. 2017 Mar 14;12(3):e0173399. doi: 10.1371/journal.pone.0173399

Table 1. Summary of embryonic phenotypes in double mutant crosses.

Mks1^krc x Bbs4^-/-
Genotype	Mks1^krc/+; Bbs4^+/-	Mks1^krc/krc	Bbs4^-/-	Mks1^krc/krc; Bbs4^-/-
Embryonic Lethal?	No	Yes. Variable: E13.5-E17.5[39]	No	Yes. E13.5
Neural Patterning	Normal	Slight alterations: dorsal expansion of motor neurons, reduction of Nkx2.2. Varies along A-P axis[39]	Normal	Reduced Nkx2.2, ventral shift of motor neurons.
Limbs	Normal	Pre-axial polydactyly in ~50% on at least 1 limb	Normal	Polydactyly in all embryos, all 4 limbs
Cilia Number	Normal	Reduced by ~60% compared to WT	Normal	Similar to Mks1^krc/krc. Lack of ARL13b and other cilia membrane proteins
Mks^krc x Ift172^avc1
Genotype	Mks1^krc/+; Ift172^avc1/+	Mks1^krc/krc	Ift172^avc1/avc1	Mks1^krc/krc; Ift172^avc1/avc1
Embryonic Lethal?	No	Yes. Variable: E13.5-E17.5[39]	Perinatal lethal	Yes. E10.5
Neural Patterning	Normal	Slight alterations: dorsal expansion of motor neurons, reduction of Nkx2.2. Varies along A-P axis[39]	Normal in brachial spinal cord, in lumbar region, motor neurons expanded dorsally [46]	Loss of ventral cell types, motor neurons strongly reduced
Limbs	Normal	Pre-axial polydactyly in ~50% on at least 1 limb	Fully penetrant forelimb polydactyly[40]	N/A (Embryos die prior to digit formation.)
Cilia Number	Normal	Reduced by ~50–60% compared to WT	Similar to WT	Strongly reduced.
Mks1^krc x Dync2h1^mmi
Genotype	Mks1^krc/+; Dync2h1^mmi/+	Mks1^krc/krc	Dync2h1^mmi/mmi	Mks1^krc/krc; Dync2h1^mmi/mmi
Embryonic Lethal?	No	Yes. Variable: E13.5-E17.5[39]	Yes, E10.5	Yes, E10.5
Neural Patterning	Normal	Slight alterations: dorsal expansion of motor neurons, reduction of Nkx2.2. Varies along A-P axis [39].	Loss of ventral cell types, motor neurons present but reduced.	Loss of ventral cell types, motor neurons strongly reduced.
Cilia Number	Normal	Reduced by ~60% compared to WT	Similar to WT, with structural abnormalities.	Strongly reduced.
Bbs4^-/- x Ift172^avc1
Genotype	Bbs4^+/-; Ift172^avc1/+	Bbs4^-/-	Ift172^avc1/avc1	Bbs4^-/-; Ift172^avc1/avc1
Embryonic Lethal?	No	No	Perinatal lethal	Perinatal lethal
Neural Patterning	Normal	Normal	Normal in brachial spinal cord, in lumbar region, motor neurons expanded dorsally [46]	Similar to Ift172^avc1/avc1 single mutants
Cilia Number	Normal	Normal	Similar to WT	Similar to WT