Piebald

Key takeaways

Piebald belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Piebald to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Piebald from memory before moving on to harder problems.

Reference excerpt

A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots. The animal's skin under the white background is not pigmented. Location of the unpigmented spots is dependent on the migration of melanoblasts (primordial pigment cells) from the neural crest to paired bilateral locations in the skin of the early embryo. The resulting pattern appears symmetrical only if melanoblasts migrate to both locations of a pair and proliferate to the same degree in both locations. The appearance of symmetry can be obliterated if the proliferation of the melanocytes (pigment cells) within the developing spots is so great that the sizes of the spots increase to the point that some of the spots merge, leaving only small areas of the white background among the spots and at the tips of the extremities. Animals with this pattern may include birds, cats, cattle, dogs, foxes, horses, cetaceans, deer, pigs, and snakes. Some animals also exhibit colouration of the irises of the eye that match the surrounding skin (blue eyes for pink skin, brown for dark). 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 a white patch or spot. The reference is to the distinctive black-and-white plumage of the magpie. In medieval English pied indicated alternating contrasting colours making up the quarters of an item of costume or livery device in heraldry.

Horses

In British English piebald (black and white) and skewbald (white and any colour other than black) 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" and "buckskin pinto". 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.

Dogs In many dog breeds the Piebald gene is common. The white parts of the fur interrupt the pigmented coat patterns. Dogs that may have a spotted or multicolored coat, are often called piebald if their body is almost entirely white or another solid color with spotting and patches on the head and neck. The allele is called sP on the S-locus and is localized with the MITF gene. It is recessive, therefore homozygous individuals show this coat pattern, whereas the heterozygous carriers can be of solid color.

Other animals

Many other animal species may also be piebald including, but not limited to, birds and squirrels. A piebald Eastern gray squirrel named Pinto Bean gained prominence at the University of Illinois Urbana-Champaign after many students shared pictures and videos of him online. Snakes, especially ball pythons and corn snakes, may also exhibit seemingly varying patches of completely pigmentless scales along with patches of pigmented scales. In 2013, a piebald blood python was discovered in Sumatra. Some domesticated silver foxes born from the Russian Institute of Cytology and Genetics also carry this coloring. Bicolor cats carry the white spotting gene (incorrectly called 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 cows, ferrets, domestic goats, goldfish, guinea pigs, hamsters, rabbits, and fancy rats.

Holstein and Simmental breeds of cattle typically exhibit piebaldism.

Illustrations

Worked examples

Example 1 — a first encounter with Piebald

Start with the simplest possible case. Write down what Piebald claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Piebald before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Piebald ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Piebald

In research: Piebald appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Piebald in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Piebald is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal coat colors, Bird colours, Cat coat types, so understanding it makes those chapters shorter.
In everyday life: Look for Piebald outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Piebald in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Piebald means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Piebald out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Piebald in simple terms?

A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots.

Why does Piebald matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Piebald?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Piebald.