diff --git a/src/matrix/dataset_util.js b/src/matrix/dataset_util.js
index 66655680c2f0a45ce0533caaa8d4fc8330a1f96e..75e82c44c32ea3d5c5288f97ff084cba70d9b235 100644
--- a/src/matrix/dataset_util.js
+++ b/src/matrix/dataset_util.js
@@ -53,8 +53,10 @@ morpheus.DatasetUtil.getDatasetReader = function(ext, options) {
 		if (options && options.regions) {
 			datasetReader.setRegions(options.regions);
 		}
-	} else {
+	} else if (ext === 'txt' || ext === 'tsv' || ext === 'csv') {
 		datasetReader = new morpheus.TxtReader();
+	} else {
+		datasetReader = new morpheus.GctReader();
 	}
 	return datasetReader;
 };
@@ -435,7 +437,6 @@ morpheus.DatasetUtil.getSeriesNames = function(dataset) {
 	return names;
 };
 
-
 /**
  * Search dataset values.
  */