TY - JOUR
T1 - Debating Eukaryogenesis—Part 2
T2 - How Anachronistic Reasoning Can Lure Us into Inventing Intermediates
AU - Speijer, Dave
N1 - Funding Information: The author would like to thank generations of students for asking difficult questions, two outstanding anonymous reviewers for their input, and Andrew Moore for long-standing support. Publisher Copyright: © 2020 The Authors. BioEssays published by Wiley Periodicals, Inc. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/5/1
Y1 - 2020/5/1
N2 - Eukaryotic origins are inextricably linked with the arrival of a pre-mitochondrion of alphaproteobacterial-like ancestry. However, the nature of the “host” cell and the mode of entry are subject to heavy debate. It is becoming clear that the mutual adaptation of a relatively simple, archaeal host and the endosymbiont has been the defining influence at the beginning of the eukaryotic lineage; however, many still resist such symbiogenic models. In part 1, it is posited that a symbiotic stage before uptake (“pre-symbiosis”) seems essential to allow further metabolic integration of the two partners ending in endosymbiosis. Thus, the author argued against phagocytic mechanisms (in which the bacterium is prey or parasite) as the mode of entry. Such positions are still broadly unpopular. Here it is explained why. Evolutionary thinking, especially in the case of eukaryogenesis, is still dominated by anachronistic reasoning, in which highly derived protozoan organisms are seen as in some way representative of intermediate steps during eukaryotic evolution, hence poisoning the debate. This reasoning reflects a mind-set that ignores that Darwinian evolution is a fundamentally historic process. Numerous examples of this kind of erroneous reasoning are given, and some basic precautions against its use are formulated. Also see the video abstract here https://youtu.be/ekqtNleVJpU.
AB - Eukaryotic origins are inextricably linked with the arrival of a pre-mitochondrion of alphaproteobacterial-like ancestry. However, the nature of the “host” cell and the mode of entry are subject to heavy debate. It is becoming clear that the mutual adaptation of a relatively simple, archaeal host and the endosymbiont has been the defining influence at the beginning of the eukaryotic lineage; however, many still resist such symbiogenic models. In part 1, it is posited that a symbiotic stage before uptake (“pre-symbiosis”) seems essential to allow further metabolic integration of the two partners ending in endosymbiosis. Thus, the author argued against phagocytic mechanisms (in which the bacterium is prey or parasite) as the mode of entry. Such positions are still broadly unpopular. Here it is explained why. Evolutionary thinking, especially in the case of eukaryogenesis, is still dominated by anachronistic reasoning, in which highly derived protozoan organisms are seen as in some way representative of intermediate steps during eukaryotic evolution, hence poisoning the debate. This reasoning reflects a mind-set that ignores that Darwinian evolution is a fundamentally historic process. Numerous examples of this kind of erroneous reasoning are given, and some basic precautions against its use are formulated. Also see the video abstract here https://youtu.be/ekqtNleVJpU.
KW - anachronisms
KW - eukaryogenesis
KW - mitochondria
KW - origin of sex
KW - reactive oxygen species
KW - symbiogenesis
UR - http://www.scopus.com/inward/record.url?scp=85081573087&partnerID=8YFLogxK
U2 - https://doi.org/10.1002/bies.201900153
DO - https://doi.org/10.1002/bies.201900153
M3 - Article
C2 - 32157725
SN - 0265-9247
VL - 42
JO - BioEssays
JF - BioEssays
IS - 5
M1 - 1900153
ER -