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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		U
umbrous
MGI:1857322
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
cx1
 		a/a
U/U 		Not Specified MGI:3844552
cx2
 		A/A
U/U 		Not Specified MGI:3844566


Genotype
MGI:3844552
cx1
Allelic
Composition		 a/a
U/U
Genetic
Background		 Not Specified
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
a mutation (166 available); any a mutation (468 available)
U mutation (2 available); any U mutation (2 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
pigmentation
darkened coat color ( J:78801 )
• mice are intense black, darker than mice homozygous for nonagouti and closely resembling mice homozygous for ae
• no yellow hairs on or behind the ears or around the nipples and perineum

integument
darkened coat color ( J:78801 )
• mice are intense black, darker than mice homozygous for nonagouti and closely resembling mice homozygous for ae
• no yellow hairs on or behind the ears or around the nipples and perineum




Genotype
MGI:3844566
cx2
Allelic
Composition		 A/A
U/U
Genetic
Background		 Not Specified
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
A mutation (80 available); any a mutation (468 available)
U mutation (2 available); any U mutation (2 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
pigmentation
darkened coat color ( J:78801 , J:280 )
• the coat is darkened relative to the number of copies of U and a as follows: A/a; U/U > A/a; U/u = A/A; U/U > A/A; U/u = A/a; u/u > A/A; u/u (J:78801)
• U modifies agouti dominance: when U is homozygous there is a marked darkening in A/A mice; when U is heterozygotes the darkening is somewhat less (J:280)

integument
darkened coat color ( J:78801 , J:280 )
• the coat is darkened relative to the number of copies of U and a as follows: A/a; U/U > A/a; U/u = A/A; U/U > A/A; U/u = A/a; u/u > A/A; u/u (J:78801)
• U modifies agouti dominance: when U is homozygous there is a marked darkening in A/A mice; when U is heterozygotes the darkening is somewhat less (J:280)




Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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Send questions and comments to User Support. 		last database update
09/30/2025
MGI 6.24 		The Jackson Laboratory