Mutations cause horses to change color to gray and white from a young age

The image of a white horse is a symbol of a great influence in human culture throughout the world.

An international research group led by Uppsala University researchers recently discovered mutations that cause strange characteristics in horses. They also demonstrated that white horses carry the same two allele mutation that originated from a common ancestor thousands of years ago.

This study is particularly appealing to other medical studies because the mutation that makes white animals also increases the risk of melanoma.

Most white horses carry dominant mutations that make them turn gray quickly and grow. Gray horses were born in color (probably black, brown or chestnut), but the process of 'graying' began very early in the first year of their life. They are usually completely white when they are 6 to 8 years old but their skin remains pigmented. Thus this process is similar to the graying process in humans but takes place at a very fast rate for horses carrying mutant genes. Research has proven that all gray horses carry the same mutation. That kind of mutation must certainly be inherited from a common ancestor that lived about thousands of years ago.

Leif Andersson - the only researcher - said: 'This is fascinating. In the past when a horse was born changed color to gray, then gradually turned white. The man who observed this he was very interested in its beautiful appearance and used the white horse to breed. Thanks to that, new mutations are transmitted from generation to generation. ' Today, about 1 in 10 horses have mutated gray according to age.

A high-contrast picture captures the white Andalusian stallion in the sun contrasting with the black background.(Photo: iStockphoto / Baldur Tryggvason)

It is clear that people all over the world have greatly appreciated white horses. The main demonstration is a huge collection of stories and paintings depicting white horses. In a recent article, the admiration for the beauty of white horses was illustrated by the late 17th century painting by Swedish king Karl XI about his white horse, Brilliant.

Gray horses are particularly interesting in terms of medicine because the kind of mutations they bring leads to the development of melanoma. About 75% of gray horses over 15 years of age have mild melanoma . Some cases even develop malignant melanoma. Therefore, the new study also sheds light on the molecular mechanism that makes tumors.

Leif Andersson said: 'We believe that the gray mutation stimulates the development of melanocytes. This led to the loss of melanocytic stem cells before the maturity, but they were necessary to produce pigmentation while gray mutation facilitated the expansion of some melanocytes cause skin pigmentation '.

Domesticated animals are excellent models for the development of biodiversity, as Charles Darwin realized. White horses are an excellent illustration of the importance of mutations as a key hidden mechanism for phenotypic diversity in species and between species. Gray mutation does not alter any protein structure but it does affect the genetic activity of two genes. The researchers found that white horses carry a redundant copy of DNA on one of the two genes.

Leif Andersson concluded: 'It seems that the operating mutation as the kind of mutation we discovered in white horses contributed to the dominant group of mutations that explain the difference between domesticated and species-like animals. like humans and chimpanzees' . The study is published in the July 20 issue of the journal Nature Genetics.