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Encyclopedia > Long branch attraction

Long branch attraction (LBA) is a phenomenon in phylogenetic analyses (most commonly those employing maximum parsimony) when rapidly evolving lineages are inferred to be closely related, regardless of their true evolutionary relationships. The problem arises when the DNA of two (or more) lineages evolves rapidly. There are only four possible nucleotides and when DNA substitution rates are high, the probability that two lineages will independently evolve the same nucleotide at the same site increases. When this happens, parsimony erroneously interprets this similarity as a synapomorphy (i.e., evolving once in the common ancestor of the two lineages). A phylogeny (or phylogenesis) is the origin and evolution of a set of organisms, usually of a species. ... Maximum parsimony is a simple but popular technique used in cladistics to predict an accurate phylogenetic tree for a set of taxa (commonly a set of species or reproductively-isolated populations of a single species). ... A speculatively rooted phylogenetic tree of all living things, based on rRNA gene data, showing the separation of the three domains, bacteria, archaea, and eukaryotes, as described initially by Carl Woese. ... Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and most viruses). ... A nucleotide is an organic molecule consisting of a heterocyclic nucleobase (a purine or a pyrimidine), a pentose sugar (deoxyribose in DNA or ribose in RNA), and a phosphate or polyphosphate group. ... In biology, mutations are changes to the genetic material (usually DNA or RNA). ... Shared characteristics that define a cladistic grouping. ...


This problem can be minimized by using methods that incorporate differential rates of substitution among lineages (e.g., maximum likelihood).


References

  • Felsenstein, J. 2004. Inferring Phylogenies. Sinauer Associates, Sunderland, MA.

 
 

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