Phenotypes associated with this allele

• Allele Symbol: Hoxb8^tm1Omm
• Allele Name: targeted mutation 1, Olga Medina-Martinez
• Allele ID: MGI:2683089
• Summary: 4 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Hoxb8^tm1Omm/Hoxb8^tm1Omm	involves: 129S7/SvEvBrd	MGI:2683138
hm2	Hoxb8^tm1Omm/Hoxb8^tm1Omm	involves: 129S7/SvEvBrd * C57BL/6	MGI:2683139
ht3	Hoxb8^tm1Omm/Hoxb8^+	involves: 129S7/SvEvBrd	MGI:2683140
ht4	Hoxb8^tm1Omm/Hoxb8^+	involves: 129S7/SvEvBrd * C57BL/6	MGI:2683141

Genotype
MGI:2683138

hm1

• Allelic Composition: Hoxb8^tm1Omm/Hoxb8^tm1Omm
• Genetic Background: involves: 129S7/SvEvBrd

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

skeleton

decreased sternebra number ( J:86684 )

• reduction in the number of sternebrae from 5 to 4

abnormal sternocostal joint morphology ( J:86684 )

• as a result of R1 and R2 fusion, the sternocostal joint of the ribs is abnormal sometimes and produces changes in sternum segmentation

• on rare occasions, the eighth rib forms an ectopic joint with the sternum

abnormal rib morphology ( J:86684 )

• in severe cases, the first rib is reduced or absent

rib fusion ( J:86684 )

• the second rib is misdirected, sometimes producing fusion between the first and the second pair of ribs before attaching to the top of the sternum

• on rare occasions, the third rib is abnormally fused to second (R2) and first (R1) ribs

thoracic vertebral transformation ( J:86684 )

• thoracic homeotic transformations: the first thoracic (T1) vertebra develops into the more anterior cervical vertebra C7, and the second thoracic (T2) vertebra develops into T1

• Background Sensitivity: 92% penetrance on a 129S/SvEv genetic background, a higher percentage than on a mixed 129S7/SvEvBrd and C57BL/6 background

Genotype
MGI:2683139

hm2

• Allelic Composition: Hoxb8^tm1Omm/Hoxb8^tm1Omm
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6

mortality/aging

premature death ( J:86684 )

• approximately 2% of homozygotes die after weaning probably due to excessive tooth growth

skeleton

abnormal tooth morphology ( J:86684 )

• excessive tooth growth in mice that die after weaning

decreased sternebra number ( J:86684 )

• reduction in the number of sternebrae from 5 to 4

abnormal sternocostal joint morphology ( J:86684 )

• on rare occasions, the eighth rib forms an ectopic joint with the sternum

• as a result of R1 and R2 fusion, the sternocostal joint of the ribs is abnormal sometimes and produces changes in sternum segmentation

abnormal rib morphology ( J:86684 )

• in severe cases, the first rib is reduced or absent

rib fusion ( J:86684 )

• the second rib is misdirected, sometimes producing fusion between the first and the second pair of ribs before attaching to the top of the sternum

• on rare occasions, the third rib is abnormally fused to second (R2) and first (R1) ribs

thoracic vertebral transformation ( J:86684 )

• thoracic homeotic transformations: the first thoracic (T1) vertebra develops into the more anterior cervical vertebra C7, and the second thoracic (T2) vertebra develops into T1

• Background Sensitivity: 47% penetrance on a mixed genetic background involving 129S/SvEv and C57BL/6, a lower percentage than on a 129S7/SvEvBrd background

craniofacial

abnormal tooth morphology ( J:86684 )

• excessive tooth growth in mice that die after weaning

growth/size/body

abnormal tooth morphology ( J:86684 )

• excessive tooth growth in mice that die after weaning

Genotype
MGI:2683140

ht3

• Allelic Composition: Hoxb8^tm1Omm/Hoxb8⁺
• Genetic Background: involves: 129S7/SvEvBrd

skeleton

thoracic vertebral transformation ( J:86684 )

• thoracic homeotic transformations: the first thoracic (T1) vertebra develops into the more anterior cervical vertebra C7, and the second thoracic (T2) vertebra develops into T1

• Background Sensitivity: 44% penetrance on a 129S/SvEv genetic background, a higher percentage than on a mixed 129S7/SvEvBrd and C57BL/6 background

Genotype
MGI:2683141

ht4

• Allelic Composition: Hoxb8^tm1Omm/Hoxb8⁺
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6

skeleton

thoracic vertebral transformation ( J:86684 )

• thoracic homeotic transformations: the first thoracic (T1) vertebra develops into the more anterior cervical vertebra C7, and the second thoracic (T2) vertebra develops into T1

• Background Sensitivity: 18% penetrance on a mixed genetic background involving 129S/SvEv and C57BL/6, a lower percentage than on a 129S7/SvEvBrd background