diff --git a/DESCRIPTION b/DESCRIPTION
index 61d620a..a76943a 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -2,7 +2,7 @@ Type: Package
 Package: MotrpacRatTraining6mo
 Title: Analysis of the MoTrPAC endurance exercise training data in
     6-month-old rats
-Version: 1.6.5
+Version: 1.6.6
 Authors@R: c(
     person("Nicole", "Gay", , "nicole.r.gay@gmail.com", role = c("cre", "aut")),
     person("David", "Amar", , "ddam.am@gmail.com", role = "aut"),
@@ -29,7 +29,7 @@ Imports:
     dplyr,
     edgeR,
     ggplot2,
-    ggraph,
+    ggraph (>= 2.2.0),
     grid,
     igraph,
     limma,
diff --git a/NEWS.md b/NEWS.md
index 5b83a45..cc62b97 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# MotrpacRatTraining6mo 1.6.6 (2024-06-14)
+
+* Fix bug due to backwards incompatibility between `ggraph` 2.1.0 and 2.2.0. Require `ggraph >= 2.2.0`.
+
 # MotrpacRatTraining6mo 1.6.5 (2023-11-08)
 
 * Point to development version of `RCy3` from GitHub to avoid `R-CMD check` error `RCy3: Can't install dependency uchardet`. 
diff --git a/R/bayesian_graphical_clustering.R b/R/bayesian_graphical_clustering.R
index af2285a..e91285f 100644
--- a/R/bayesian_graphical_clustering.R
+++ b/R/bayesian_graphical_clustering.R
@@ -922,7 +922,7 @@ get_tree_plot_for_tissue <- function(
     d_g_our_layout[grepl(n,d_g_our_layout$name),"y"] = l_y_lim[1] + (j-1)*yjump
   }
   # make sure that the 0w node is in the same line as of the no response
-  d_g_our_layout[d_g_our_layout$name == "0w","y"] = d_g_our_layout[grepl("F0_M0",d_g_our_layout$name),"y"][1]
+  d_g_our_layout[d_g_our_layout$name == "0w","y"] = d_g_our_layout[grepl("F0_M0",d_g_our_layout$name),"y"][1,1]
   # set node sizes and other features
   igraph::V(d_g)$setsize = d_nodes[V(d_g)$name,"size"]
   igraph::V(d_g)$setsize[V(d_g)$name == "0w"] = stats::median(igraph::V(d_g)$setsize)