subline
/ˈsʌblʌɪn/noun
A subdivision of a line of ancestry. In later use (Genetics ): a population of cells, organisms, etc., derived from an isogenic cell line or inbred line which is distinguished by having a trait differing in some way from the original line, caused by mutation or inherited from a genetically impure ancestor.
Origin
Mid 19th century; earliest use found in Robert Chambers (1802–1871), publisher and writer. From sub- + line.