Triploid↔diploid chimeras. Histological sections and DNA in situ hybridisation of (A and B) E9.5 2n↔2n control chimera TrC-21, (C and D) E9.5 3n↔2n chimera TrC-16 and (E and F) E9.5 3n↔2n chimera TrB-3. Arrows show (B) examples of 2n (Tg/−) nuclei with single hybridisation signals and (D) examples of 3n (Tg/Tg/−) nuclei with two hybridisation signals. (F) An abnormal allantoic vesicle in E9.5 3n↔2n chimera TrB-3 (ch, chorion; al, allantoic vesicle; vys, visceral yolk sac). Scale bars=200 μm (A, C, E and F) and 20 μm (B and D).