Coat Colors and It's Issues

albinism

albinism

occurs when there’s a deactivation of pigments; melanocytes no producing melanin which means no pigment (eyes are pink)

leucism

occurs when there’s a failure on the part of melanoblasts, the precursor to melanocytes

pleiotropism

occurs when one gene influences two or more seemingly unrelated phenotypic traits. such a gene that exhibits multiple phenotypic expression is called a pleiotropic gene

all cats are born deaf, however, the ear canal opens at around 10 days of age

the allele for white dominant (Wd) also causes important hearing cells to degenerate; this only happens with some not all

cats: dominant white

autosomal dominant, DW allele

cats with N/DW genotype will be white and may have some degree of hearing impairment. They will transmit this dominant white variant to 50% of their offspring, and those offspring are expected to be white

cats: white spotting

autosomal dominant, Ws allele

cats with N/Ws genotype will have white spotting. They still transmit this white spotting variant to 50% of their offspring, and those offspring are expected to be white-spotted

cats with Ws/Ws genotype will have white spotting. They will transmit this white spotting variant to all of their offspring, and all of their offspring are expected to have white spotting

cat coloring summary

nearly 75% of cats with two copies of dominant white were deaf and the remainder had at least partial hearing impairment

in cats with a single DW copy and a normal copy for the other allele nearly 60% had normal hearing, 21% were deaf, and 17% had hearing impairment

in cats with one copy of DWand one copy of white spotting (Ws), 1/3 had normal hearing, 1/3 had impairment, and 1/3 were deaf

dogs: piebald

incomplete dominance (some breeds), autosomal recessive (some breeds)

S allele

dogs with N/S genotype have one copy of this piebald variant. They may display no white patterning or some amount of white patterning (varies by breed).
They may transmit this piebald variant to 50% of their offspring

dogs with S/S genotype have two copies of this piebald variant and are expected to display some amount of white patterning. White patterning may be extensive in some breeds, with some individuals being nearly completely white. They will transmit this piebald variant to all of their offspring.

dogs: white spotting

incomplete dominance (some breeds), autosomal recessive (some breeds)

MITF allele

white spotting patterns that occur in many dog breeds do not have a uniform genetic basis. Some white patterns, such as the Irish spotting, are symmetrical with white markings on the undersides, collar, and muzzle, and/or blazes such as seen in Boston Terriers and Corgis

dogs with one copy of the MITF variant

has some white pattern expression, while a dog with 2 copies of the variant displays more extreme white with color only on the head and perhaps a body spot

Boxers and Bull Terriers dogs with 2 copies of the MITF variant

are completely white and dogs

Boxer and Bull Terriers with 1 copy of the MITF varient

mantle (called “flash” in these in these breeds) pattern

mutations in MITF or other white-spotting

genes appear to be present in these breeds that affect the amount of white being expressed

piebald behaves as a recessive trait

that is, 2 copies of piebald are needed to produce white spotting

merle dogs

incomplete dominance

M allele

most merle dogs are M/m

m/m are solid colored

is characterized by irregularly shaped patches with diluted pigment while other patches on the coat are fully pigmented in color

double merles

may have auditory, ophthalmologic, skeletal, and other defects and will transmit a merle variant to all of their offspring

often can have an all-white coat

microphthalmia: double merle puppies may be born with microphthalmia, a condition where the eyes are smaller and don’t form properly

sunburn and skin cancer

deafness and blindness

the gene is semi-dominant

generally considered unethical to breed