Tyrc
Spontaneous Allele Detail
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| Nomenclature |
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Symbol:
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Tyrc
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Name:
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tyrosinase;
albino
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MGI ID: |
MGI:1855976 |
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Synonyms: |
c |
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Gene:
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Tyr
Location:
Chr7:87427405-87493411 bp, - strand
Genetic Position: Chr7,
49.01 cM
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Tyrc/Tyrc and Tyrc/Tyrc-ch Oca2p/ Oca2p
Show the 3 image(s) involving this allele.
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Mutation
origin |
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Strain of Origin:
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old mutant of the mouse fancy
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Mutation
description |
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Allele
Type: | |
Spontaneous |
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Mutation: | |
Single point mutation |
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Mutation details: The specific mutation in the albino allele is a G to C transversion causing an amino acid change from cysteine to serine. This mutation introduces a DdeI enzyme restriction site. (J:10889, J:40223)
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Inheritance: | |
Recessive |
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Phenotypes
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View phenotypes for all genotypes (concatenated display).
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| Find Mice (IMSR) |
Mouse strains and cell lines available from the
International Mouse Strain Resource
(IMSR)
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Notes |
Tyrc, albino. This very old mutant was already known in Greek and Roman times. Hair and eyes are completely devoid of pigment (J:5436, J:5001, J:30725). The albino mutation affects the amount of tyrosinase, and thus of melanin, in pigment cells, but does not interfere with the production of pigment cells themselves (J:12173, J:13092). Melanocytes with melanosomes showing normal fine structure occur in the retina and hair follicles. Pigment granules are smaller and fewer than normal and completely lack melanin (J:5346, J:5001, J:30725). Tyrosinase is almost absent (J:12173).
Although Tyr is the structural gene for tyrosinase, some albino mutations may affect tyrosinase enzyme regulation rather than structure (J:6611), suggesting that these mutations affect tyrosinase inhibition (J:5346), presumably via control regions of the gene. All the mutant alleles are recessive to wild-type in phenotype, but heterozygotes with wild-type produce intermediate amounts of tyrosinase (J:12173).
Albino-locus mutants with lightly pigmented eyes have a reduced number of fibers of the optic nerve going to the ipsilateral lateral geniculate nucleus of the brain. This is probably a secondary effect of reduced tyrosinase activity or amount of pigment in the pigment epithelium, since genes at other loci that reduce eye pigmentation also cause the same anomaly (J:5436, J:6064).
Abnormal retinal pathways disrupted at the optic chiasm that occur in albinism can be corrected with a Tyr normal transgene (J:22320).
Lipofuscin is a terminal oxidation product pigment that accumulates with age. In a cross of C57BL/6J and BALB/cJ, which differ in cardiac deposition of the pigment, this trait segregated with albinism, and is controlled by the Tyr locus (J:15460).
Tyrc homozygotes do not perform as well as normal in a number of behavioral tests. It is likely that this effect is mediated, at least in part, by defective vision resulting from lack of retinal pigment (J:5470, J:5360, J:5378).
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| References |
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Original: |
J:34484
Detlefsen JA,
"A new mutation in the house mouse"
Am Naturalist 1921 Sep-Oct;55():469-73
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All: |
33 reference(s)
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Analysis Tools
