<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>The reciprocal product of T-cell receptor (TCR) gene rearrangement. Following TCR gene rearrangement the T-cell receptor excision circle (TREC) is maintained in the cell as a non-replicating episome. With each cell division the TREC is segregated to a single daughter cell and becomes diluted in the population. Recent TCR rearrangement can be detected by a spike in the number of TREC and can be used to quantify thymic T-cell output.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>