The present invention relates to novel methods for generating variant proteins with increased host string content by comparing a parent protein sequence with two or more natural protein sequences from a host species, analyzing one or more amino acid strings of the parent protein sequence with a structurally corresponding amino acid string of each of said natural protein sequences, substituting one or more amino acid strings of the parent protein sequence with a structurally corresponding amino acid string of one of the two or more natural protein sequences on an amino acid string by amino acid string basis so that the variant protein has increased host string content, and, synthesizing and screening the variant protein.