add some more indexes
{"collection": "regulatory_region", "fields": {"featureType": 1}, "options": {"background": true}}
{"collection": "repeats", "fields": {"_chunkIds": 1, "start": 1, "end": 1}, "options": {"background": true}}
+{"collection": "repeats", "fields": {"chromosome": 1, "start": 1, "end": 1}, "options": {"background": true}}
+{"collection": "repeats", "fields": {"_chunkIds": 1}, "options": {"background": true}}
{"collection": "variation", "fields": {"_chunkIds": 1}, "options": {"background": true}}
{"collection": "variation", "fields": {"chromosome": 1, "start": 1, "end":1}, "options": {"background": true}}
