nonhuman gene deletion 78 article 70 priority journal 66 controlled study 62 metabolism 34 Animals 30 unclassified drug 30 Gene Deletion 28 animal cell 26 Mice 22 enzyme activity 22 genetics 22 mouse 22 phenotype 22 Repressor Proteins 20 animal experiment 20 animal tissue 20 gene mutation 20 Article 18 Bacterial Proteins 18 Humans 18 Mice, Transgenic 18 bacterial strain 18 gene expression regulation 18 human 18 physiology 18 promoter region 18 protein expression 18 Mutation 16