'PCR-tractable' originates from a combination of the initialism 'PCR' (from 'polymerase chain reaction', a modern scientific term coined in the 1980s) and the English adjective 'tractable', where the root 'tract-' derives from Latin 'tractare' meaning 'to handle or manage'.

'tractable' changed from Latin 'tractare' into Old French and Middle English forms and eventually became the modern English adjective 'tractable'; the element 'PCR' is a modern acronym for the laboratory technique and was appended to form the compound adjective 'PCR-tractable'.

Initially 'tractable' meant 'able to be handled or managed'; over time it retained the core sense of 'manageable' and in scientific compounds like 'PCR-tractable' the sense specialized to 'amenable to handling by PCR methods'.