Host: Abstracts of Annual Meeting of the Geochemical Society of Japan
Name : Abstracts of Annual Meeting of the Geochemical Society of Japan
Number : 67
Date : November 12, 2020 - November 26, 2020
Pages 64-
Steroids are indispensable components of the eukaryotic cellular membrane and have important roles in the process of endocytosis. Steroids are characteristic of eukaryotic organisms and hence have been utilized as biomarkers for eukaryotes in the Precambrian geological record. It is generally inferred that steroids biosynthesis evolved within eukaryotes, while the steroid biosynthesis in a small number of bacteria is a result of horizontal gene transfers from eukaryotes. However, more bacteria have been found to possess a steroid biosynthesis pathway and the traditional understanding of the steroid evolution is now called into question.Our current study suggests that the entire eukaryotic steroid biosynthesis pathway is derived from bacteria. Almost all genes that are involved in the steroid biosynthesis up to cholesterol are inferred to have evolved within the bacterial domain. However, the evolutionary trajectory for individual genes seems to be different from one another. Hence, the evolution of the eukaryotic isoprenoid biosynthesis pathway is inferred to have been a multi-step process that was triggered by the rise of molecular oxygen at Great Oxidation Event.
