美國科學(xué)家在１３日出版的新一期《科學(xué)》雜志上報(bào)告說，他們從生活在６８００萬年前的暴龍的化石中成功測定出了古老的膠原蛋白,，這是化石分析領(lǐng)域的一大技術(shù)突破，同時(shí)蛋白分析結(jié)果也進(jìn)一步佐證了鳥類起源于恐龍的進(jìn)化理論,。
這一暴龍化石是２００３年在美國蒙大拿州發(fā)現(xiàn)的,。北卡羅來納州立大學(xué)古生物學(xué)家瑪麗·施魏策爾等人此前就曾在該暴龍的腿骨化石中發(fā)現(xiàn)了軟組織存在。此次她與哈佛大學(xué)醫(yī)學(xué)院等機(jī)構(gòu)的研究合作者進(jìn)一步發(fā)現(xiàn),，軟組織中包含有古老的膠原蛋白,，這是骨骼中的一種纖維狀蛋白質(zhì)。
施魏策爾說,，對暴龍腿骨化石軟組織進(jìn)行的初步分子分析表明,，其中很可能保存了暴龍?jiān)嫉鞍踪|(zhì)的片段。之后他們利用先進(jìn)的質(zhì)譜測定方法,，成功測序出了組成骨膠原蛋白的氨基酸堿基序列,，進(jìn)一步證實(shí)了蛋白質(zhì)的存在。他們認(rèn)為,，這一結(jié)果將改變?nèi)藗儗４娴目捶ā，F(xiàn)代化石理論認(rèn)為,，蛋白質(zhì)這樣的原始有機(jī)物質(zhì)不可能在如此長的時(shí)間跨度內(nèi)保存下來,。
另外，研究人員將暴龍膠原蛋白的氨基酸堿基序列與現(xiàn)代物種的氨基酸堿基序列對比后發(fā)現(xiàn),，暴龍的序列與雞,、青蛙和蠑螈的序列有類似之處。施魏策爾說,，與雞的序列類似進(jìn)一步證明了現(xiàn)代鳥類與恐龍之間的進(jìn)化關(guān)系,。
部分英文原文：
Science 13 April 2007:
Vol. 316. no. 5822, pp. 280 - 285
DOI: 10.1126/science.1137614
Reports
Protein Sequences from Mastodon and Tyrannosaurus Rex Revealed by Mass Spectrometry
John M. Asara,1,2* Mary H. Schweitzer,3 Lisa M. Freimark,1 Matthew Phillips,1 Lewis C. Cantley1,4
Fossilized bones from extinct taxa harbor the potential for obtaining protein or DNA sequences that could reveal evolutionary links to extant species. We used mass spectrometry to obtain protein sequences from bones of a 160,000- to 600,000-year-old extinct mastodon (Mammut americanum) and a 68-million-year-old dinosaur (Tyrannosaurus rex). The presence of T. rex sequences indicates that their peptide bonds were remarkably stable. Mass spectrometry can thus be used to determine unique sequences from ancient organisms from peptide fragmentation patterns, a valuable tool to study the evolution and adaptation of ancient taxa from which genomic sequences are unlikely to be obtained.
1 Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
2 Department of Pathology, Harvard Medical School, Boston, MA 02115, USA; North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA; and Museum of the Rockies, Montana State University, Bozeman, MT 59717, USA.
3 Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA.
4 Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
* To whom correspondence should be addressed. E-mail: [email protected]
