A genomic timescale for the origin of eukaryotes

S. Blair Hedges, Hsiong Chen, Sudhir Kumar, Daniel Y C Wang, Amanda S. Thompson, Hidemi Watanabe

Research output: Contribution to journalArticle

127 Citations (Scopus)

Abstract

Background: Genomic sequence analyses have shown that horizontal gene transfer occurred during the origin of eukaryotes as a consequence of symbiosis. However, details of the timing and number of symbiotic events are unclear. A timescale for the early evolution of eukaryotes would help to better understand the relationship between these biological events and changes in Earth's environment, such as the rise in oxygen. We used refined methods of sequence alignment, site selection, and time estimation to address these questions with protein sequences from complete genomes of prokaryotes and eukaryotes. Results: Eukaryotes were found to evolve faster than prokaryotes, with those eukaryotes derived from eubacteria evolving faster than those derived from archaebacteria. We found an early time of divergence (∼4 billion years ago, Ga) for archaebacteria and the archaebacterial genes in eukaryotes. Our analyses support at least two horizontal gene transfer events in the origin of eukaryotes, at 2.7 Ga and 1.8 Ga. Time estimates for the origin of cyanobacteria (2.6 Ga) and the divergence of an early-branching eukaryote that lacks mitochondria (Giardia) (2.2 Ga) fall between those two events. Conclusions: We find support for two symbiotic events in the origin of eukaryotes: one premitochondrial and a later mitochondrial event. The appearance of cyanobacteria immediately prior to the earliest undisputed evidence for the presence of oxygen (2.4-2.2 Ga) suggests that the innovation of oxygenic photosynthesis had a relatively rapid impact on the environment as it set the stage for further evolution of the eukaryotic cell.

Original languageEnglish (US)
Article number4
JournalBMC Evolutionary Biology
Volume1
DOIs
StatePublished - Sep 12 2001

Fingerprint

eukaryote
Eukaryota
eukaryotic cells
genomics
timescale
Horizontal Gene Transfer
gene transfer
prokaryote
Archaea
Cyanobacteria
prokaryotic cells
cyanobacterium
divergence
Oxygen
Giardia
oxygen
Symbiosis
Eubacteria
Sequence Alignment
Photosynthesis

ASJC Scopus subject areas

  • Medicine(all)
  • Ecology, Evolution, Behavior and Systematics

Cite this

Hedges, S. B., Chen, H., Kumar, S., Wang, D. Y. C., Thompson, A. S., & Watanabe, H. (2001). A genomic timescale for the origin of eukaryotes. BMC Evolutionary Biology, 1, [4]. https://doi.org/10.1186/1471-2148-1-4

A genomic timescale for the origin of eukaryotes. / Hedges, S. Blair; Chen, Hsiong; Kumar, Sudhir; Wang, Daniel Y C; Thompson, Amanda S.; Watanabe, Hidemi.

In: BMC Evolutionary Biology, Vol. 1, 4, 12.09.2001.

Research output: Contribution to journalArticle

Hedges, SB, Chen, H, Kumar, S, Wang, DYC, Thompson, AS & Watanabe, H 2001, 'A genomic timescale for the origin of eukaryotes', BMC Evolutionary Biology, vol. 1, 4. https://doi.org/10.1186/1471-2148-1-4
Hedges SB, Chen H, Kumar S, Wang DYC, Thompson AS, Watanabe H. A genomic timescale for the origin of eukaryotes. BMC Evolutionary Biology. 2001 Sep 12;1. 4. https://doi.org/10.1186/1471-2148-1-4
Hedges, S. Blair ; Chen, Hsiong ; Kumar, Sudhir ; Wang, Daniel Y C ; Thompson, Amanda S. ; Watanabe, Hidemi. / A genomic timescale for the origin of eukaryotes. In: BMC Evolutionary Biology. 2001 ; Vol. 1.
@article{bc0ac39a45e24eb5b3ac5318b67f2ab8,
title = "A genomic timescale for the origin of eukaryotes",
abstract = "Background: Genomic sequence analyses have shown that horizontal gene transfer occurred during the origin of eukaryotes as a consequence of symbiosis. However, details of the timing and number of symbiotic events are unclear. A timescale for the early evolution of eukaryotes would help to better understand the relationship between these biological events and changes in Earth's environment, such as the rise in oxygen. We used refined methods of sequence alignment, site selection, and time estimation to address these questions with protein sequences from complete genomes of prokaryotes and eukaryotes. Results: Eukaryotes were found to evolve faster than prokaryotes, with those eukaryotes derived from eubacteria evolving faster than those derived from archaebacteria. We found an early time of divergence (∼4 billion years ago, Ga) for archaebacteria and the archaebacterial genes in eukaryotes. Our analyses support at least two horizontal gene transfer events in the origin of eukaryotes, at 2.7 Ga and 1.8 Ga. Time estimates for the origin of cyanobacteria (2.6 Ga) and the divergence of an early-branching eukaryote that lacks mitochondria (Giardia) (2.2 Ga) fall between those two events. Conclusions: We find support for two symbiotic events in the origin of eukaryotes: one premitochondrial and a later mitochondrial event. The appearance of cyanobacteria immediately prior to the earliest undisputed evidence for the presence of oxygen (2.4-2.2 Ga) suggests that the innovation of oxygenic photosynthesis had a relatively rapid impact on the environment as it set the stage for further evolution of the eukaryotic cell.",
author = "Hedges, {S. Blair} and Hsiong Chen and Sudhir Kumar and Wang, {Daniel Y C} and Thompson, {Amanda S.} and Hidemi Watanabe",
year = "2001",
month = "9",
day = "12",
doi = "10.1186/1471-2148-1-4",
language = "English (US)",
volume = "1",
journal = "BMC Evolutionary Biology",
issn = "1471-2148",
publisher = "BioMed Central",

}

TY - JOUR

T1 - A genomic timescale for the origin of eukaryotes

AU - Hedges, S. Blair

AU - Chen, Hsiong

AU - Kumar, Sudhir

AU - Wang, Daniel Y C

AU - Thompson, Amanda S.

AU - Watanabe, Hidemi

PY - 2001/9/12

Y1 - 2001/9/12

N2 - Background: Genomic sequence analyses have shown that horizontal gene transfer occurred during the origin of eukaryotes as a consequence of symbiosis. However, details of the timing and number of symbiotic events are unclear. A timescale for the early evolution of eukaryotes would help to better understand the relationship between these biological events and changes in Earth's environment, such as the rise in oxygen. We used refined methods of sequence alignment, site selection, and time estimation to address these questions with protein sequences from complete genomes of prokaryotes and eukaryotes. Results: Eukaryotes were found to evolve faster than prokaryotes, with those eukaryotes derived from eubacteria evolving faster than those derived from archaebacteria. We found an early time of divergence (∼4 billion years ago, Ga) for archaebacteria and the archaebacterial genes in eukaryotes. Our analyses support at least two horizontal gene transfer events in the origin of eukaryotes, at 2.7 Ga and 1.8 Ga. Time estimates for the origin of cyanobacteria (2.6 Ga) and the divergence of an early-branching eukaryote that lacks mitochondria (Giardia) (2.2 Ga) fall between those two events. Conclusions: We find support for two symbiotic events in the origin of eukaryotes: one premitochondrial and a later mitochondrial event. The appearance of cyanobacteria immediately prior to the earliest undisputed evidence for the presence of oxygen (2.4-2.2 Ga) suggests that the innovation of oxygenic photosynthesis had a relatively rapid impact on the environment as it set the stage for further evolution of the eukaryotic cell.

AB - Background: Genomic sequence analyses have shown that horizontal gene transfer occurred during the origin of eukaryotes as a consequence of symbiosis. However, details of the timing and number of symbiotic events are unclear. A timescale for the early evolution of eukaryotes would help to better understand the relationship between these biological events and changes in Earth's environment, such as the rise in oxygen. We used refined methods of sequence alignment, site selection, and time estimation to address these questions with protein sequences from complete genomes of prokaryotes and eukaryotes. Results: Eukaryotes were found to evolve faster than prokaryotes, with those eukaryotes derived from eubacteria evolving faster than those derived from archaebacteria. We found an early time of divergence (∼4 billion years ago, Ga) for archaebacteria and the archaebacterial genes in eukaryotes. Our analyses support at least two horizontal gene transfer events in the origin of eukaryotes, at 2.7 Ga and 1.8 Ga. Time estimates for the origin of cyanobacteria (2.6 Ga) and the divergence of an early-branching eukaryote that lacks mitochondria (Giardia) (2.2 Ga) fall between those two events. Conclusions: We find support for two symbiotic events in the origin of eukaryotes: one premitochondrial and a later mitochondrial event. The appearance of cyanobacteria immediately prior to the earliest undisputed evidence for the presence of oxygen (2.4-2.2 Ga) suggests that the innovation of oxygenic photosynthesis had a relatively rapid impact on the environment as it set the stage for further evolution of the eukaryotic cell.

UR - http://www.scopus.com/inward/record.url?scp=1642534172&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1642534172&partnerID=8YFLogxK

U2 - 10.1186/1471-2148-1-4

DO - 10.1186/1471-2148-1-4

M3 - Article

VL - 1

JO - BMC Evolutionary Biology

JF - BMC Evolutionary Biology

SN - 1471-2148

M1 - 4

ER -