Detection of chimerism.

(A) PCR analysis of tail DNA. To detect the contribution of Shp-2^−/− ES cells to the body of chimeric animals, tail DNA was extracted from Shp-2^−/−/Rag-2^−/−chimeras as well as one Rag-2^−/− animal as a control. Detection of wild-type (wt) and mutant (mt) Shp-2 alleles was done by PCR analysis. (B) Southern blot analysis of DNA extracted from bone marrow, thymus, and spleen of Shp-2^+/−/Rag-2^−/− or Shp-2^−/−/Rag-2^−/− chimeras. Wild-type and mutant Shp-2 alleles were detected using a specific probe as described previously.8 (C) One Rag-2^−/− animal (left) and 3 Shp-2^−/−/Rag-2^−/− chimeric mice with kinky tail are shown.