What does sui generis mean?
Sui generis
Sui generis (/ˌsuːiˈdʒɛnərɪs/;[1] Latin:[ˈsʊ.iː ˈɡɛnɛrɪs]) is a Latin phrase that means "of its (his, her, their) own kind; in a class by itself; unique."[2]
True-breeding organism
A true-breeding organism, sometimes also called a purebred, is an organism that always passes down certain phenotypic traits (i.e. physically expressed traits) to its offspring of many generations. An organism is referred to as true breeding for each trait to which this applies, and the term "true-breeding" is also used to describe individual genetic traits.