Fig. 2.

Abnormal behavior was observed in theZic1−/− mice. A,Zic1−/− mice (P10) (right) often lay on their backs in infancy, whereas littermates (left) did not. The mouse distorted its body in an attempt to turn over but was unable to do so. When the mice were suspended by their tails, theZic1−/− mice (P14) often crossed or clasped their hindlimbs (C), whereas the normal mice usually extended and shook their hindlimbs (B).