Laterality defects in E9.5–E10.5 embryos from crosses between <i>Tbx6^tm2Pa/+</i> and <i>Tbx6^tm1Pa/+</i> heterozygous mice and between <i>Tbx6^tm2Pa/+</i> and <i>Tbx6^rv/+</i> heterozygous mice.

1Two had ventrally looped hearts 2Two had tails twisted 1800 so that the umbilicus looped around the dorsal side of the tail; this appeared to be due to greater flexibility of the tail of mutants because of the lack of somites, rather than to an altered direction of turning 3Five had ventrally looped hearts 4One had a tail twisted 1800 5Wild type includes all morphologically normal littermates, which include +/+ and heterozygous embryo1. 2例个体的心脏呈腹侧环曲状（ventrally looped hearts）。 2. 2例个体的尾巴扭转180°，致使脐环环绕至尾巴的背侧；该现象看似源于突变体尾巴因缺乏体节（somites）而具备更高的柔韧性，而非转向方向发生改变。 3. 5例个体的心脏呈腹侧环曲状。 4. 1例个体的尾巴扭转180°。 5. 野生型（Wild type）包含所有形态正常的同窝幼崽，涵盖纯合野生型（+/+）及杂合胚胎。