Miller S L, Lazcano A
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0317, USA.
J Mol Evol. 1995;41:689-92. doi: 10.1007/BF00173146.
A high-temperature origin of life has been proposed, largely for the reason that the hyperthermophiles are claimed to be the last common ancestor of modern organisms. Even if they are the oldest extant organisms, which is in dispute, their existence can say nothing about the temperatures of the origin of life, the RNA world, and organisms preceding the hyperthermophiles. There is no geological evidence for the physical setting of the origin of life because there are no unmetamorphosed rocks from that period. Prebiotic chemistry points to a low-temperature origin because most biochemicals decompose rather rapidly at temperatures of 100 degrees C (e.g., half-lives are 73 min for ribose, 21 days for cytosine, and 204 days for adenine). Hyperthermophiles may appear at the base of some phylogenetic trees because they outcompeted the mesophiles when they adapted to lower temperatures, possibly due to enhanced production of heat-shock proteins.
有人提出生命起源于高温，主要原因是嗜热菌被认为是现代生物的最后一个共同祖先。即便它们是现存最古老的生物（这一点存在争议），它们的存在也无法说明生命起源、RNA世界以及嗜热菌之前的生物所处时期的温度情况。由于没有那个时期未变质的岩石，所以没有关于生命起源物理环境的地质证据。前生物化学表明生命起源于低温，因为大多数生物化学物质在100摄氏度时会相当迅速地分解（例如，核糖的半衰期为73分钟，胞嘧啶为21天，腺嘌呤为204天）。嗜热菌可能出现在某些系统发育树的基部，因为当它们适应较低温度时，可能由于热休克蛋白产量增加，从而在与嗜温菌的竞争中胜出。
