Final answer:
During T cell development, the rearrangement of the α-chain locus through somatic recombination typically results in the deletion of the δ-chain locus given their location on chromosome 14.
Step-by-step explanation:
The question pertains to the T cell receptor (TCR) gene rearrangement, specifically the relationship between the α chain locus and the δ-chain locus on chromosome 14. In the context of T cell development, the α (alpha) and β (beta) chains are part of the TCR complex, which is vital for antigen recognition. When the α-chain locus rearranges during somatic recombination, it often leads to the deletion of the δ-chain locus because these loci are positioned within the same chromosomal region. The correct completion of the given statement would be "if α-chain locus rearranges by somatic recombination, then delta-chain locus is deleted." This is due to the way the genetic material is organized and rearranged during the development of the TCR in thymocytes.