Genes - Coat.

Curly Locus

This locus is located on Chromosome #5.

Cu - Curly Dominant.
Effect= The wiskers are slightly curled at the tips. The growth of the coat, especially the guard hairs is impaired, most of which are abscent. The curling is apparent at 2 weeks, after about 10 days it fades becoming downey. By 7 weeks the curl returns. This gene or one linked to it may cause a slight increase in body size and length.
Veterinarian Resources; VetCastle, W.E. and H. D. King. Linkage studies of the rat VII. Shaggy, a new dominant Journal of Heredity Volume: 38 Pages: 341-344 Year: 1947. Robinson, Roy. Genetics of the Norway Rat Pergamun Press 1965. Chapter II
cu-1 - Wild Type Recessive.
Effect = None.

Curly-1 Locus

Cu-1 - Curly 1 dominant.
Effect = Wiskers are short and bent. Most guard hairs are missing, the few remaining are curly. Creates a more significant curling effect than Cu or k, but generally very similar to Cu.
Veterinarian Resources; Castle, W.E. and H. D. King. Linkage studies of the rat VII. Shaggy, a new dominant Journal of Heredity Volume: 38 Pages: 341-344 Year: 1947. Robinson, Roy. Genetics of the Norway Rat Pergamun Press 1965. Chapter II
cu-1 - Wild Type Recessive.
Effect = None.

Cowlicked Locus

Cw - Wild Type Dominant.
Effect = None.
cw - Cowlicked recessive.
Effect = Causes a whorl of hair on the mid dorsal line, usually in the middle of the back, sometimes on the head. On the head it usually is less noticeable- just a tuft of hair running forwards instead of back to the rump as most hairs run... When on the back a full whorl is usually seen.
Veterinarian Resources; Robinson, Roy. Genetics of the Norway Rat Pergamun Press 1965. Chapter II

Fuzzy Locus

This locus is on Chromosome #1 and is linked to albino (c) with a 18.13 +/- 3.05 percent recombination. Also, The map position of fz in the rat corresponds to that of fr (frizzy) in the mouse, suggesting homology between these loci in the 2 species.

Fz - Wild Type Dominant.
Effect = None.
fz - Fuzzy Recessive.
Effect =First hair coat develops normally, then failure of coat to develop after first molt other than a few straggling guard hairs; both sexes fertile.
Veterinarian Resources; Stock and Strain Listhttp://www.nih.gov/od/ors/dirs/vrp/s&slst.htm#ratinbred. Ferguson, Frederick G, Et Al. Three Variations of Hairlessness Associated with Albanism in the Laboratory Rat. Laboratory Animal Science Vol.29 P. 459-465 yr. 1979 Greaves, J. H. and Ayres, P. B.Fuzzy: a genetic marker for warfarin resistance in the Norway rat. Laboratory Animals 19:145-147 (1985) Palm, J. and Ferguson, G. Fuzzy, a hypotrichotic mutant in linkage group I of the Norway rat. Journal of Heredity 67:284-288 (1976)

Hairless Locus

This Locus is on Chromosome #3

Hr - Wild Type Dominant.
Effect =None.
hr - Hairless Recessive.
Effect = Adult skin is thick, wrinkled. Coat looks normal until 2-3 weeks, then hair begins falling out. Coat reappears at 40-45 days. Cycle repeates 1 - 5 times. Has enlarged kidnies, adrenals. There maybe an allele to hr with similar hairlessness appearance and also associated extra long and curved nails, and sterility in females.
Veterinarian Resources; Ferguson, Frederick G, Et Al. Three Variations of Hairlessness Associated with Albanism in the Laboratory Rat. Laboratory Animal Science Vol.29 P. 459-465 yr. 1979 Robinson, Roy. Genetics of the Norway Rat Pergamun Press 1965. Chapter II, 2nd allele on pg 52

Kinky Locus

Located on Chromosome #4, near stub-tail

K - Wild Type Dominant.
Effect = None.
k - Kinky recessive rex.
Effect = Wiskers curled. Wooly short dense juevinile fur. Short and rough and some thinning patches by adult hood on shoulders, hips.
Veterinarian Resources; Castle, W.E. and H. D. King. Linkage studies of the rat VII. Shaggy, a new dominant Journal of Heredity Volume: 38 Pages: 341-344 Year: 1947.

Masked Locus

The mutation at this locus is likely not to be seen by the pet fancier. However, the Dr. Schwartz book, "Rats: A Complete Introduction" from TFH publishing, lists this mutation among others known to the fancy, casually, apparently prompting readers to think that this is a variety of fancy rat. Some of these peopel have contacted me wondering if thsi was the "masked marking" standardized in soem clubs (white rat with coloured stripe over eyes) or a hairless rat with fur just on the face. Actually, its none of these, but rather it is a product of an X-ray experiment in a lab and is so named for a trait that much of the fancy world would probably be disgusted with. This entery is simply to answer those curious about the misleading listing they saw in the above mentioned book.

Mk - Wild Type Dominant.
Effect = None.
mk - Masked Recessive.
Effect = X-ray-induced in the rat. The rat's eyelids are swollen, often to the point of closure, and its face is partially covered by a brownish crust (or "mask"). The eye problems and mask is due to an infection of Pasteurella pneumotropica to which the rat is genetically predisposed to acquiring. Chronic blepharitis was also accompanied by alopecia that appeared as bare patches across the mutant's back.
Veterinarian Resources; Kent RL, Lutzner MA, Hansen CT . The masked rat. An X-ray induced mutant with chronic blepharitis, alopecia, and pasteurellosis. J Hered 1976 Jan-Feb;67(1):3-5

Naked Locus

Located on Chromosome #3

N - Wild Type Dominant.
Effect = None
n - Naked Recessive hairloss.
Effect = Twisted wiskers. Juevenile coat lost at 3 weeks and skin is yellow and dry/rough. Skin later turns pink and soft. fuzz grows at 4 weeks, quickly lost and cycle repeats up to 6months. Fuzz reforms most on legs, chest, tailbase. Smaller in size than non-affected littermates. Epistatic to ("masks") the hairless gene (hr) from age 6 weeks onward (hr also on this chromosome)- meaning that hr/hr n/n rats do not develop the yellow scaley skin associated with hairless (hr).
Veterinarian Resources; Ferguson, Frederick G, Et Al. Three Variations of Hairlessness Associated with Albanism in the Laboratory Rat. Laboratory Animal Science Vol.29 P. 459-465 yr. 1979 Robinson, Roy. Genetics of the Norway Rat Pergamun Press 1965. Chapter II

Rex Locus

Re - Rex Dominant.
Effect = When Heterozygous, the vibrissae are bent, the coat is shorter than normal and has a harsh texture. Guard hairs are few or absent. When Homozygous, the coat is more severely affected, displaying a transient baldness at about five weeks of age.
Veterinarian Resources; Robinson R. Rex mutant in the Norway rat. Journal of Heredity. 1981 Mar; 72(2): 131-132.
re - Wild Type Recessive.
Effect = None.

Rnu Locus

Probably best known to those who have heard of it in the fancy as the "Rowlette Nude" (for which Rnu stands for). The name and symbol of this locus was updated scientifically so that current referrences in journals may read Whn which stands for "Winged-helix nude". The chromosomal location for this locus is 10 q24-q32

Rnu - Wild Type Dominant.
Effect = None.
rnu - Rowlette nude.
Effect = Poor immunity due to depressed T-cell function and replacement of thymus with brown fat, though an abnormal thymic rudiment is present. Affected animals are nude. Most (though not all) nude females are unable to nurse. Because of this, they are more likely than normal rats to cannibalize their young, believing that they have no way to support them.
Veterinarian Resources; J. M. Cash, et al. Genetic mapping of the athymic nude (RNU) locus in the rat to a region chromosome-10. Mammal. Genome Volume: 4 Pages: 37-42 Year: 1993 T. Kuramotoet al. Regional mapping of the Rowett nude gene (RONO) to rat chromosome 10q24©q32 by localizing linked SYB2 and GH loci. Cytogenet. Cell Genet. Volume: 63 Pages: 107-110 Year: 1993 Stock and Strain Listhttp://www.nih.gov/od/ors/dirs/vrp/s&slst.htm#ratinbred

Shaggy Locus

Located on Chromosome #5 and Linked to Curly-1

Sh - Shaggy Dominant.
Effect = Curling effect is between Cu (less curly) and Cu1(most curly), though more similar to Cu than Cu1. A Cu/+ Sh/+ rat is even more curly furred than either a plain Cu or plain Sh rat.
Veterinarian Resources; Castle, W.E. and H. D. King. Linkage studies of the rat VII. Shaggy, a new dominant Journal of Heredity Volume: 38 Pages: 341-344 Year: 1947.
sh - Wild Type
Effect = None.

Shorn Locus

Shn - Wild Type.
Effect = None.
shn - Shorn Recessive.
Effect = Causes an almost complete absence of normal hair. Distinct from fuzzy, hairless, and Rowett nude, and is not closely linked with any of these markers or with albino.
Veterinarian Resources; Moemeka AN, Hildebrandt AL, Radaskiewicz P, King TR. Shorn (shn): a new mutation causing hypotrichosis in the Norway rat. Journal of Heredity. 1998 May;89(3):257-260

Tremor Locus

Tr - Wild Type Dominant.
Effect = None.
tr - Tremor Recessive.
Effect = Causes epilepsy (whole body tremors), bent overhairs, bent whiskers, and spongiform encephalopathy of the central nervous system. Affected rats are Steril.
Veterinarian Resources; Serikawa T, Yamada J Epileptic seizures in rats homozygous for two mutations, zitter and tremor. . J Hered 1986 Nov - Dec ; 77 (6) : 441-4

Wavy Locus

Wv - Wild Type Dominant.
Effect = None.
wv - Wavy Recessive.
Effect = Wavy coat.
Veterinarian Resources; Greaves JH. Wavy: a new recessive rexoid mutant in the Norway rat. Journal of Heredity. 1981 Jul; 72(4): 291-292. Robinson R. Linkage studies of wavy in the Norway rat, Rattus norvegicus. Genetica. 1988 Jul 31; 77(1): 79-80.

Zitter Locus

This locus is located on Chromosome #3.

Zi - Wild Type Dominant.
Effect = None.
zi - Zitter Recessive.
Effect = Causes epilepsy (whole body tremors), bent overhairs, bent whiskers, and spongiform encephalopathy of the central nervous system.
Veterinarian Resources; Yamada T, Mori M, Hamada S, Serikawa T, Yamada J Assignment of tremulous body mutant gene zitter (zi) to linkage group IV of the rat (Rattus norvegicus). J Hered 1989 Sep-Oct;80(5):383-6 Serikawa T, Yamada J Epileptic seizures in rats homozygous for two mutations, zitter and tremor. J Hered 1986 Nov-Dec;77(6):441-4


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