UPMGA
Tree
—
D
11
—
C
14
9
—
B
12
7
8
—
A
D
C
B
A
OTU
—
D
14
—
B
11.5
8.5
—
A-C
D
B
A-C
OTU
Dist. fr A-C to B = 8 + 9 =
8.5
= (A
to B) + (C to B)
2 2
2 2
2 2
Dist. fr A-C to
D = 12 + 11 = 11.5 = (A to D) +
(C to D)
2 2
Dist. fr A-C-B
to D = 12 + 14 + 11 = 12.33333
3
=
(A
to D) + (B to D) + (C to D)
3
First node unites A & C with branch lengths
of 7/2 = 3.5
Second node unites the A-C clade with B with
branch length of 8.5/2 = 4.25
Third node unites A-C-B with D with branch length of 12.33/2
= 6.17
Internode
distances can be calculated by subtraction
Node
1 to Node 2 = (Node 2 to B) - ("Height" of Node 1)
= 4.25 - 3.5 = 0.75
= 4.25 - 3.5 = 0.75
"Height"
of Node 1 can be taken from EITHER branch length 1-A or
1-C because branch lengths from any node to tip are equal by
definition
Node
2 to Node 3 = (Node 2 to D) - ("Height of Node 2)
= 6.17 - 4.25 = 1.91667
= 6.17 - 4.25 = 1.91667
2
3
4
5
1