Phenotypes associated with this allele

• Allele Symbol: Hoxa1^tm1Mrc
• Allele Name: targeted mutation 1, Mario R Capecchi
• Allele ID: MGI:1857840
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Hoxa1^tm1Mrc/Hoxa1^tm1Mrc	involves: 129S7/SvEvBrd * C57BL/6J	MGI:2175067
ht2	Hoxa1^tm1Mrc/Hoxa1^+	involves: 129S7/SvEvBrd * C57BL/6J	MGI:2177820
cx3	Hoxa1^tm1Mrc/Hoxa1^tm2Mrc Hoxa2^tm1Mrc/Hoxa2^+	involves: 129S1/Sv * 129S7/SvEvBrd * 129X1/SvJ	MGI:2170580

Genotype
MGI:2175067

hm1

• Allelic Composition: Hoxa1^tm1Mrc/Hoxa1^tm1Mrc
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6J

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

mortality/aging

postnatal lethality, complete penetrance ( J:1776 )

• longest observed period of survival is 3.5 days after birth

perinatal lethality, incomplete penetrance ( J:1776 )

• homozygotes die at or shortly after birth

hearing/vestibular/ear

abnormal outer ear morphology ( J:1776 )

• newborn homozygotes exhibit severe distortion of both the auricle and the external acoustic meatus

abnormal otic vesicle development ( J:1776 )

• at E9.5 and E10.5, the otocyst is displaced rostrally towards the trigeminal ganglion as well as ventrally towards the pharyngeal arches and away from the neural tube

small otic vesicle ( J:1776 )

• at E9.5 and E10.5, all homozygotes display a smaller otocyst

abnormal inner ear morphology ( J:1776 )

• newborn homozygotes display severe defects in inner ear formation

• the interaural space is expanded, distorting the adjacent pons

abnormal cochlea morphology ( J:1776 )

• newborn homozygotes show defective cochlear formation

abnormal inner ear vestibule morphology ( J:1776 )

• newborn homozygotes show defective vestibular formation

absent endolymphatic duct ( J:1776 )

• at E11, the endolymphatic duct is absent

abnormal middle ear morphology ( J:1776 )

absent middle ear ossicles ( J:1776 )

nervous system

abnormal rhombomere morphology ( J:1776 )

• at E9.5-E11.5, all homozygotes display an abnormal rhombomeric pattern, lacking the typical series of bulges that outline each rhombomere

• as a result, the wall on both sides of the neural tube is smooth; however, no delay in neural tube closure is observed at E9.0-E9.5

abnormal hindbrain morphology ( J:1776 )

abnormal pons morphology ( J:1776 )

• newborn homozygotes display a compressed pons, due to accumulation of fluid in the interaural space late in gestation (E19) and at birth

• pons development appears normal up to E18.5; however, certain hindbrain nuclei are not formed

absent facial nuclei ( J:1776 )

• at E13.5-E19, facial nuclei of the hindbrain are either significantly reduced or absent

small facial motor nucleus ( J:1776 )

• at E13.5-E19, facial nuclei of the hindbrain are either significantly reduced or absent

absent superior olivary complex ( J:1776 )

• at E13.5-E19, superior olivary complex nuclei of the hindbrain are either significantly reduced or absent

abnormal cranial ganglia morphology ( J:1776 )

abnormal vestibulocochlear ganglion morphology ( J:1776 )

• at E9.5 and E10.5, 6 of 6 homozygotes show fusion of the facial/vestibulocohlear nerves/ganglia with the trigeminal ganglia on the left but not on the right side (bilateral asymmetry)

• by E13.5, the size of vestibulocochlear ganglion is significantly reduced

abnormal geniculate ganglion morphology ( J:1776 )

• at E9.5 and E10.5, 6 of 6 homozygotes show fusion of the facial/vestibulocohlear nerves/ganglia with the trigeminal ganglia on the left but not on the right side (bilateral asymmetry)

small geniculate ganglion ( J:1776 )

• by E13.5, the size of geniculate (facial) ganglion is significantly reduced or, in some cases, absent

small superior glossopharyngeal ganglion ( J:1776 )

• at E13.5 and E15.5, the size and shape of superior glossopharyngeal ganglia are abnormal

• in addition, the preganglionic connections of superior ganglia with the brainstem and the connections with the inferior ganglia are either reduced or absent

abnormal trigeminal ganglion morphology ( J:1776 )

• at E9.5 and E10.5, 6 of 6 homozygotes show fusion of the facial/vestibulocohlear nerves/ganglia with the trigeminal ganglia on the left but not on the right side (bilateral asymmetry)

small superior vagus ganglion ( J:1776 )

• at E13.5 and E15.5, the size and shape of superior vagus ganglia are abnormal

• in addition, the preganglionic connections of superior ganglia with the brainstem and the connections with the inferior ganglia are either reduced or absent

abnormal cranial nerve morphology ( J:1776 )

abnormal glossopharyngeal nerve morphology ( J:1776 )

• at E10.5, the glossopharyngeal nerve appears poorly developed, and preganglionic connections with the brain are not formed

• the nerves associated with the the glossopharyngeal and vagus ganglia are displaced rostrally along the anteroposterior axis

abnormal vagus nerve morphology ( J:1776 )

• at E10.5, the vagus nerve appears poorly developed, and preganglionic connections with the brain are not formed

• the nerves associated with the the glossopharyngeal and vagus ganglia are displaced rostrally along the anteroposterior axis

absent cochlear nerve ( J:1776 )

• homozygotes exhibit absence of the cochlear nerve

absent vestibular nerve ( J:1776 )

• homozygotes exhibit absence of the vestibular nerve

absent vestibulocochlear nerve ( J:1776 )

craniofacial

absent middle ear ossicles ( J:1776 )

abnormal outer ear morphology ( J:1776 )

• newborn homozygotes exhibit severe distortion of both the auricle and the external acoustic meatus

skeleton

absent middle ear ossicles ( J:1776 )

embryo

abnormal rhombomere morphology ( J:1776 )

• at E9.5-E11.5, all homozygotes display an abnormal rhombomeric pattern, lacking the typical series of bulges that outline each rhombomere

• as a result, the wall on both sides of the neural tube is smooth; however, no delay in neural tube closure is observed at E9.0-E9.5

growth/size/body

abnormal head morphology ( J:1776 )

• stillborn homozygotes have their heads tilted towards their chest

abnormal outer ear morphology ( J:1776 )

• newborn homozygotes exhibit severe distortion of both the auricle and the external acoustic meatus

Genotype
MGI:2177820

ht2

• Allelic Composition: Hoxa1^tm1Mrc/Hoxa1⁺
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6J

normal phenotype

no abnormal phenotype detected ( J:58093 )

• no obvious phenotype

Genotype
MGI:2170580

cx3

• Allelic Composition: Hoxa1^tm1Mrc/Hoxa1^tm2Mrc; Hoxa2^tm1Mrc/Hoxa2⁺
• Genetic Background: involves: 129S1/Sv * 129S7/SvEvBrd * 129X1/SvJ

mortality/aging

neonatal lethality, complete penetrance ( J:58093 )

• die shortly after birth

craniofacial

abnormal cranium morphology ( J:58093 )

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 cranium morphology ( J:58093 )

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