近日，中国海洋大学李三忠团队研究了从软组织转移到双壳的固醇：分子古生物学的新痕迹。2025年11月6日出版的《地质学》杂志发表了这项成果。
以化学共生为基础的无脊椎动物群落主导着深海热液喷口和甲烷渗漏，但在化石记录中检测化学共生并追踪其地质历史演变的可靠方法仍然缺乏。
研究组分析了寄生于甲烷营养或硫营养共生体的双壳类深海生物（包括活壳和空壳）的贝壳脂质库存。所有物种都有一套共同的脂质，这些脂质主要来自外部异养环境，除了深叶藻素本身的胆固醇和胆甾烷醇类。这些甾醇的δ13C值低至83‰，表明这些化合物来源于动物。
这种转移不依赖于共生体是甲烷营养型还是硫营养型，也不依赖于这些动物体内胆固醇和胆甾烷醇类的不同生物合成途径。这一发现为分子古生物学开辟了新前景——通过利用这些化合物的来源特异性与成岩稳定性，将能追溯化学共生现象及其在化石记录中的演化历程，尤其适用于深海偏顶蛤类，并有望扩展至其他后生动物类群。
附：英文原文
Title: Sterols transferred from soft tissues to bivalve shells: A new tracer of molecular paleontology
Author: Hongxiang Guan, Steffen Kiel, Xiaoyan Xu, Jiachen Fan, Yi Zhang, Xiaoming Miao, Hangyu Nan, Nengyou Wu, Sanzhong Li
Issue&Volume: 2025-11-06
Abstract: Chemosymbiosis-based invertebrate communities dominate deep-sea hydrothermal vents and methane seeps, but reliable methods for detecting chemosymbiosis in the fossil record and tracing its evolution into the geologic past are still lacking. Here, we investigate the lipid inventory of shells of four seep-dwelling bivalve species (from both live specimens and empty shells) hosting either methanotrophic or thiotrophic symbionts. All species share a common suite of lipids that are mostly derived from external heterotrophic sources, except for cholesterol and cholestanols in bathymodiolin mussels. The δ13C values of these sterols as low as 83‰ indicate an origin of these compounds from the animal. The transfer was independent of the symbionts being methanotrophic or thiotrophic and thus of the distinct biosynthetic pathways for cholesterol and cholestanol of these animals. This finding opens a new prospect for molecular paleontology by taking advantage of the source specificity and diagenetic stability of these compounds. It could allow tracing chemosymbiosis and its evolution into the fossil record, in particular in bathymodiolin mussels, and potentially also in other metazoan groups.
DOI: 10.1130/G53933.1
Geology：《地质学》，创刊于1973年。隶属于美国地质学会，最新IF：6.324
官方网址：https://pubs.geoscienceworld.org/geology
投稿链接：https://geology.msubmit.net/cgi-bin/main.plex