Nucleotide Substitutions during Speciation may Explain Substitution Rate Variation

Abstract Although molecular mechanisms associated with the generation of mutations are highly conserved across taxa, there is widespread variation in mutation rates between evolutionary lineages. When phylogenies are reconstructed based on nucleotide sequences, such variation is typically accounted...

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Bibliographic Details
Published in:Systematic biology 2022-08, Vol.71 (5), p.1244-1254
Main Authors: Janzen, Thijs, Bokma, Folmer, Etienne, Rampal S
Format: Article
Language:English
Subjects:
Biological Evolution
Evolution, Molecular
Models, Genetic
Mutation
Nucleotides
Phylogeny
Points of View
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Summary:Abstract Although molecular mechanisms associated with the generation of mutations are highly conserved across taxa, there is widespread variation in mutation rates between evolutionary lineages. When phylogenies are reconstructed based on nucleotide sequences, such variation is typically accounted for by the assumption of a relaxed molecular clock, which is a statistical distribution of mutation rates without much underlying biological mechanism. Here, we propose that variation in accumulated mutations may be partly explained by an elevated mutation rate during speciation. Using simulations, we show how shifting mutations from branches to speciation events impacts inference of branching times in phylogenetic reconstruction. Furthermore, the resulting nucleotide alignments are better described by a relaxed than by a strict molecular clock. Thus, elevated mutation rates during speciation potentially explain part of the variation in substitution rates that is observed across the tree of life. [Molecular clock; phylogenetic reconstruction; speciation; substitution rate variation.]
ISSN:1063-5157
1076-836X
1076-836X
DOI:10.1093/sysbio/syab085