From c3976d8d647383a1f7bb2fbf34e674dd15485a66 Mon Sep 17 00:00:00 2001
From: Haibao Tang <tanghaibao@gmail.com>
Date: Fri, 6 Dec 2024 17:36:14 -0800
Subject: [PATCH] set initial block color to None

---
 jcvi/graphics/dotplot.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/jcvi/graphics/dotplot.py b/jcvi/graphics/dotplot.py
index 90d6c2d1..59dbbf16 100755
--- a/jcvi/graphics/dotplot.py
+++ b/jcvi/graphics/dotplot.py
@@ -286,7 +286,7 @@ def dotplot(
         logger.debug("Capping values within [%.1f, %.1f]", vmin, vmax)
 
     block_id = 0
-    block_color = "k"
+    block_color = None
     for row in fp:
         atoms = row.split()
         if row[0] == "#":