Gene conversion diversifies chicken Ig genes. Gene conversion at the chicken Igλ locus. The rearranged λ gene variable (VJ) and constant (C) region is transcribed to encode the Igλ light chain polypeptide (at right); upstream pseudo-V (ψV) donors are templates for sequence transfer (above). Tracts of templated mutation are evident in the diversified V region and the encoded protein (below). Gene conversion proceeds by a pathway in which the target V region is cleaved and then undergoes homology-directed repair templated by the ψV regions (boxed inset).