Analysis Tools
mortality/aging
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• in contrast to Prrx1tm1Tex homozygotes which live up to 24 hrs, double homozygotes die within 1 hr after birth
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respiratory system
skeleton
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• the lateral wall of the skull is composed of a sheet of ectopic cartilage, as squamosal and zygomatic bones are absent
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• the oval window is displaced medially
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• most of Meckel's cartilage is absent; only the distal tip and a small proximal part is present
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• the entire zygomatic arch is absent
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• the styloid process is abnormally fused to the hyoid bone
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• mandibular incisors are either absent (38%) or a single median incisor is observed (42%)
• in contrast, molars appear unaffected
• in some cases, a rudimentary second incisor is observed (12%)
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• at E18.5, ~8% of double homozygotes show a cleft mandible and tongue
• dentaries are shortened and their distal tips fused
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• at E12.5, the lower jaw is much shorter than normal
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• the malar (zygomatic) process of the maxilla is absent
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micrognathia
(
J:50488
)
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• severely reduced lower jaw
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• malformed malleus, with an ectopic process immediately distal from the malleus
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• the stylohyoid ligament is chondrified and connects the stapes and the styloid process to the lesser horn of the hyoid bone; as a result, the stapes is displaced
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• tarsal bones are fused with a variable pattern
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bowed radius
(
J:50488
)
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• the triangular, which articulates with the ulna and the carpal bones, is laterally truncated, and the pisiform is fused to the ulna
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bowed ulna
(
J:50488
)
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• the tibial diaphysis bulges out and forms a cap of bone under which the proximal and distal epiphyseal cartilages are connected
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• an ectopic cartilaginous element is seen between the first and second metarsal in the hindfoot
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• in newborns, the zone of pre- and hypertrophic cartilage cells are severely shorterned in the zeugopods
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• ~60% of newborn double homozygotes show partial or complete absence of the spine of the scapula
• the extent of this defect is often variable between left and right sides of the same animal, and is first evident at E13.5
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• a hole is noted in the xyphoid process of the sternum
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• the pubic symphysis is absent, resulting in a gap between the pubic bones
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• all double homozygotes show absence of the dorsal processes of thoracic vertebrae
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• all double homozygotes show absence of the dorsal processes of the cervical atlas
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• all double homozygotes show absence of the dorsal processes of the cervical axis
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• all double homozygotes show absence of the dorsal processes of lumbar vertebrae
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• neural arches spread out laterally
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• the dorsal processes of the thoracic, lumbar and cervical vertebrae are absent
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• the lateral wall of the skull is composed of a sheet of ectopic cartilage, as squamosal and zygomatic bones are absent
• an ectopic cartilaginous element is seen between the first and second metarsal in the hindfoot
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• the entire stylohyoid ligament is chondrified, and connects the stapes and the styloid process to the lesser horn of the hyoid bone
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• delayed ossification of the radius and tibia
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limbs/digits/tail
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• the first digit of the forefoot is broader and its phalanges are thinned centrally
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polydactyly
(
J:50488
)
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• an extra digit is observed on the posterior side of the forefoot and is often thinner than other digits
• the morphology of the extra digit ranges from a fragment of a metacarpal to a complete metacarpal with two phalages
• the metacarpal of the extra digit articulates with the triangular and the ulna
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• tarsal bones are fused with a variable pattern
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• downward pointing of forelimbs
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• neonatal forelimb zeugopods are severely shortened, with their cartilaginous precursors already shortened and thickened at E13.5
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bowed radius
(
J:50488
)
|
• the triangular, which articulates with the ulna and the carpal bones, is laterally truncated, and the pisiform is fused to the ulna
|
bowed ulna
(
J:50488
)
|
• neonatal hindlimb zeugopods are severely shortened, with their cartilaginous precursors already shortened and thickened at E13.5
|
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• the tibial diaphysis bulges out and forms a cap of bone under which the proximal and distal epiphyseal cartilages are connected
|
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• an ectopic cartilaginous element is seen between the first and second metarsal in the hindfoot
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craniofacial
|
• the lateral wall of the skull is composed of a sheet of ectopic cartilage, as squamosal and zygomatic bones are absent
|
|
• the oval window is displaced medially
|
|
• most of Meckel's cartilage is absent; only the distal tip and a small proximal part is present
|
|
• the entire zygomatic arch is absent
|
|
• the styloid process is abnormally fused to the hyoid bone
|
|
• mandibular incisors are either absent (38%) or a single median incisor is observed (42%)
• in contrast, molars appear unaffected
• in some cases, a rudimentary second incisor is observed (12%)
|
|
• at E18.5, ~8% of double homozygotes show a cleft mandible and tongue
• dentaries are shortened and their distal tips fused
|
|
• at E12.5, the lower jaw is much shorter than normal
|
|
• the malar (zygomatic) process of the maxilla is absent
|
micrognathia
(
J:50488
)
|
• severely reduced lower jaw
|
|
• malformed malleus, with an ectopic process immediately distal from the malleus
|
|
• the stylohyoid ligament is chondrified and connects the stapes and the styloid process to the lesser horn of the hyoid bone; as a result, the stapes is displaced
|
|
• tongue inserts through the cleft palate into the nasal cavity, obstructing the airway
|
pointed snout
(
J:50488
)
|
• absence of external ears
• an ectopic crescent-shaped cartilaginous element is found in the remnant of the auricle
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hearing/vestibular/ear
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• the oval window is displaced medially
|
|
• malformed malleus, with an ectopic process immediately distal from the malleus
|
|
• the stylohyoid ligament is chondrified and connects the stapes and the styloid process to the lesser horn of the hyoid bone; as a result, the stapes is displaced
|
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• absence of external ears
• an ectopic crescent-shaped cartilaginous element is found in the remnant of the auricle
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• only a remnant of the lateral duct found in a small cavity in the otic capsule is observed
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• in newborns, the entire otic capsule is reduced due to reduced outgrowth of the ducts of the membranous labyrinth
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homeostasis/metabolism
digestive/alimentary system
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• tongue inserts through the cleft palate into the nasal cavity, obstructing the airway
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nervous system
spina bifida
(
J:50488
)
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• all double homozygotes exhibit spina bifida, as neural arches spread out laterally
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embryo
spina bifida
(
J:50488
)
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• all double homozygotes exhibit spina bifida, as neural arches spread out laterally
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growth/size/body
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• mandibular incisors are either absent (38%) or a single median incisor is observed (42%)
• in contrast, molars appear unaffected
• in some cases, a rudimentary second incisor is observed (12%)
|
|
• tongue inserts through the cleft palate into the nasal cavity, obstructing the airway
|
pointed snout
(
J:50488
)
|
• absence of external ears
• an ectopic crescent-shaped cartilaginous element is found in the remnant of the auricle
|
