Читать книгу Principles of Microbial Diversity - James W. Brown - Страница 55

Tree construction starts with an alignment. Neighbor joining is a distance matrix method, meaning that the alignment is first reduced to a table of evolutionary distances, a distance matrix. The distance matrix cannot be generated directly from the alignment, however, because actual evolutionary distance cannot be directly measured. Instead, the alignment is reduced to a table of observed (measurable) similarity, the similarity matrix. The distance matrix is calculated from the similarity matrix, and then the tree is generated from the distance matrix.