互作用发生了变化，以至于人类生长激素在非灵长类动物中起作用，而非灵长类动物的生长激素在人类中无效。对一种原猴（塞内加尔婴猴）的基因组进行的Southern印迹分析揭示了一个单一的生长激素基因座。从基因组DNA中PCR扩增并测序了这个单一基因。它的非同义核苷酸替换率不到人类生长激素基因的四分之一，而这两个物种的同义替换率差异较小。人类和恒河猴的生长激素在一些可能影响受体结合的氨基酸残基上存在变异。婴猴生长激素在这些位点上都是保守的，这表明这种生长激素在功能上类似于非灵长类动物的生长激素。这些观察结果表明，灵长类动物生长激素的扩增和快速分化发生在高等灵长类动物谱系与婴猴谱系分离之后。
