DIZYGOTIC MOSAIC ANIMALS (CHIMERAS, ALLOPHENICS) ARE EXPERIMENTALLY PRODUCED BY AMALGAMATING PREIMPLANTATION EMBRYONIC TISSUES.

DIZYGOTIC MOSAIC ANIMALS (CHIMERAS, ALLOPHENICS) ARE EXPERIMENTALLY PRODUCED BY AMALGAMATING PREIMPLANTATION EMBRYONIC TISSUES. THE COMBINED EMBRYOS ARE REMOVED TO THE REPRODUCTIVE TRACT OF PSEUDOPREGNANT SURROGATE MOTHERS. ADULT TISSUES OF THE OFFSPRING ARE MOSAIC OF THE PROGENY OF CELLS DERIVED FROM ONE OR THE OTHER OF THE GENOTYPES ORIGINALLY MIXED. IF THE CELL TYPES ARE DISTINGUISHABLE IN SOME WAY, THEN THE MOSAICISM CAN BE DEMONSTRATED. MOST OF THE DEVELOPMENTAL STUDIES UTILIZING CHIMERIC ANIMALS ARE CHARACTERIZED BY BIOCHEMICAL MARKERS FOR WHICH TISSUES ARE HOMOGENIZED AND THEN ANALYZED BY ELECTROPHORESIS. THE IDEALMARKER OF CHIMERISM WOULD BE CILL AUTONOMOUS, UBIQUITOUSLY EXPRESSED, AND USEFUL IN HISTOLOGIC SECTION. BIOQUAL HAS RECENTLY DEVELOPED SUCH A SYSTEM FOR THE RAT. EMBRYOS OF CONGENIC STRAINS OF RAT VARYING IN EXPRESSION OF CLASS I MAJOR HISTOCOMPATIBILITY ANTIGENS ARE COMBINED BY AGGREGA- TION. THE RESULTING CHIMERIC TISSUES ARE DISTINGUISHABLE INHISTOLOGICAL SECTION WITH IODINATED MONOCLONAL ANTIBODIES DIRECTED TO THE VARIANT MAJOR HISTOCOMPATIBILITY ANTIGENS. THE WIDESPREAD USEFULNESS OF SUCH A SYSTEM IN DEVELOPMENTAL APPEARS CERTAIN. BIOQUAL PROPOSES TO PRODUCE THIS INNOVATIVE RESEARCH TOOL; CUSTOM-DEVELOPED STANDARDIZED CHIMERIC RATS.