Fig. 6

leo gap junctions are required in melanophores and xanthophores but not in iridophores.

Typical examples of chimeric animals derived from blastomere transplantations are shown. Cells from leo^tK3;nac;pfe donor embryos, which can provide iridophores as their only chromatophore type, were transplanted in rse hosts, which lack most iridophores. The resulting chimeric animals (17 clones in 34 fish) show that mutant iridophores form a wild-type pattern when confronted with wild-type xanthophores and melanophores (A and A'). When cells are transplanted from leo^tK3;spa;rse donors into pfe hosts, thereby creating chimeras with mutant xanthophores (present in the anterior part of the fish, left to the dotted line in B') and wild-type iridophores and melanophores, there is no wild-type pattern formed, but the chromatophores are almost uniformly distributed (B and B′) (9 clones in 72 fish). When cells are transplanted from leo^tK3;pfe;rse donors into nac hosts, thereby creating chimeras with mutant melanophores and wild-type iridophores and xanthophores (3 clones in 68 fish), again, no wild-type pattern is formed, but the mutant melanophores form loosely arranged fields of cells (C and C').