Controlled hydroxyapatite biomineralization in an ~810 million-year-old unicellular eukaryote.
Controlled hydroxyapatite biomineralization in an ~810 million-year-old unicellular eukaryote.
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DOI：
10.1126/sciadv.1700095
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发表时间：
2017-06
期刊：
影响因子：
13.6
通讯作者：
Tosca N
中科院分区：
文献类型：
--
作者：
Cohen PA;Strauss JV;Rooney AD;Sharma M;Tosca N
新的分析表明，来自育空地区的8.11亿年前的微化石是真核生物矿化作用的最古老证据。生物矿化标志着真核生物最重要的进化里程碑之一，但其在化石记录中的根源仍然模糊不清。本文报道了加拿大育空地区十五英里群新元古代规模微体化石中受控真核生物矿化的晶体学和地球化学证据。高分辨率透射电子显微镜显示，微化石是由纤维状羟基磷灰石晶体的分层组织交织网络构成的，每个纤维状羟基磷灰石晶体沿[001]方向沿着延伸，表明生物控制微结构结晶。新的Re-Os地质年代学数据显示，富含有机质的页岩直接位于含化石的石灰岩之下，其年龄小于8.107亿± 630万年。这些沉积岩的矿物学和地球化学变化表明，全球海洋氧化还原条件的动态，增强了当地的限制，可能会导致溶解磷酸盐的孔隙和底部沃茨的十五英里盆地和促进必要的地球化学条件的钙磷酸盐生物矿化的到来。
New analyses show that 811 million-year-old microfossils from the Yukon are the oldest evidence of eukaryotic biomineralization. Biomineralization marks one of the most significant evolutionary milestones among the Eukarya, but its roots in the fossil record remain obscure. We report crystallographic and geochemical evidence for controlled eukaryotic biomineralization in Neoproterozoic scale microfossils from the Fifteenmile Group of Yukon, Canada. High-resolution transmission electron microscopy reveals that the microfossils are constructed of a hierarchically organized interwoven network of fibrous hydroxyapatite crystals each elongated along the [001] direction, indicating biological control over microstructural crystallization. New Re-Os geochronological data from organic-rich shale directly below the fossil-bearing limestone constrain their age to <810.7 ± 6.3 million years ago. Mineralogical and geochemical variations from these sedimentary rocks indicate that dynamic global marine redox conditions, enhanced by local restriction, may have led to an increase in dissolved phosphate in pore and bottom waters of the Fifteenmile basin and facilitated the necessary geochemical conditions for the advent of calcium phosphate biomineralization.