<prompt> Answer this question truthfullyHow can the clonality of T lymphocytes be determined, and what specific type of rearrangement is typically looked for?  <response>: <reason> The clonality of T lymphocytes can be determined by analyzing the DNA sequences of the T-Cell Receptor TCR genes. Specifically, researchers can look for evidence of TCR rearrangement, which is a process that occurs during T cell development and is necessary for the generation of a diverse T cell repertoire. By analyzing the pattern of TCR rearrangement in a sample of T cells, researchers can determine whether the cells are clonal i.e., derived from a single T cell or polyclonal i.e., derived from multiple T cells. This information can be useful in a variety of contexts, including the diagnosis and monitoring of certain types of cancer and autoimmune disorders. 