Preaxial polydactyly and blood-filled blisters in the hindlimbs of <i>Fras1^bfb/bfb</i> mice.

<p>Blood-filled blisters are evident in the hindlimbs of <i>Fras1^bfb/bfb</i> at E14.5 (A and B) and E17.5 (C and D), often distorting the digits. A proportion of <i>Fras1^bfb/bfb</i> exhibit preaxial polydactyly (asterisks in E-H), evident in E14.5 and E17.5 wholemounts (E and F), E17.5 skeletal preparations (G) and E12.5 Sox9 in situ stained embryos (H). Evidence of a blister can also be seen in an E17.5 skeletal preparation (arrowhead in G). Digit numbers are indicated in (G).