diff --git a/src/util/entropyCreateStateFromJsons.ts b/src/util/entropyCreateStateFromJsons.ts
index 625d2e95a..9beeab14e 100644
--- a/src/util/entropyCreateStateFromJsons.ts
+++ b/src/util/entropyCreateStateFromJsons.ts
@@ -130,8 +130,7 @@ export const genomeMap = (annotations: JsonAnnotations): Chromosome[] => {
     .map(([annotationKey, annotation]) => {
       const geneName = annotation.gene || annotationKey;
       if (!(geneName in annotationsPerGene)) annotationsPerGene[geneName] = {};
-      const gene = annotationsPerGene[geneName];
-      gene[annotationKey] = annotation;
+      annotationsPerGene[geneName][annotationKey] = annotation;
     })
 
   const nextColor = nextColorGenerator();