Fig. 2. The Lfng^FCE1 allele interferes with normal skeletal development during primary body formation. (A) Representative phenotypes of Lfng^+/-, Lfng^FCE1/FCE1 and Lfng^-/- mice. The Lfng^FCE1/FCE1 mouse has a shortened body and kinked tail. (B) Skeletal preparations of wild-type (a,b,g), Lfng^FCE1/FCE1 (c,d,h) and Lfng^-/- (e,f,i) mice. Ventral (a,c,e) and dorsal (b,d,f) views of the ribs and dorsal views of the lumbar and sacral spine (g-i) are shown. The thoracic regions of Lfng^FCE1/FCE1 (c,d) and Lfng^-/- (e,f) mice exhibit rib fusions (arrows) and disorganized vertebrae. In Lfng^FCE1/FCE1 skeletons, vertebral disorganization extends through the lumbar region (bar, h), but normal vertebral condensations are seen in the sacral spine (^*). By contrast, vertebral disorganization extends throughout the lumbar (bar) and sacral (^*) regions of Lfng^-/- skeletons (i), and the tail appears severely truncated. (C) Rib abnormalities were quantified in Lfng wild-type (n=17), Lfng^FCE1/FCE1 (n=11) and Lfng^-/- (n=8) neonates. Results are shown as bar and whisker graphs (solid horizontal line indicates the mean), with the number of rib abnormalities indicated on the y-axis. The number of rib abnormalities is similar in Lfng^-/- and Lfng^FCE1/FCE1 animals (P=0.236, the null hypothesis is accepted). (D) Tail anomalies were quantified in adult animals. The proportion of animals with 0-1 kinks, 2-5 kinks or truncated tails are shown. Forty percent of Lfng^FCE1/FCE1 animals exhibit mild tail defects (0-1 kinks), while the remaining animals had between 2 and 5 kinks. By contrast, Lfng^-/- animals exhibit truncation in the tail region.