Fix handling of empty fields
Fix handling of empty fields

HazyResearch/dd-genomics,HazyResearch/dd-genomics,HazyResearch/dd-genomics,amwenger/dd-genomics,amwenger/dd-genomics,rionda/dd-genomics,HazyResearch/dd-genomics,HazyResearch/dd-genomics,rionda/dd-genomics,amwenger/dd-genomics