The major evolutionary transitions

  title={The major evolutionary transitions},
  author={E{\"o}rs Szathm{\'a}ry and John Maynard Smith},
There is no theoretical reason to expect evolutionary lineages to increase in complexity with time, and no empirical evidence that they do so. Nevertheless, eukaryotic cells are more complex than prokaryotic ones, animals and plants are more complex than protists, and so on. This increase in complexity may have been achieved as a result of a series of major evolutionary transitions. These involved changes in the way information is stored and transmitted. 

The Major Transitions in Early Evolution

Features of autonomy and robustness in early evolution are brought into focus in this chapter, showing that metazoan autonomy evolved in successive steps.


  • D. McShea
  • Biology
    Evolution; international journal of organic evolution
  • 1996
A scheme for understanding complexity is proposed that provides a conceptual basis for objective measurement and shows complexity to be a broad term covering four independent types.

The evolution of multicellularity and early animal genomes.

It Takes Two to Evolve Too. The Hypothesis on Three Primary Communication Transitions in Evolution

The “symbiogenetic” framework of interaction of two partners is proposed, outlining similar steps essential for three major advents: the origin of life, theorigin of complex life and the originof humans.

A Virtue Made of Necessity: Is the Increasing Hierarchical Complexity of Sexual Clades an Inevitable Outcome of Their Declining (Macro)evolutionary Potential?

The model explains all components of McShea’s “Evolutionary Syndrome,” i.e. the trend of increasing the hierarchical complexity of organisms, the growth of variability among elements on the immediately lower level, and their gradual machinification.

Evolution of primate gene expression

A neutral model where negative selection and divergence time are the major factors is a useful null hypothesis for both transcriptome and genome evolution.

Prokaryote and eukaryote evolvability.

Major transitions in evolution by genome fusions: from prokaryotes to eukaryotes, metazoans, bilaterians and vertebrates

  • J. Spring
  • Biology
    Journal of Structural and Functional Genomics
  • 2004
The major transitions in human evolution from prokaryotes toeukaryotes, from protozoans to metazoans, from the first animals tobilaterians and finally from a primitive chordate to vertebrates wereall

Conflict and cooperation in eukaryogenesis: implications for the timing of endosymbiosis and the evolution of sex

It is argued that sex represents a rather late proto-eukaryotic innovation, allowing for the growth of the chimeric nucleus and contributing to the successful completion of the evolutionary transition.



The integration of the earliest genetic information.

The evolution of chromosomes. II. Molecular mechanisms.

Molecular mechanisms whereby separate RNA genes could have become linked to form chromosomes, monocistronic transcripts could have been made from these chromosomes, and RNA was replaced by DNA as the genetic material are suggested.

RNA evolution and the origins of life

It is doubtful that life began with RNA, but consideration of what came before RNA must take into account relevant information from geochemistry, prebiotic chemistry and nucleic acid biochemistry.

The evolutionary dynamics of repetitive DNA in eukaryotes

Features of the organization of repetitive sequences in eukaryotic genomes, and their distribution in natural populations, reflect the evolutionary forces acting on selfish DNA.

The Major Transitions in Evolution

This book discusses the origins of societies, development and evolution, and the development of spatial patterns in simple organisms.

Phylogeny from function: evidence from the molecular fossil record that tRNA originated in replication, not translation.

  • N. MaizelsA. Weiner
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1994
This phylogeny is unique in suggesting that the function of tRNA in replication dates back to the very beginnings of life on earth, before the advent of templated protein synthesis.

The Origin of Eukaryote and Archaebacterial Cells

It is argued that the most primitive eukaryote was a phagotrophic archezoan, with no chloroplasts, no mitochondria, no microbodies, and no stacked smooth cisternae forming a Golgi dictyosome, but possessing a single cilium with a sheaf of rootlet microtubules surrounding the single nucleus that divided by a closed mitosis.

The evolution of the development

The evolution of development required few new features not already present in the eukaryotic cell, as exemplified by the cell cycle. Moreover, the protozoa possess many features of spatial

The case for an ancestral genetic system involving simple analogues of the nucleotides.

It is proposed that RNA was preceded in the evolution of life by a polymer constructed from flexible, acyclic, probably prochiral nucleotide analogues that were synthesized readily on the primitive earth.