Final answer:
The second stage of TCR gene rearrangement in alpha:beta T cells occurs after the functional preTCR is formed. During this stage, the genes that code for the variable regions of the TCR undergo rearrangement, creating diverse TCRs.
Step-by-step explanation:
The second stage of TCR gene rearrangement in alpha:beta T cells occurs after the functional preTCR is formed. During this stage, the genes that code for the variable regions of the TCR undergo rearrangement.
In the a chain of the TCR, one Va segment and one Ja segment are brought together to code for the variable region. In the ß chain, one VB segment is combined with one DB segment and one Jß segment.
The rearrangement of these gene segments allows for the generation of a diverse range of TCRs, enabling T cells to recognize a wide variety of antigens.