Saturday, 21 August 2021

A Pleistocene wild horse from Denmark

A few years ago, I did a life restoration of this wild horse skeleton from Denmark. But it wasn't that good, I found. So I did a new one, and finally had the time to finish it: 
In order to be as precise as possible, I tracked the original horse skeletons out using a pencil and paper. For the reconstruction of the horse, I used genetic information and the horse depictions from the Ekain cave. Genetic information tells us that most Pleistocene wild horses had the bay allele A+ [1], and both the dun allele and the wildtype non-dun (nondun1) allele was present in the population [2]. The horse therefore was either bay or bay dun. I chose bay dun, because it probably was more common as non-dun is recessive. The horse depictions at Ekain tell us that the striping was pretty pronounced, more so than in extant Przewalski's horses and domestic horses. The mane of all Pleistocene wild horses was erect. All in all, the Pleistocene wild horse was rather similar to the Przewalski's horse in appearance, although the head not quite as large, apparently. 
Horses like this one probably were the ancestors of Holocene European wild horses, according to a 2019 study [3]. They their colour shifted from mostly bay dun to mostly black (or maybe additionally black dun) during the Holocene [2]. For a reconstruction of the Holocene wild horse, go here

Literature

[1] Ludwig et al.: Coat color variation at the beginning of horse domestication2009.
[2] Sandoval-Castellanos et al.: Coat colour adaption of post-glacial horses to increasing forest vegetation. 2017
[3] Fages et al.: Tracking five millennia of horse managment with extensive ancient genome time series. 2019. 

6 comments:

  1. A very nice life restoration Daniel.

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  2. It kinda looks like a Quagga that has lost the stripes of the front half of its body.

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  3. In the Ekain cave horses are depicted as black/grey as well as brown/yellowish (not sure whether colors have faded much). Maybe black and brown horses were contemporary with eachother and there were mixed herds or herds that leaned more between one or the other but moved migrated between different areas but that migratory routes overlapped in certain areas (hence cave artists being familiar with and painting both types and painting them in one mural).
    Maybe there was never just one type of European horse? Present day animals have subspecies, why are some prehistoric animals treated as monoliths?

    https://fr.wikipedia.org/wiki/Grotte_d%27Ekain

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    1. Dun and nondun wild horses existed side by side, both in the Pleistocene and in the Holocene. The black allele and the bay allele did so as well after 16.000 years BP, but the black allele was originally restricted to the Iberian peninsular and spread from there subsequently. Summa summarum, wild horses of different colours existed side by side in Europe. I wrote that in nearly all of my posts on wild horses.

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  4. You wrote: "I chose bay dun, because it probably was more common as non-dun is recessive." Recessive doesn't mean that an allele or a phenotype is less numerous in a population. Do you mean recessive in the Mendelian sense or do you mean less frequent in the Hardy-Weinberg sense? This wasn't clear. Dominant phenotypes can exist in populations at low frequencies with the recessive phenotype predominating numerically.

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    1. Yes, dominant/recessive doesn't say much about the frequency of the respective phenotypes alone. But when most individuals are heterozygous because the alleles are evenly distributed, then the recessive phenotype is much less common than the dominant one. That was the case I was assuming for the Pleistocene wild horse.

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