constructive neutral evolution
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Complex cellular machines and processes are commonly believed to be products of selection, and it is typically understood to be the job of evolutionary biologists to show how selective advantage can account for each step in their origin and subsequent growth in complexity. Here, we describe how complex machines might instead evolve in the absence of positive selection through a process of "presuppression," first termed constructive neutral evolution (CNE) more than a decade ago. If an autonomously functioning cellular component acquires mutations that make it dependent for function on another, pre-existing component or process, and if there are multiple ways in which such dependence may arise, then dependence inevitably will arise and reversal to independence is unlikely. Thus, CNE is a unidirectional evolutionary ratchet leading to complexity, if complexity is equated with the number of components or steps necessary to carry out a cellular process. CNE can explain "functions" that seem to make little sense in terms of cellular economy, like RNA editing or splicing, but it may also contribute to the complexity of machines with clear benefit to the cell, like the ribosome, and to organismal complexity overall. We suggest that CNE-based evolutionary scenarios are in these and other cases less forced than the selectionist or adaptationist narratives that are generally told.
- MeSH
- biologická evoluce MeSH
- editace RNA MeSH
- fyziologická adaptace MeSH
- genetický drift MeSH
- lidé MeSH
- modely genetické MeSH
- rostliny anatomie a histologie genetika metabolismus MeSH
- sestřih RNA MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Phylum Euglenozoa comprises three groups of eukaryotic microbes (kinetoplastids, diplonemids, and euglenids), the mitochondrial (mt) genomes of which exhibit radically different modes of organization and expression. Gene fragmentation is a striking feature of both euglenid and diplonemid mtDNAs. To rationalize the emergence of these highly divergent mtDNA types and the existence of insertion/deletion RNA editing (in kinetoplastids) and trans-splicing (in diplonemids), we propose that in the mitochondrion of the common evolutionary ancestor of Euglenozoa, small expressed gene fragments promoted a rampant neutral evolutionary pathway. Interactions between small antisense transcripts of these gene fragments and full-length transcripts, assisted by RNA-processing enzymes, permitted the emergence of RNA editing and/or trans-splicing activities, allowing the system to tolerate indel mutations and further gene fragmentation, respectively, and leading to accumulation of additional mutations. In this way, dramatically different mitochondrial genome structures and RNA-processing machineries were able to evolve. The paradigm of constructive neutral evolution acting on the widely different mitochondrial genetic systems in Euglenozoa posits the accretion of initially neutral molecular interactions by genetic drift, leading inevitably to the observed 'irremediable complexity'.
... and Screening of DNA Libraries 525 Construction of Genomic Libraries 526 Construction of cDNA Libraries ... ... of Green Fluorescent Protein as a Reporter of Protein Synthesis 574 Evolution of Genomes 577 -- Genome ... ... Evolution in the Cereal Grasses 577 Genome Evolution in Mammals 579 Human Genetics Sidelight: The Race ... ... 799 -- Humans and the Great Apes 799 Human Evolution in the Fossil Record 799 DNA Sequence Variation ... ... and Human Origins 800 Technical Sidelight: Molecular Evolution and the Neutral Theory 790 A Conversation ...
2nd ed. xviii, 876 s. : il.
... Organisms Help and Hurt Us 4 -- Viruses Are the Ultimate Parasites 6 -- Changes in Cells Underlie Evolution ... ... Most Successful Biological Studies Use Multiple -- Approaches 27 -- 1.5 -- A Genome Perspective on Evolution ... ... the Genetic Code, and Organelle -- Structures Are Nearly Universal 28 -- Darwin\'s Ideas About the Evolution ... ... Be Screened by Hybridization to an Oligonucleotide Probe 181 -- Yeast Genomic Libraries Can Be Constructed ... ... of Multifaceted Adhesion Molecules -- Enabled the Evolution of Diverse Animal Tissues 807 -- 19.2 -- ...
6th ed. xxxvii, 1150 s. : il., tab. ; 29 cm
- MeSH
- biologie buňky MeSH
- molekulární biologie MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biologie
- cytologie, klinická cytologie
... Gene Duplication Is a Major Force in Evolution 100 ??? ... ... The Rate of Neutral Substitution Can Be Measured from Divergence of Repeated Sequences 107 -- ??? ... ... Pseudogenes Are Dead Ends of Evolution 108 ?? ... ... Promoter Construction Is Flexible but Context Can Be Important 628 -- ŁESm Enhancers Contain Bidirectional ...
xvii, 892 s. : il.
- MeSH
- DNA genetika MeSH
- genetické jevy MeSH
- genom MeSH
- geny fyziologie MeSH
- proteiny genetika MeSH
- RNA genetika MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Obecná genetika. Obecná cytogenetika. Evoluce
- NLK Obory
- genetika, lékařská genetika
