Figure 2.
The nodeslider/Expand move (top to bottom) prunes off branch
-
on the
species tree 
(including clade
), generates a new age for node
, with 
[Equation (6)], rescales the
node ages inside clade 
by 
, and reattaches branch
-
back to
the species tree at the ancestral branch 
at age
(indicated by the arrow).
Affected nodes in the gene tree (
and
, marked by
) are pruned and regrafted,
with node ages inside the clades scaled by 
. In
the reverse Shrink step (from bottom to top), branch 
-
in
is pruned off and reattached to
a descendent branch (
) of the sibling node
(
), at the new age
, generated from Equation
(7). Numeral labels on the
interior nodes in the gene trees are the population IDs.