What is the % identity to C7orf38 of the animal whose common name is rat?
CREATE TABLE "orthologs" (
  "common_name" text,
  "genus_species" text,
  "ncbi_accession_number" text,
  "length_aa" real,
  "pct_identity_to_c7orf38" real,
  "pct_similarity_to_c7orf38" real
);
SELECT MIN("pct_identity_to_c7orf38") FROM "orthologs" WHERE "common_name"='Rat';