(Credit: Peter Maas / CC BY-SA 3.0.) Peter Maas via a Creative Commons license contiguous range is now highly fragmented. Plains zebra’s range in historic (red) and modern (green) times. “Because the spotted and partially spotted animals tend to be more frequent in areas that have been subject to habitat fragmentation, and in which the census sizes are low, we do, indeed, suspect that inbreeding (and genetic drift) contribute to the phenotype”, Professor Barsh replied in email. Inbreeding may increase the number of abnormally patterned wild zebrasĭoes inbreeding play a role in abnormally colored or patterned zebras? Tira’s melanocytes either lost their internal biological GPS or they have amnesia. “In other words, partial spotting in zebras is not an abnormality of melanin synthesis but instead is an abnormality of melanocyte identity.” “We think that in a partially spotted zebra like Tira, the melanocytes are still uniformly and ubiquitously distributed, however the melanocytes don’t know where they are on the body”, Professor Barsh elaborated. “If you shave a zebra, it is completely black”, Professor Barsh pointed out.
What we’re seeing in Tira is probably something different from a lack of melanocytes because melanocytes are uniformly and ubiquitously distributed throughout zebra skin. in August 2017, at the age of 19 years.) Is this coloration the result of too few melanocytes or production of abnormal melanin pigments? (Credit: John Schroedel / CC BY 2.0) John Schroedel via a Creative Commons license One such color variant that may be the result of normal numbers of melanocytes producing abnormal melanin pigments is the “blonde” or “golden” zebra, a faded-out white zebra that occasionally pops up in Kenya and Tanzania.Ī rare “Golden” or “Blonde” plains zebra living in captivity on Hawaii, named Zoe. “There are a variety of mutations that can disturb the process of melanin synthesis and in all of those disorders, the melanocytes are normally distributed but the melanin they make is abnormal”, Professor Barsh said. “In other animals where the biology and genetics are understood, ‘melanism’ refers to increased production of a specific pigment type”, Professor Barsh explained in email.Īre Tira’s black coloration and general lack of stripes the result of having too many melanocytes or are his melanocytes producing too much melanin? Melanins are synthesized by specialized cells known as melanocytes. “t is probably better described as ‘spotted’ or ‘partially spotted’.”īlack zebra stripes are created by melanins, a group of pigments that provide yellow, red, brown or black color to hair and skin. “This animal is different from most others that have been described as pseudo-melanistic”, Professor Barsh added. Professor Barsh is an expert on the genetic mechanisms that underlie differences in individual appearance, a specialty that provides important insights into basic biology as well as human disease.
“I do not know the origin of the term pseudo-melanism, but I think it is fair to say that is a popular and undefined term, used to refer to very rare animals that exhibit an apparent abnormality in the stripe pattern process such that light stripes are excluded from much of the trunk and back, but are more common on the extremities”, said geneticist Greg Barsh, a faculty investigator at the HudsonAlpha Institute for Biotechnology and a Professor Emeritus at Stanford University. (Credit: Frank Liu / Frank Liu Photography, with kind permission.) Frank Liu The zebra, named Tira, gets it peculiar markings from a rare pigment disorder. Newborn black zebra foal with white polka-dots (and a few partial stripes) spotted in Maasai Mara.
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