{"id":67,"date":"2020-01-30T16:52:07","date_gmt":"2020-01-30T16:52:07","guid":{"rendered":"http:\/\/blogs.dickinson.edu\/writingsciencenews2020\/?p=67"},"modified":"2020-04-29T21:36:34","modified_gmt":"2020-04-29T21:36:34","slug":"the-new-genetic-explanation-for-canine-color-con","status":"publish","type":"post","link":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/2020\/01\/30\/the-new-genetic-explanation-for-canine-color-con\/","title":{"rendered":"The New Genetic Explanation for Canine Color Concentration"},"content":{"rendered":"

The earliest record of color variation in dogs is from 10,000 year old arch<\/span>eological evidence. N<\/span>ow, finally, the intensity of this variation has been explained genetically due to the work of researchers at the University of California-Davis. In this research, the use of genome-<\/span>wide\u00a0<\/span>association\u00a0<\/span>was used for specific dogs to determine<\/span>\u00a0the number of copies<\/span>\u00a0of a copy number variant (<\/span>CNV<\/span><\/i>)<\/span>, which is a repeating section of the genome, present in their DNA. A genome-wide association study involves rapidly scanning a genome to find areas where there is genetic variation. By using this method, the researchers discovered a genetic region that controls color intensity in a number of dog breeds.<\/span><\/p>\n

\n

They found that a CNV in the <\/span>KITLG\u00a0gene<\/span> on chromosome 15 controls color intensity in dogs<\/span>. The higher the number of copies of this CNV, the more intense the color of the dog’s coat.\u00a0<\/span><\/em><\/h4>\n<\/blockquote>\n

Pigmentation in dogs<\/span>\u00a0can come<\/span> from the chemicals <\/span>pheomelanin<\/span>\u00a0(yell<\/span>ow) and eumelanin (black). On<\/span>e gene that has been found to control the variation of these pigments <\/span>in dogs is the\u00a0<\/span>KITLG<\/span><\/i>\u00a0gene. To evaluate the genetic basis for light and dark red\u00a0<\/span>phenomelanin<\/span>, the UC-Davis researchers conducted a genome-wide association study in 35 Nova Scotia Duck Tolling Retrievers<\/span>. These dogs<\/span>\u00a0were classifi<\/span>ed as light (n=23) or<\/span>\u00a0dark (<\/span>n=<\/span>13).<\/span>\u00a0<\/span><\/p>\n

Blood and saliva were collected from these dogs through the UC-Davis Veterinary Medical Teaching Hospital. To compare the CNV<\/em>s in the genetic data from different Nova Scotia Retrievers, the researchers used the PCR method, where DNA is broken down into pieces and and then multiplied to attain a number of copies of a specified portion of the DNA. Next, they performed the genome-wide association study across the KITLG<\/em> gene and then compared the number of CNV<\/em>s.\u00a0<\/span>The results showed that dark red hair Nova Scotia Retrievers <\/span>had significantly more\u00a0<\/span>CNV<\/span><\/i>\u00a0copies compared to light red hair Retrievers.\u00a0<\/span><\/p>\n

\"\"

Image from malp007 via Flickr. A Nova Scotia Retriever training with a wooden duck.
These dogs were originally known as the little river duck dog. They have webbed feet and a double coat so they are well adapted to water and so they have been used for waterfowl hunting for two centuries.<\/p><\/div>\n

These comparisons were repeated in multiple different breeds such as light grey breeds like the Bearded Collies and Old English Shepherds, and also in black breeds like Rottweilers and Black Coated Retrievers. The results showed that there was a correlation between high <\/span>CNV<\/span><\/i>\u00a0copy numbers and dog hair color intensity.\u00a0<\/span>\u00a0<\/span><\/p>\n

This correlation was not found in Poodles, a breed with longer hair. Analysis along<\/span>\u00a0the hair shaft showed that<\/span> Poodles with high<\/span>er<\/span>\u00a0<\/span>CNV<\/span><\/i>\u00a0copy number<\/span>s had more uniform color intensity and a hi<\/span>gher average hair color intensity along <\/span>the length of their hairs . <\/span>Poodles with lower\u00a0<\/span>CNV<\/span><\/i> copy numbers had less color intensity in the roots of their hairs, more color intensity at the tips,\u00a0 and less overall color intensity. This led to the hypothesis that higher <\/span>CNV<\/span><\/i> copy numbers lead to a more uniform <\/span>color intensity\u00a0<\/span>and<\/span>\u00a0a<\/span> higher average color intensity.<\/span>\u00a0<\/span><\/p>\n

Prior to these discoveries, the understanding of pigmentation in dogs was that it was controlled through the pigment\u00a0<\/span>switching genes <\/span>MC1R<\/span><\/i> and <\/span>ASIP<\/span><\/i>. The alteration of\u00a0<\/span>MC1R<\/span><\/i>\u00a0and\u00a0<\/span>ASIP<\/span><\/i>\u00a0leads to the different variations in color. For example, the appearance of solid red\/ yellow means that there is a loss of function of\u00a0<\/span>MC1R<\/span><\/i>\u00a0which results in the sole production of\u00a0<\/span>pheomelanin<\/span>.\u00a0<\/span>\u00a0<\/span><\/p>\n

In this new study, by comparing genetic data, the researchers have demonstrated that the CNV<\/em> in the KITLG<\/em> gene is a newly discovered portion of DNA that controls the intensity of eumelanin and pheomelanin intensity in a number of dog breeds with a spectrum of coat colors<\/span>. However<\/span>, there are some breeds where this correlation has been <\/span>found to be inconclusive; namely in Golden Retrievers<\/span> and Labrador Retrievers, where t<\/span>here is no significance in\u00a0<\/span>CNV<\/span><\/i>\u00a0copy numbers.\u00a0<\/span>Due to large scale artificial breeding practices focused on varying coat colors in dogs, it is not a surprise that there are many different regions of DNA that affect pigmentation in dogs. This would explain why the results seen in these two Retriever breeds are inconclusive as there might be a different DNA region that controls their color.\u00a0<\/span><\/p>\n

\u00a0<\/span><\/p>\n

Weich<\/span>, K.,\u00a0<\/span>Affolter<\/span>, V., York, D.,\u00a0<\/span>Rebhun<\/span>, R.,\u00a0<\/span>Grahn<\/span>, R.,\u00a0<\/span>Kallenberg<\/span>, A., and\u00a0<\/span>Bannasch<\/span>, D. 2020. Pigment Intensity in Dogs is Associated with a\u00a0<\/span>Copu<\/span>\u00a0Number Variant Upstream of KITLG.\u00a0<\/span>Genes\u00a0<\/span><\/i>11(1): 75.\u00a0<\/span>\u00a0<\/span><\/p>\n

For more information, go to: \u00a0https:\/\/www.mdpi.com\/2073-4425\/11\/1\/75<\/span><\/a>.\u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

The earliest record of color variation in dogs is from 10,000 year old archeological evidence. Now, finally, the intensity of this variation has been explained genetically due to…<\/p>\n","protected":false},"author":4278,"featured_media":85,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[2147,2085],"class_list":["post-67","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-dogs","tag-genetics"],"_links":{"self":[{"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/posts\/67","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/users\/4278"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/comments?post=67"}],"version-history":[{"count":0,"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/posts\/67\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/media\/85"}],"wp:attachment":[{"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/media?parent=67"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/categories?post=67"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.dickinson.edu\/writingsciencenews2020\/wp-json\/wp\/v2\/tags?post=67"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}