Cell
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Thymocytes from mice congenitally deficient for TCR alpha chain synthesis were examined for the status of their TCR beta chain genes, by DNA sequencing and by a novel technique that analyzes populations of gene rearrangements. TCR beta chain genes were predominantly productively rearranged, in contrast with the statistical prediction for a quasi-random rearrangement process. ⋯ Moreover, the beta chain gene rearrangements in TCR alpha-/-mice are typical of those found in the thymus and periphery of normal mice. Thus, the extent of junctional diversity is a property of TCR genes that is imposed prior to selection on the mature alpha beta TCR.