Framework : Eukaryogenesis and Evolution

I Eukaryogenesis

The time of origin of the Last Eukaryotic Common Ancestor is controversial. One late origin of the extant eukaryotic diversity suggests LECA arose 1.4-1.2 Gya. However, sterol biomarkers, a red algae fossil, and acritarch fossils suggest an arrival earlier than 1.45 Gya. This discrepancy can be explained if < 1.45 Gya Acritarchs are pre-LECA organisms or extinct prokaryotes. Therefore, Acritarchs may provide clues to past extinction events and eukaryogenesis.

The existence of multiple primary, secondary, tertiary, and quartenary symbioses creates a complicated scenario of evolution via infectious speciation events. Understanding the primary symbiotic events is necessary for the elucidation of the subsequent heirarchial processes.

My working model of eukaryocyte evolution incorporates symbioses and DNA transposons as differentiation factors resposible for the diversification of eukaryotic kingdoms. An historical perspective that separates the growth of the bush of life into Primary, Secondary, Tertiary, and Quartenary Symbiotic Periods may simplify the understanding of the maize like pathways of evolution.

I. Primary Prokaryote Symbiosis Period : Evolution of LECA, Amorphea, and Diaphoretickes

II. Secondary Eukaryote + Eukaryote Symbiosis Period : Evolution of Euglenozoa and SAR

III. Tertiary Eukaryote Symbiosis Period

IV. Quartenary Eukaryote Symbiosis Period

V. Metazoan Evolution involving transfers of embedded Transposable Elements . ( ie.; birds flying with attached snails containing parasites with transposon containing viruses. Or, flying insects with parasites and transposon containing viruses that influence distant speciation events ) Combinations of DNA Transposons are responsible radiation events in Eukaryotes. A history of these elements helps elucidate major mechanisms of eurkaryotic macroevolution.

Eukaryote Classes
Amorphea	Opisthokonta	Metazoa Choanomonada Fungi
	Amoebozoa	Tubulinea Mycetozoa
		Apusomonada
		Breviata
	Excavata	Malawinomas Metamonada Discoba
Diaphoretickes	CCTH	Cryptophyceae Centrohelida Telonemia Haptophyta
	SAR	Cercoza Foraminifera Radiolaria Alveolata Stamenopiles
	Archaeplastids	Glaucophyta Rhodophyceae Chloroplastida

Nonclassified Groups and Genera - Somewhere in this list lurks the vestigial form of the last eukaryotic common ancestor. Currently LECA appears to be an close ancestor of both Collodictyon and Breviata. The ameboid species are particularly difficult to classify because they could be amoebazoa, fungi, spermatia, heterolobosea, trimetia, apicomplexa or yet to be classified orders.

References :

A tree of Eukaryotes

Intermediary Metabolism in Protists: a Sequence-based View of Facultative Anaerobic Metabolism in Evolutionarily Diverse Eukaryotes

A late origin of the extant eukaryotic diversity: divergence time estimates using rare genomic changes

Genomic Analysis Indicates the Presence of an Asymmetric Bilayer Outer Membrane in Planctomycetes and Verrucomicrobia

The origin and early evolution of eukaryotes in the light of phylogenomics.

Phylogenomic evidence for a common ancestor of mitochondria and the SAR11 clade.

Control systems for membrane fusion in the ancestral eukaryote; evolution of tethering complexes and SM proteins.

The origin of the eukaryotic cell: A genomic investigation

Autophagy in protists

An archaeal origin for the actin cytoskeleton: Implications for eukaryogenesis

Components of Coated Vesicles and Nuclear Pore Complexes Share a Common Molecular Architecture

A congruent phylogenomic signal places eukaryotes within the Archaea

Endosymbiosis and the Origin of Eukaryotes

Protozoa, Chromista, and the eukaryote root.

The Proterozoic Fossil Record of Heterotrophic Eukaryotes SUSANNAH M. PORTER .

The evolution and distribution of life in the Precambrian eon-Global perspective and the Indian record M SHARMA* and Y SHUKLA

record of Obruchevella from the Mesoproterozoic sediments of India by Veeru Singh

Evolutionary position of breviate amoebae and the primary eukaryote divergence Marianne A. Minge,, Jeffrey D. Silberm, Russell J. S. Orr, Thomas Cavalier-Smith ,Kamran Shalchian-Tabrizi ,Fabien Burki , Asmund Skjæveland and Kjetill S. Jakobsen\

Geomicrobiology, Fifth EditionBy Henry Lutz Ehrlich, Dianne K. Newman

Prehistoric Life: Evolution and the Fossil Record Bruce S. Lieberman (University of Kansas), Roger L. Kaesler (University of Kansas) March 2010, ©2010, Wiley-Blackwell

Appl Environ Microbiol. 2006 October; 72(10): 6638–6643.
doi: 10.1128/AEM.02547-05 Molecular Comparisons of Freshwater and Marine Isolates of the Same Morphospecies of Heterotrophic Flagellates

Frank Scheckenbach,1 Claudia Wylezich,1 Alexander P. Mylnikov,2 Markus Weitere,1 and Hartmut Arndt1,*

Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree Thomas Cavalier-Smith*

Reconstructing a complex early Neoproterozoic eukaryote, Wynniatt Formation, arctic Canada NICHOLAS BUTTERFIELD

Qianqian Zhang, Alastair Simpson and Weibo Song multigene analyses haptorian ciliates (Ciliophora, Litostomatea) based on

Mitochondrial Genome of the Homoscleromorph Oscarella carmela (Porifera, Demospongiae) Reveals Unexpected Complexity in the Common Ancestor of Sponges and Other Animals Xiujuan Wang and Dennis V. Lavrov Department of Ecology, Evolution and Organismal Biology, Iowa State University

Oldest Animal Discovered—Earliest Ancestor of Us All?

The real ‘kingdoms’ of eukaryotes Alastair G.B. Simpson1, , Andrew J. Roger2,

 

updated on 12/15/2012 ©1994-2012 Foster P. Carr MD all rights reserved