Título del libro: The Molecular Evolutionary Clock: Theory And Practice
Título del capítulo: Principles of molecular dating
SUSANA AURORA MAGALLON PUEBLA;
Autores externos:
Idioma:
Año de publicación:
2021
Palabras clave:
Branch lengths; Calibrations; Fossilized birth-death process; Fossils; Molecular clock; Node-dating; Nonparametric rate smoothing; Penalized likelihood; Tip-dating
Resumen:
Time-calibrated trees are a fundamental starting point for investigating organismal evolution. The use of molecular sequence data to infer the time of lineage origin and diversification was initially based on the assumption that molecular rates were homogeneous across lineages, giving rise to the original concept of the molecular clock. Evidence of vast rate heterogeneity, even among closely related species, prompted the development of clock models that account for among-lineage rate heterogeneity. In particular, relaxed clocks allow each branch in the phylogenetic tree to have a unique rate. Relaxed clocks include numerical, semiparametric, and parametric methods, the last of these in fully Bayesian implementations. Absolute temporal information is typically used to separate the time and rate components of the branches in a phylogenetic tree. Temporal information can be obtained from fossils, which provide minimum calibration ages; from extrinsic events linked to cladogenesis, which can provide maximum calibration ages; or from age intervals estimated in independent analyses. Importantly, molecular clocks differ in terms of how temporal information is introduced. In node-dating methods, temporal information is used to calibrate internal phylogenetic nodes, and the resulting time-trees typically include only extant taxa. In tip-dating methods, temporal information is provided by fossils that are included in the data matrix. In the resulting time-tree, fossils appear as tips of extinct branches. In the fossilized birth-death process, temporal information is provided by fossils which, together with molecular data from extant species, influence the diversification process that generates the tree prior. In the resulting time-tree, fossils are extinct tips or sampled ancestors of lineages. © Springer Nature Switzerland AG 2020. All rights reserved.
Entidades citadas de la UNAM:
ISBN:
9783030601812
Editorial:
Springer International Publishing Nombre de la publicación:
Principles of molecular dating
Página inicial:
67
Página final:
81
