Phenotypes associated with this allele

• Allele Symbol: mea
• Allele Name: meander tail
• Allele ID: MGI:1856075
• Summary: 3 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	mea/mea	involves: C57BLKS/J * STOCK Tyrp1^b Tyr^c-ch Mitf^Mi a^t Adamts20^bt	MGI:3628440
hm2	mea/mea	involves: STOCK Tyrp1^b Tyr^c-ch Mitf^Mi a^t Adamts20^bt	MGI:3628437
hm3	mea/mea	mixed	MGI:3628438

Genotype
MGI:3628440

hm1

• Allelic Composition: mea/mea
• Genetic Background: involves: C57BLKS/J * STOCK Tyrp1^b Tyr^c-ch Mitf^Mi a^t Adamts20^bt

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

nervous system

abnormal cerebellum morphology ( J:15264 )

• at P14 an abrupt transition from normal to abnormal occurs at what would be lobule VI in wild-type mice with the anterior region being abnormal

abnormal cerebellum development ( J:15264 )

• at P0 the lobules do not appear as well developed as in wild-type mice

• at P6 and P14 the number of lobules is reduced

abnormal cerebellar foliation ( J:15264 )

• at P6 the lateral anterior folia are abnormal with shallow fissures

• at P14 folia I - V appear to be fused into 2 lobules

thin external granule cell layer ( J:15264 , J:32737 )

• at E16 the EGL does not appear to extend as far rostrally as in wild-type mice and at E17 the anterior EGL is dramatically thinner (J:15264)

• at P0 beginning just posterior to the transition line the EGL gradually thins so that in the anterior most regions it consists of only 1 - 2 cell layers (J:15264)

• at P6 in the anterior of the cerebellum the EGL is dramatically thinner than in wild-type mice and in the posterior part of the cerebellum the maximum thickness of the EGL is only 8 rows of cells compared to 10 rows in wild-type mice (J:15264)

• at E17.5 the total number of EGL cells is reduced by 30% with about a 45% reduction detected in the anterior lobe (J:32737)

• at P0 in the anterior lobe the EGL is thin (no more than 2 cell layers thick) to absent with about 80% fewer EGL cells and in the posterior lobe a 20% reduction in the number of EGL cells is seen (J:32737)

• however, no difference in the mitotic index or ability of EGL cells to undergo their final mitosis and differentiate is detected (J:32737)

abnormal cerebellar Purkinje cell layer ( J:15264 )

• at P6 the Purkinje cells are slightly disorganized but still form a distinct layer

• at P14 ectopic Purkinje cells are seen anterior to the transition line at folia VI

thin cerebellar granule layer ( J:15264 , J:32737 )

• at P14 the IGL thins abruptly anterior to the transition line at folia VI (J:15264)

• significant decrease in the density and area of the poorly formed anterior granule cell layer (J:32737)

• in the intermediate lobe there is also a significant decrease in the density and area of the granule cell layer and in the posterior region (lobules VIII - X) there is a small but consistent decrease in the density and area of the granule cell layer (J:32737)

• overall there is a decrease in the number of granule cells; however, the number of Purkinje cells is similar to wild-type (J:32737)

abnormal cerebellar molecular layer ( J:15264 )

• at P6 the molecular is poorly defined

small cerebellum ( J:15264 )

• at P14 the anterior cerebellum is much smaller than in wild-type mice resulting in an overall decrease in the size of the cerebellum

Genotype
MGI:3628437

hm2

• Allelic Composition: mea/mea
• Genetic Background: involves: STOCK Tyrp1^b Tyr^c-ch Mitf^Mi a^t Adamts20^bt

mea/mea mice display cellular defects in the cerebellum

limbs/digits/tail

caudal vertebral fusion ( J:5951 )

• variable degree of ankylosis or fusion of the caudal vertebrae involving as few as 2 up to all of the caudal vertebrae

decreased caudal vertebrae number ( J:5951 )

• in severely affected mice

short tail ( J:5951 )

• severely affected tails are also shorter

kinked tail ( J:5951 )

• variable severity from a slight bend or stiff spot to severe kinks

nervous system

abnormal cerebellum morphology ( J:5951 , J:28105 )

• abnormal anterior cerebellum (J:5951)

• an abrupt transition occurs at the declive between folia VI and VII where the relative normal posterior section meets the abnormal anterior section (J:28105)

abnormal cerebellar lobule formation ( J:28105 )

• the 3 anterior most lobes (lingula cerebelli, lobulus centralis, and culmen) are fused to form 2 lobes

abnormal cerebellar Purkinje cell layer ( J:28105 )

• anterior to the transition line between folia VI and VII Purkinje cells rapidly become disorganized and are found throughout the anterior folia from the outer cortical rim to the white matter

• in this same region Purkinje cells are oriented on their sides or inverted and their dendrites project in all directions including into the white matter

• Bergmann glial fibers lose their radial organization anterior to the transition line between folia VI and VII and in severely affected mice glial processes are markedly reduced in size and number

thin cerebellar granule layer ( J:28105 )

• the IGL thins abruptly anterior to the transition line between folia VI and VII

behavior/neurological

tremors ( J:5951 )

• by 2 weeks of age an unsteadiness of gait often amounting to tremors is seen

growth/size/body

abnormal postnatal growth ( J:5951 )

• tendency to show decreased growth and vigor

skeleton

decreased caudal vertebrae number ( J:5951 )

• in severely affected mice

abnormal thoracic vertebrae morphology ( J:5951 )

• occasionally failure of arch closure or fusion or ankylosis of a few pairs of thoracic vertebrae is seen

abnormal lumbar vertebrae morphology ( J:5951 )

• occasionally failure of arch closure or fusion or ankylosis of a few pairs of lumbar vertebrae is seen

abnormal vertebral arch development ( J:5951 )

• in some cases failure of arch closure is seen mostly involving caudals 4, 5, and 6

• occasionally failure of arch closure of a few pairs of thoracic vertebrae is seen

• occasionally failure of arch closure of lumbar vertebrae is seen

vertebral fusion ( J:5951 )

• severe cases show fusion of dorsal spines of the sacral and proximal caudal vertebrae

caudal vertebral fusion ( J:5951 )

• variable degree of ankylosis or fusion of the caudal vertebrae involving as few as 2 up to all of the caudal vertebrae

reproductive system

reproductive system phenotype ( J:5951 )

N • homozygotes are fertile

Genotype
MGI:3628438

hm3

• Allelic Composition: mea/mea
• Genetic Background: mixed

limbs/digits/tail

short tail ( J:5951 )

• in F2 crosses stock carrying the markers fz and Mlph^ln severely affected tails are also shorter

kinked tail ( J:5951 )

• in F2 crosses stock carrying the markers fz and Mlph^ln variable severity of kinks in the tail are present

• Background Sensitivity: in F2 crosses to a multiple marker P stock (p, Tyrp1^b, a, Myo5a^d, and Bmp5^se) the tail is only slightly different from wild-type

behavior/neurological

abnormal gait ( J:5951 )

• in F2 crosses stock carrying the markers fz and Mlph^ln mice display an unsteady gait

• Background Sensitivity: in F2 crosses to a multiple marker ""P"" stock (p, Tyrp1^b, a, Myo5a^d, and Bmp5^se) the gait is only slightly different from wild-type

paresis ( J:5951 )

• Background Sensitivity: in F2 crosses stock carrying the markers fz and Mlph^ln partial paralysis of one or both hind limbs is seen and is always associated with a severely affected tail but not necessarily with an unsteady gait