Ragged is
a single, recessive trait (rg) (Noguchi 1990). Another variety of rat that is similar to double rex rats is patchwork rats. REX – With curly hair and curly whiskers. Promoting ethical breeding and responsible ownership of rats. This variety of rats have the typical wild type of rat ears. Whn is required
for the primordial thymus tissue to differentiate into a fully-formed
normal thymus (Lee et al. Whn is involved in epithelial
differentiation. Besides coat type, there are also hairless, tailless, and big-eared (dumbo) fancy rat varieties. Their genetic
underpinnings are speculative at this point.
How are rex and wavy related to curly-1, curly-2, kinky and
shaggy? During this time you should interact with your rats through play and some cuddle time. Bottom: young adult male fuzzy rat (Palm and Ferguson
1976). Debbie "The Rat Lady" Ducommun, internationally recognized expert on rats and founder of the Rat Fan Club, says “a reputable breeder working to breed pet rats, and not feeder rats, is a very good source for healthy and friendly rats.”. All varieties of rats can come in any colour variant. They can be seen with a fairly blunt nose, small eyes, and small ears that have hair at their back. This also means that there can be more than one rat in a single variety. The natural colour of rats is known as agouti, which is a brown colour made by banded hairs in black, grey, brown, and orange. Litter needs to be replaced at least weekly, and the cage should be washed on a regular basis. Rats are generally quite healthy, but like other pets they seem to be prone to a specific set of problems. In any case, they are very friendly and tend to become much-tamed pets.
These four mutations are currently
thought to be extinct: Normal (left) and Curly-2
(right) rats (Gregory and Blunn
1936). The hairless (hr) mutation has not yet been
found in rats, however. Nude rats therefore do not develop a thymus
(Festing et al. Other effects: nude rats have no functioning thymus.
Since having a tail is important for maintaining body balance, Manx rats may face difficulty in managing themselves and may need additional care. Also, a particular
coat may have a number of possible underlying causes, so use caution
when extrapolating from this document to your pet rats. Mutations affecting hair production:
the hairless mutations, Charles River "hairless" and fuzzy
(fz), Mutations affecting hair shape and
length: the rexoid mutations, J.
Mulrooney, R. Rollin, and K. Martin-Troy, The
Genotypes of Recessive Hairlessness. According to the American Fancy Rat and Mouse Association (AFRMA): At present, all rats are shown in seven varieties: STANDARD – With short, smooth, glossy hair. The pelage of rex heterozygotes (Rere, known as rex)
appears wooly and unkempt. The hair shaft consists of three layers. Unfortunately, the four variants curly-1, curly-2, kinky and
shaggy appear to be extinct. Then
some of them stop multiplying and join the growing column of the hair
shaft. After the follicle shuts down, the follicle enters the
telogen phase, a resting phase during which the hair is free
to fall out.
By and large,
I have tried to steer clear of rat standards and "official" coat
names, and have instead focused on my area of interest: the biology
of coat production.
1996, Baxter and Brissette 2002).
A mutation called shorn may involve an
error in the gene that codes for keratin, which leads to hairlessness
(ongoing research, T.
King, J.
Mulrooney, R. Rollin, and K. Martin-Troy). However, if you think that this is all there is to the rat world, then you are absolutely wrong. Rex and Wavy rats can be bred
together. However, the
last four mutations (curly-1, curly-2, kinky, and shaggy) appear to
be extinct in laboratory rats (Greaves 1981).
It is very important that you establish a relationship with a veterinarian who has experience treating rats. T-lymphocytes mature in the thymus, so without a thymus one large
branch of the immune system is non-functioning. Dwarf rats are a very popular rat variety. This is mainly due to the presence of male hormones which make the rat bucks produce an orange grease from their skin, known as buck grease. What sets fancy rats apart is the fact that they have been bred over many generations for their good looks and pleasant natures.
The Charles River hairless and
fuzzy (fz) mutations in the rat
causes a thick buildup of corneocytes. 2002). The main concern of owning hairless rats is their health. And, as Ducommun puts it, “since club members love rats and love to talk about them, they can be supportive friends for families just getting started in rats.”, A nest box and bedding that the rats can shred and manipulate (e.g., paper towels or commercial bedding material), Wood blocks or other safe objects for chewing. Their hairs are easier to pluck out than in normal
rats and rex rats. Any rat variety, whether it is a body type, coat type, or a colour type, will require proper care and maintenance. When it comes to blue rats, there are mainly of two types, Russian blue and Slate blue. They appear to be smaller and slimmer when compared to other rat varieties. However, in some pet rats, this gene is now absent, making them non-agouti. Specifically, chronic
nephrosis started around 8 weeks of age in both sexes, but neither
sex was obviously affected for several months.
Whn is a key regulatory factor which maintains the balance
between keratinocyte growth and differentiation in the skin
(Brissette et al. The coat starts out soft in very young
rats, and a rough texture develops through molts in adolescence and
adulthood. However, that isn’t true at all. For instance, some associations such as the National Fancy Ray Society in the UK have completely banned hairless rats from their display. To make things even more complicated, mice also
have a gene called fuzzy, but it isn't related to the rat's
fuzzy. But you have other options if you are simply in the market for a new fuzzy friend.
Rex coats tend to be
thicker and more curly than those of wavy rats, though the two types
can be hard to distinguish reliably.
In some cases, a rat may look like an Albino, but it might actually be a pink-eyed white rat, which simply has so many dilutions that it looks like an Albino.
In the wild, they all feature one body shape, one type of coat, and are mostly of the same colour. Homozygous shorn (shn/shn) at next to
a heterozygous shn/+ littermate at 4 weeks. 1978. This has resulted in beautiful animals who truly enjoy contact with people. If the whn protein is disrupted, as it is in the Rowlett
nude (rnu) mutation in rats, the primordial cells of the thymus
fail to differentiate into the different mature cell types of the
normal thymus. 2002). I've written up a summary
of how mouse hr works, but remember that rats don't have
this mutation. Top row: Curly-2, Curly-1,
and Shaggy (all heterozygotes). Even the head appears to be big and round, but that’s just a visual trick because of their ear position. Apart from this, people also believe that Dumbo rats are friendlier and have a longer lifespan when compared to the standard rats.
1996, Baxter and Brissette
2002). Dedicated fancy rat breeder focused on producing Seal Point Black Eyed Siamese, Burmese, and Black self rats. Therefore, make sure you are ready for their responsibility well before you choose what variety of rat you wish to have. The rexoid mutations slow the rate of growth
during the anagen phase, which results in shorter hair. An Albino rat can be identified by its white body and pink eyes. The rexoid mutations slow the rate of hair growth. According to Ducommun, “the most common health problems in rats include respiratory infections and mammary tumors in the females.
There are three types: 2002). 2002). Fancy rats come in 7 different varieties, mostly related to the thickness and texture of the coat. An agouti-based rat almost looks like a fawn with a beautiful light colour and a lighter belly. If a mutation occurs in that cascade, the effects may be very
diverse, from hair to skin to glands.
This is all rather confusing, so here's a table showing the
correspondence between the different mutations in rats and mice: Rowlett Nude (rnu), New Zealand Nude
(nznu), Slowing the rate of hair
growth: the rexoid mutations (rex and
wavy). Sometimes, during a rat's molt
from one coat to the next, you can see funny coat patterns
particularly on the rat's face or forehead, formed by the interface
between the new and old coats. Genetics: The shorn locus has been mapped to a
narrow area of Chromosome 7 (Hall et al. In 1981 four additional rexoid variants were known in Norway rats
(Robinson 1981, Greaves 1981). Blue rats are generally cast with genes which are bluish silver, some very light, and other dark genes depending on which blue and other dilutes the rat may have.