In particular, this invention provides novel methods of populating data structures for use in evolutionary modeling. In particular, this invention provides methods of populating a data structure with a plurality of character strings. The methods involve encoding two or more biological molecules into character strings to provide a collection of two or more different initial character strings; selecting at least two substrings from the pool of character strings; concatenating the substrings to form one or more product strings about the same length as one or more of the initial character strings; adding the product strings to a collection of strings; and optionally repeating this process using one or more of the product strings as an initial string in the collection of initial character strings.