Related Experiment Video
Updated: Jul 3, 2026
12:00
A Practical Guide to Phylogenetics for Nonexperts
Published on: February 5, 2014
A likelihood framework for estimating phylogeographic history on a continuous landscape.
Alan R Lemmon1, Emily Moriarty Lemmon
1Section of Integrative Biology, University of Texas-Austin, Austin, Texas 78712, USA. alemmon@evotutor.org
Systematic Biology
|August 8, 2008
Summary
Biologists can now estimate phylogeographic history and test hypotheses without prior assumptions using a new statistical framework. This approach aids in understanding gene history and ancestral geographic locations for species like North American chorus frogs.
Area of Science:
- Evolutionary Biology
- Genetics
- Ecology
Background:
- Traditional phylogeographic methods lack adequate statistical frameworks for hypothesis testing.
- New methods often prioritize hypothesis testing over descriptive utility.
- Biologists need tools for both hypothesis testing and descriptive estimation of phylogeographic history.
Purpose of the Study:
- To develop a novel statistical framework for phylogeographic analysis.
- To enable testing of a priori hypotheses and estimation of gene history without prior assumptions.
- To estimate ancestral geographic locations and associated statistical confidence.
Main Methods:
- Developed a statistical framework focusing on ancestral geographic location estimation.
- Utilized a maximum likelihood approach to derive ancestral coordinates and dispersal parameters.
- Implemented the framework in a new program called PhyloMapper.
- Applied the method to a 246-taxon mitochondrial genealogy of North American chorus frogs (Pseudacris feriarum).
Main Results:
- Demonstrated evidence for recent northward expansion in Pseudacris feriarum.
- Identified higher per-generation dispersal, noncentral ancestral location, and directional migration.
- Showcased a method for accommodating phylogenetic uncertainty.
- Illustrated the framework's utility in phylogeographic analyses.
Conclusions:
- The developed framework offers both hypothesis testing and descriptive capabilities for phylogeography.
- The PhyloMapper program provides a robust tool for analyzing gene history and ancestral locations.
- Future extensions can incorporate ecological and geological data for more comprehensive phylogeographic insights.
Related Concept Videos
02:54Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
01:28Microbial Phylogeny
Understanding the evolutionary relationships among microorganisms is fundamental to microbial ecology and taxonomy. Phylogenetic trees are essential tools for inferring these relationships, relying primarily on comparative analyses of molecular sequences such as DNA, RNA, or proteins. In microbial studies, these trees typically depict the evolutionary paths of diverse bacterial and archaeal species by mapping genetic differences accumulated over time.Phylogenetic trees are composed of tips,...
02:16Genetics of Speciation
Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.The genetics of speciation involves the different traits or isolating mechanisms preventing gene exchange, leading to reproductive isolation. Reproductive isolation can be due to reproductive barriers that have effects either before or after the formation of a zygote. Pre-zygotic mechanisms prevent fertilization from occurring, and post-zygotic mechanisms...
01:23Phylogeny
Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon (singular). Taxa (plural) can span different levels of the evolutionary hierarchy. For instance, the group containing all birds is a taxon (comprising the class Aves), and the group of all species of daisies (the genus Bellis) is a taxon. Phylogenies can likewise include just one genus (i.e., depict species relationships) or span an entire...
01:07Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
03:21Phylogenetic Trees
Phylogenetic trees come in many forms. It matters in which sequence the organisms are arranged from the bottom to the top of the tree, but the branches can rotate at their nodes without altering the information. The lines connecting individual nodes can be straight, angled, or even curved.The length of the branches can depict time or the relative amount of change among organisms. For instance, the branch length might indicate the number of amino acid changes in the sequence that underlies the...