Tracing the genetic origin of mane growth in domestic horses: an innovative model to identify genetic factors that regulate hair growth

Last changed: 26 June 2018

Knowledge of which genetic factors regulating hair growth is limited. Within this project we will take advantage of the remarkable phenotypic variation among horses to search their entire genome for mutations that regulate hair growth.

The mane of the domestic horse grows as human head hair practically indefinitely. Extant wild equid species (Equus ferus) and other closely related species of the Equidae family have a short upright mane. The origin and biological function of the horse mane is unknown. We hypothesize that the origin of the horse mane is the result of artificial selection of hair growth mutants by people during domestication; therefore, the aim of this project is to identify these mutations.

Horses provide an innovative model for mapping hair growth mutations as they display an extraordinary variation in this trait as well as have a favourable population structure for gene mapping experiments. Another major advantage of using the horse as a model for mapping growing hair is that there are other related species of the Equidae family that carry the original genetic variant (ancestral haplotype) to compare with. These are three species of zebra, wild donkeys and the Przewalski's horse, all of which have a short upright man.

We are planning to use Icelandic horses in a genome scan for gene discovery. Andalusian horses and Tinker horses will be analysed to validate the results. These breeds are well known for variation in length and thickness of the mane. Zebra, wild donkeys and the Przewalski's horse will be analysed to compare with the original genetic variant.

The information from the study will provide valuable knowledge about the origin of the mane in horses and genes that regulate hair growth. This information can be helpful in different disorders of hair loss in other animals and humans.

Project blog - News

May 27-June 6, 2018

Study visit and sampling in Iceland

We can see the great variation in length of both forelock and mane in Icelandic horses

In Iceland we visited breeders and the breeding show in Selfoss and Sprettur. We also met our international collaborators Elsa Albertsdóttir and Þorvaldur Kristjánsson. They informed us about the breeding history and how mane and tail and other traits are assessed at the breeding field tests. 

We sampled and measured many Icelandic horses

We are very grateful to all breeders and horse owners in both Sweden and Iceland for letting us measure mane and tail in your horses. Also thank you all horse owners that have sent hair samples from your horses. You can still send us samples, we are especially looking for more stallions or geldings with the short type of forelock as well as mares with long forelock! The first results of the genomic scan in Icelandic horses will be presented later this year or in the beginning of next year.

February-June 2018

We have continued to sample and measure Icelandic horses in Sweden and Iceland

We have visited trainers and breeders in Sweden. We have been to the breeding show in Romme and will also visit the breeding show in Axevalla.

One stallion with very long mane and forelock that we measured is Viking från Berget

January 2018

Sample collection and direct measurements on mane and tail in Icelandic horses

We are looking for more Icelandic horses that we can measure. The horses should have individual scores on mane and tail from breeding evaluation and we search for the extremes, horses with low points (5-6.5) or high points (9-10). In stallions we also include 7.0 as a low point and in mares 8.5 as a high point because the point distribution is different in stallions and mares. Please contact us if you have a horse that we can measure. E-mail:

November 19-25, 2017

Sample collection from Andalusian horses in Spain

Sample collection and direct measurements of mane and tail in Andalusian horses.

We also sampled donkeys which will be analysed to compare with the original (ancestral) genetic variant.

Donkeys all display short, stiff and upright manes and they carry the original (ancestral) genetic variant.

November 17, 2017

Semi-annual project meeting at Estación Biológica de Doñana (CSIC) Sevilla in Spain

September 2017

Sample collection and evaluation of estimated breeding values (EBVs) and points for mane and tail in Icelandic horses

August 19, 2017

Sample collection started

Sampling at the breeding evaluation and the national show for Tinker horses in Björklinge Sweden.

June 19-21, 2017

Semi-annual project meeting at SLU Uppsala, Sweden

We evaluated the protocol for mane and tail measurements. A little Shetland pony acted as a test horse.

Many want to participate in the project….

March 22-25, 2017

Kick-off meeting for the project at Estación Biológica de Doñana (CSIC) Sevilla in Spain


The project is conducted in close collaboration with professor Juan José Negro Balmaseda and his research team at The Doñana Biological Station in Spain.

The project is funded by the Swedish Research Council and runs for four years starting in 2017.