Rock stone 81
Felsenstein 81 (F81) is a method developed by the American scientist Joseph Felsenstein in 1981 to correct distance data from sequence alignments .
In order to construct a family tree, orthologous sequences of genome sections , mostly genes, are written among each other and "sensibly" compared with each other (creation of a multiple sequence alignment ). Family trees can then be created from this. There are two basic ways to do this. Either each individual character ( amino acid in protein sequences or bases in DNA ) ( character-oriented family tree creation ) is compared, or the individual positions are converted into so-called distance data. The distances between the characters are calculated and a matrix is created from this, with which the sequences can be compared ( matrix-oriented family tree creation ).
Since there are also reverse mutations over time , the raw distance values must be corrected.
In contrast to Jukes & Cantor or Kimura-2 parameters, F81 assumes that the nucleotide composition is different. In F81, as in Jukes & Cantor, it is assumed that the conversion of the bases or amino acids into one another takes place with the same probability.
Individual evidence
- ↑ Volker Knoop, Kai Müller: Genes and family trees: A handbook on molecular phylogenetics . Springer-Verlag, 2009, ISBN 978-3-8274-2230-9 ( google.de [accessed February 1, 2019]).