A piebald or pied animal is one that has a spotting pattern of large unpigmented,
usually white, areas of hair, feathers, or scales and normally pigmented
patches, generally black. The colour of the animal's skin underneath its coat is
also pigmented under the dark patches and unpigmented under the white patches.
This alternating colour pattern is irregular and asymmetrical. Animals with
this pattern may include horses, dogs, birds, cats, pigs, and cattle, as well
as snakes such as the ball python. Some animals also exhibit colouration of the
irises of the eye that match the surrounding skin. The underlying genetic
cause is related to a condition known as leucism.
Etymology The word "piebald" originates from a
combination of "pie," from "magpie," and "bald", meaning "white patch" or spot.
The reference is to the distinctive black-and white plumage of the magpie.
Horses In British English piebald and skewbald
are together known as coloured. In North American English, the term for this
colouring pattern is pinto, with the specialized term "paint" referring
specifically to a breed of horse with American Quarter Horse or Thoroughbred
bloodlines in addition to being spotted, whereas pinto refers to a spotted horse
of any breed. In American usage, horse enthusiasts usually do not use the term
"piebald," but rather describe the colour shade of a pinto literally with
terms such as "black and white" for a piebald, "brown and white," or "bay and
white," for skewbalds, or color-specific modifiers such as "bay pinto", "sorrel
pinto," "buckskin pinto," and such. Genetically, a piebald horse begins with
a black base coat colour, and then the horse also has an allele for one of
three basic spotting patterns overlaying the base colour. The most common
coloured spotting pattern is called tobiano, and is a dominant gene. Tobiano
creates spots that are large and rounded, usually with a somewhat
vertical orientation, with white that usually crosses the back of the horse,
white on the legs, with the head mostly dark. Three less common spotting genes
are the sabino, frame and splash overo genes, which create various patterns
that are mostly dark, with jagged spotting, often with a horizontal
orientation, white on the head. The frame variant has dark or minimally
marked legs. The sabino pattern can be very minimal, usually adding white that
runs up the legs onto the belly or flanks, with "lacy" or roaning at the
edge of the white, plus white on the head that either extends past the eye,
over the chin, or both. The genetics of overo and sabino are not yet fully
understood, but they can appear in the offspring of two solid-coloured parents,
whereas a tobiano must always have at least one tobiano parent.
Other animals The various types of magpie gave their
name to pied coloration. The bald eagle derives its name from the word "piebald"
in reference to the contrast of its white head and tail with dark body. The
term was used in The Conservationist by Nadine Gordimer when referring to
kingfishers. Many other animal species may also be
"pied" or piebald including, but not limited to, squirrels and birds. Snakes,
especially ball pythons and corn snakes, may also exhibit seemingly varying
patches of completely pigmentless scales along with patches of pigmented scales.
Some domesticated foxes born from the Russian Institute of Cytology and
Genetics also carry this coloring. Recently, a piebald blood python was
discovered in Sumatra. Bicolor cats carry the piebald gene. The
same pattern that applies to cats also applies to dogs when the white spotting
gene involved is indeed piebald and not another white-causing gene found in
dogs. The piebald gene is also found in domestic guinea pigs, goldfish, rabbits,
hamsters, goats, fancy rats, cows, and ferrets.
See also Pigmentation
Albinism Amelanism
Dyschromia Erythrism
Heterochromia iridum Leucism
Melanism Piebaldism
Vitiligo Xanthochromism
Horse Coat Equine coat color
Equine coat color genetics Pinto horse
Skewbald Tricoloured
References "Introduction to Coat Color Genetics"
from Veterinary Genetics Laboratory, School of Veterinary Medicine,
University of California, Davis. Web Site accessed January 12, 2008
External links "Piebald Moose". Ontario Out of Doors .
17 March 2012. Retrieved 15 December 2014.