December 14, 2017

Article Navigation MLPH Genotype—Melanin Phenotype Correlation in Dilute Dogs

The researchers of this article conducted research concerning the dilution of the color of a dog’s coat. The gene for dilution has been linked to hair loss in several dog breeds, including the Weimaraner; the gene for dilution is also recessive, meaning a dog must receive a the gene from both of its parents in order to have a diluted coat. When a Weimaraner inherits the trait for discoloration, the dog’s genes prevent it from producing proteins in the dogs coat that allow for proper pigmentation. Symptoms of color dilution alopecia (CDA) include lighter shades in areas typically darker on the dorsal side of the dog as well, hair loss, and legions that worsen as the dog ages. The signs of CDA develop anywhere between the ages of three and twelve months.

In order to test for the gene causing the dilution, the researchers observed DNA from blood samples taken from 935 purebred individuals of various breeds. Skin biopsies of samples taken from the hair follicles of 45 dogs were analyzed as well. Polymerase chain reaction (PCR) was used to obtain larger quantities of the DNA. Additionally, the researchers looked at the tissue collected from the hair follicles under a microscope to notice any physical differences.

The authors of the study ultimately concluded that the gene for color dilution was from a mutation that occurred some point in the evolution of the dogs. The mutation resulted in the clumping of melanin on the epidermis. Because the melanin was not spread throughout the epidermis, certain areas of the epidermis lacked the compound, making it appear that the dogs have lighter shades of color in those areas.

M. Welle, U. Philipp, S. Rüfenacht, P. Roosje, M. Scharfenstein, E. Schütz, B. Brenig, M. Linek, L. Mecklenburg, P. Grest, M. Drögemüller, B. Haase, T. Leeb, and C. Drögemüller. “MLPH Genotype—Melanin Phenotype Correlation in Dilute Dogs.” Journal of Hereditary: 23 March 2009. Web.

Original Article: https://academic.oup.com/jhered/article/100/suppl_1/S75/886518

Summary by Ford Young