Analysis Tools
nervous system
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• the vestibular ganglion does not extend much beyond the superior border of the saccular macula and has fewer, less densely packed cells
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• the superior vestibular nerve enters the saccular macula near the center of the macula, rather than the dorsal border
• along with the utricular macula, the utricular branch of the superior vestibular nerve is entirely missing
• the pathway of the nerve from the superior vestibular ganglion to the crista rarely takes a normal course along the base of the utricle, but often passes through the otic capsule and tympanic cavity, and is often branched
• the lateral vestibular nerve rarely follows a normal course, and the nerve is very thin in instances when the crista is small
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hearing/vestibular/ear
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• heterozygotes are not deaf, the cochlea appears normal
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• by embryonic day 10 the acoustic ganglion is smaller and does not curve around to reach the anterior aspect of the vesicle, and the epithelium on the antero-lateral aspect is not thickened as in normal embryos
• by embryonic day 11 the nerve that would normally innervate the epithelium destined to become the utricular macula and superior lateral cristae is deficient and aberrent or entirely lacking
• by embryonic day 12 the utriculo-saccular folds are abnormal in appearance, the utricular nerve is always missing, the nerves of the superior and lateral cristae are sometimes missing, and the accessory nerve from the superior vestibular ganglion sometimes branches to one of the critae and is always thinner than normal
• by embryonic day 13 the shape and size of the utricle and saccule are abnormal, the utricle has no nerve supply and no macula, the nerves of the superior and lateral semicircular ducts are often missing, and the utriculo-saccular fold is thicker than normal, slants in the medial direction, and is foreshortened posteriorly
• by embryonic day 16 the absence of the utricular valve and saccular duct is evident
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• the majority of heterozygotes have a unilateral or bilateral severe narrowing, complete obliteration of the lumen, or absence of the ampullar end of the lateral semicircular duct and constriction or absence of the bony canal in this region
• this abnormality is more severe in the lateral than the superior semicircular canal
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• when narrowing is found in the superior semicircular duct, the crista is either missing or poorly formed, and even when normal in appearance the crista is often shifted in its location
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• the majority of heterozygotes have a unilateral or bilateral severe narrowing or complete obliteration of the lumen of the ampullar end of the superior semicircular duct and constriction of the bony canal in this region
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• in all dancer mice the utricular macula and utricular branch of the superior vestibular nerve are entirely missing
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small utricle
(
J:5022
)
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• the utricle is smaller than normal, particularly dorso-ventrally
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• the saccule, affected in all heterozygotes, does not extent dorsally as far as the utricle and is attached to the utricle by a thick strand of cells without any lumen
• the free wall of the saccule is sometimes highly convoluted
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• the saccule is smaller and narrower than normal
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behavior/neurological
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• when lifted by the tail at approximately 3 days of age a heterozygote will hump its back instead of arching it, retract the front legs and bend the head toward the belly
• when lifted by the tail as an adult, a heterozygote will twist and turn and throw its body about
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head tossing
(
J:5022
)
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• heterozygotes make jerking movements of the head in both horizontal and vertical planes
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abnormal gait
(
J:5022
)
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• by 2 weeks of age heterozygotes decelop a weaving gait with bi-directional circling
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hyperactivity
(
J:5022
)
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• evident by 1 week of age and increasing by 2 weeks of age
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• similar circling behavior as that of waltzer mutants but with less head movement
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growth/size/body
cleft palate
(
J:7364
)
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• Background Sensitivity: does not occur spontaneously but can be induced on this background by treatment of pregnant mothers with 6-aminonicotinamide
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• smaller than wild-type littermates by 1 week of age
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pigmentation
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• most dancer mutants have a white spot, varying in size, in the middle of the head
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craniofacial
cleft palate
(
J:7364
)
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• Background Sensitivity: does not occur spontaneously but can be induced on this background by treatment of pregnant mothers with 6-aminonicotinamide
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digestive/alimentary system
cleft palate
(
J:7364
)
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• Background Sensitivity: does not occur spontaneously but can be induced on this background by treatment of pregnant mothers with 6-aminonicotinamide
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integument
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• most dancer mutants have a white spot, varying in size, in the middle of the head
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skeleton
