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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Hoxa1tm2Mrc
targeted mutation 2, Mario R Capecchi
MGI:1858002
Summary 4 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
cx1
 		Hoxa1tm1Mrc/Hoxa1tm2Mrc
Hoxa2tm1Mrc/Hoxa2+ 		involves: 129S1/Sv * 129S7/SvEvBrd * 129X1/SvJ MGI:2170580
cx2
 		Hoxa1tm2Mrc/Hoxa1tm2Mrc
Hoxa2tm1Mrc/Hoxa2tm1Mrc 		involves: 129S1/Sv * 129X1/SvJ MGI:2170585
cx3
 		Hoxa1tm2Mrc/Hoxa1+
Hoxa2tm1Mrc/Hoxa2tm1Mrc 		involves: 129S1/Sv * 129X1/SvJ MGI:3043810
cx4
 		Hoxa1tm2Mrc/Hoxa1+
Hoxa2tm1Mrc/Hoxa2+ 		involves: 129S1/Sv * 129X1/SvJ MGI:3043811


Genotype
MGI:2170580
cx1
Allelic
Composition		 Hoxa1tm1Mrc/Hoxa1tm2Mrc
Hoxa2tm1Mrc/Hoxa2+
Genetic
Background		 involves: 129S1/Sv * 129S7/SvEvBrd * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm1Mrc mutation (0 available); any Hoxa1 mutation (13 available)
Hoxa1tm2Mrc mutation (0 available); any Hoxa1 mutation (13 available)
Hoxa2tm1Mrc mutation (0 available); any Hoxa2 mutation (19 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:58093 )
• die shortly after birth

craniofacial
abnormal basioccipital bone morphology ( J:58093 )
• slight restructuring and reduced ossification
absent stapes ( J:58093 )
• absence of the stapes in many cases
small middle ear ossicles ( J:58093 )
• reduced middle ear apparatus
small ears ( J:58093 )
• reduced pinna of ear

hearing/vestibular/ear
absent stapes ( J:58093 )
• absence of the stapes in many cases
small middle ear ossicles ( J:58093 )
• reduced middle ear apparatus
small ears ( J:58093 )
• reduced pinna of ear

respiratory system
respiratory failure ( J:58093 )
• never initiate normal breathing patterns resulting in rapid death

skeleton
abnormal basioccipital bone morphology ( J:58093 )
• slight restructuring and reduced ossification
absent stapes ( J:58093 )
• absence of the stapes in many cases
small middle ear ossicles ( J:58093 )
• reduced middle ear apparatus

growth/size/body
small ears ( J:58093 )
• reduced pinna of ear




Genotype
MGI:2170585
cx2
Allelic
Composition		 Hoxa1tm2Mrc/Hoxa1tm2Mrc
Hoxa2tm1Mrc/Hoxa2tm1Mrc
Genetic
Background		 involves: 129S1/Sv * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm2Mrc mutation (0 available); any Hoxa1 mutation (13 available)
Hoxa2tm1Mrc mutation (0 available); any Hoxa2 mutation (19 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:58093 )
• die shortly after birth

hearing/vestibular/ear
abnormal middle ear ossicle morphology ( J:58093 )
• severe patterning defects in the middle ear and associated skeleton
small middle ear ossicles ( J:58093 )
• reduced size of middle ear elements
absent outer ear ( J:58093 )
• pinna of ear almost entirely absent

skeleton
abnormal middle ear ossicle morphology ( J:58093 )
• severe patterning defects in the middle ear and associated skeleton
small middle ear ossicles ( J:58093 )
• reduced size of middle ear elements

nervous system
abnormal hindbrain morphology ( J:58093 )
• extensive hindbrain defects affecting breathing

craniofacial
abnormal middle ear ossicle morphology ( J:58093 )
• severe patterning defects in the middle ear and associated skeleton
small middle ear ossicles ( J:58093 )
• reduced size of middle ear elements
absent outer ear ( J:58093 )
• pinna of ear almost entirely absent

growth/size/body
absent outer ear ( J:58093 )
• pinna of ear almost entirely absent




Genotype
MGI:3043810
cx3
Allelic
Composition		 Hoxa1tm2Mrc/Hoxa1+
Hoxa2tm1Mrc/Hoxa2tm1Mrc
Genetic
Background		 involves: 129S1/Sv * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm2Mrc mutation (0 available); any Hoxa1 mutation (13 available)
Hoxa2tm1Mrc mutation (0 available); any Hoxa2 mutation (19 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:58093 )
• die shortly after birth of dehydration

behavior/neurological
abnormal suckling behavior ( J:58093 )
• unable to suckle

craniofacial
cleft secondary palate ( J:58093 )
• extent of cleft secondary palate not as great with decreased functional Hoxa1

digestive/alimentary system
cleft secondary palate ( J:58093 )
• extent of cleft secondary palate not as great with decreased functional Hoxa1

growth/size/body
cleft secondary palate ( J:58093 )
• extent of cleft secondary palate not as great with decreased functional Hoxa1




Genotype
MGI:3043811
cx4
Allelic
Composition		 Hoxa1tm2Mrc/Hoxa1+
Hoxa2tm1Mrc/Hoxa2+
Genetic
Background		 involves: 129S1/Sv * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm2Mrc mutation (0 available); any Hoxa1 mutation (13 available)
Hoxa2tm1Mrc mutation (0 available); any Hoxa2 mutation (19 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
normal phenotype
no abnormal phenotype detected ( J:58093 )
• viable and fertile




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Send questions and comments to User Support. 		last database update
09/30/2025
MGI 6.24 		The Jackson Laboratory