diff --git a/lisa/lisa_user_data/coverage_test.py b/lisa/lisa_user_data/coverage_test.py
index 1d44fe3..ce45b52 100644
--- a/lisa/lisa_user_data/coverage_test.py
+++ b/lisa/lisa_user_data/coverage_test.py
@@ -119,6 +119,10 @@ def convert_bigwig(cls, bigwig, species, log = None):
                 if window.chromosome in coverage_bw.chroms():
                     mean_coverage = coverage_bw.stats(*window.to_tuple())[0]
                     coverage_array[i] = mean_coverage
+                # sometimes, in the bigwig files, genome chromosome names do not start with 'chr'
+                elif window.chromosome[3:] in coverage_bw.chroms():
+                    mean_coverage = coverage_bw.stats(window.chromosome[3:],window.start,window.end)[0]
+                    coverage_array[i] = mean_coverage
 
                 if i%1000 == 0:
                     log.append(bar, update_line = True)
@@ -203,4 +207,4 @@ def predict(self, query_list, background_list = [], background_strategy = 'all',
                 Test metadata. Includes query genes provided and background genes that were selected, as well as reg-scores for top 100 factors on selected genes.
         '''
         return super().predict(query_list, region_scores = self.coverage_array, background_list=background_list, background_strategy=background_strategy, 
-            num_background_genes= num_background_genes, seed=seed)
\ No newline at end of file
+            num_background_genes= num_background_genes, seed=seed)