diff --git a/sequence_extractor/exon_concatenation.py b/sequence_extractor/exon_concatenation.py
index 5bfd28dd5cd1bb21927eb353939a4d1e18ee6d46..909a741ca2f84e4abd581c965f43bae21904c14f 100644
--- a/sequence_extractor/exon_concatenation.py
+++ b/sequence_extractor/exon_concatenation.py
@@ -14,16 +14,16 @@ def exon_concatenation(
 	to_write_to_file = []
 	for x in range(int(len(lines)/2)):
 		if x == 0:
-			annotation = lines[0]
-			read = lines[1]
+			annotation = lines[0][0:16]
+			read = lines[1][:-1]
 		if x >= 1:
-			if lines[2*x] == lines[2*(x-1)]:
-				read+= lines[(2*x)+1]
+			if lines[2*x][1:16] == lines[2*(x-1)][1:16]:
+				read+= lines[(2*x)+1][:-1]
 			else:
 				to_write_to_file.append(annotation)
 				to_write_to_file.append(read)
-				annotation = lines[2*x]
-				read = lines[(2*x)+1]
+				annotation = lines[2*x][0:16]
+				read = lines[(2*x)+1][:-1]
 	to_write_to_file.append(annotation)
 	to_write_to_file.append(read)
-	return to_write_to_file
\ No newline at end of file
+	return to_write_to_file