General Considerations (Distance Data Formats)

For a set of m sequences (or taxa), there are m(m-1)/2 pairwise distances. These distances can be arranged either in the lower-left or in the upper-right triangular matrix. After writing the #mega,!Title,!Description, and !Format commands (some of which are optional), you then need to write all the taxa names (see below). Taxa names are followed by the distance matrix. An example of a matrix is:

#one

#two

#three

#four

#five

1.0 2.0 3.0 4.0

 3.0 2.5 4.6

  1.3 3.6

   4.2

In the above example, pairwise distances are written in the upper triangular matrix (upper-right format). Two alternate distance matrix formats are: