Related Experiment Video
Updated: Aug 2, 2026
12:00
A Practical Guide to Phylogenetics for Nonexperts
Published on: February 6, 2014
Combining phylogenetic and hidden Markov models in biosequence analysis
1Center for Biomolecular Science and Engineering, University of California, 1156 High Street, Santa Cruz, CA 95064, USA. acs@soe.ucsc.edu
Summary
New models combine phylogenetic and hidden Markov models (HMMs) to track genome evolution. This study introduces an efficient method for higher-order states in HMMs, improving substitution modeling and predictions.
Area of Science:
- Computational Biology
- Genomics
- Evolutionary Biology
Background:
- Traditional phylogenetic models analyze molecular evolution at individual genomic sites.
- Hidden Markov models (HMMs) allow for site-to-site variation in evolutionary processes.
- Integrating these models enhances realism and predictive power for genomic analyses.
Purpose of the Study:
- To review advancements in combined phylogenetic and HMMs.
- To present extensions to existing combined models.
- To introduce an efficient method for incorporating higher-order states in HMMs.
Main Methods:
- Review of current literature on combined phylogenetic and HMMs.
- Development of a novel method for higher-order state accommodation in HMMs.
- Implementation of context-dependent substitution models considering neighboring bases.
Main Results:
- The proposed method efficiently accommodates higher-order states in HMMs.
- Higher-order states, autocorrelated rates, and multiple functional categories significantly improve model fit.
- Higher-order states demonstrated a particularly pronounced positive effect on model performance.
Conclusions:
- Combined phylogenetic and HMMs offer powerful tools for genomic inference and prediction.
- The developed method for higher-order states enhances context-dependent substitution modeling.
- These integrated models represent a significant step forward in understanding genome evolution.
Related Concept Videos
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...
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...
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...
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...
02:51Multi-species Conserved Sequences
Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was completed, scientists studied the genome of primates, mammals, and other phylogenetically distant living beings. Such large-scale studies have provided new insights into the evolutionary relationship between organisms.
Although the genome of each species varies greatly from each other, a few sequences are highly conserved. Such conserved DNA...
Although the genome of each species varies greatly from each other, a few sequences are highly conserved. Such conserved DNA...
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,...