Overview of the skeletal phenotypes in <i>Btg1-</i> and <i>Btg2</i>-deficient mice.

<p>Axial vertebrae are indicated by different colors: green (cervical), yellow (thoracic), blue (lumbar) and red (sacral). The thoracic ribs are indicated by the grey horizontal lines, of which T1-T7 form sternocostal junctions with the sternum. <i>Btg1-</i> and <i>Btg2-</i>deficient mice display C7 to T1 posterior transformation, while <i>Btg1</i>^-/- mice show also partial or complete L6 to S1. <i>Btg2^-/-</i> mice display in most cases T13 to L1 and complete L6 to S1 transformations. <i>Btg1^-/-</i>,<i>Btg2^-/-</i> double knockout animals display a more pronounced phenotype with C7 to T1, T13 to L1 and L6 to S1 homeotic transformations.