The Emperor Has No Stripes: retrieving the phenotype of the quagga will need some uncomfortable realism

The quagga (Equus quagga quagga, https://en.wikipedia.org/wiki/Quagga) is the extinct southernmost subspecies of the plains zebra.

It differs from the adjacent, surviving subspecies (Equus quagga burchellii) in having reduced striping on the body, a predominantly dark tone on the head, neck and torso, and a short forelock (https://www.newdinosaurs.com/wp-content/uploads/2016/11/1123_quagga_ilvy.jpg and https://en.wikipedia.org/wiki/Quagga#/media/File:Quagga_photo.jpg and https://www.oceansbridge.com/shop/artists/a/agasse-jacques-laurent/quagga and http://messybeast.com/extinct/quagga.htm).

Several decades ago, selective breeding was started with the goal of retrieving the phenotype of the quagga from a carefully-chosen, minimally-striped founder stock of Equus quagga burchellii (https://www.quaggaproject.org/ and https://blog.nature.org/science/2014/10/13/quagga-can-an-extinct-animal-be-bred-back-into-existence/ and https://nuwejaars.com/freddy-and-his-rau-quagga-family-a-qa-on-this-innovative-project/).

Although the project continues, a spectacular result has already been achieved after five generations: an unprecedentedly pale phenotype (https://www.sciencephoto.com/media/388824/view/quagga-like-zebra and https://www.facebook.com/quaggaproject/photos/a.2587827881513693/2617271545235993/?type=3 and https://www.zmescience.com/medicine/genetic/quagga-recreated-01022016/).

This interim result resembles the extinct quagga in only one way: the minimal striping on the legs, torso, shoulders and haunches. The forelock and the rest of the mane remain as long as in Equus quagga burchellii, and in the case of the overall tone of the head, mane, neck, and torso there is regress instead of progress, because the interim result is paler than in E. q. burchellii and therefore far paler than in the extinct quagga.

Overall, this is a case of one step forwards, one step back.

Despite the incongruous pallor of the interim result, the project has been hailed as already successful from all sides (e.g. https://www.farmersweekly.co.za/conservation-agriculture/quagga-rebreeding-a-success-story/).

The celebration seen in all the commentary on this topic is premature and indicates a level of cognitive dissonance which is now the main problem for the project.

In order to correct course, the breeding will in future have to select for darkness on the head, neck and torso (https://www.extinctanimals.org/wp-content/uploads/2015/07/Quagga-Zebra.jpg). However, it is difficult to envisage how this can be done without 'going backwards', i.e. without inadvertently undoing the hard-won reduction in striping.

The particular challenge: the more that selection has reduced the striping, the more it has also produced an overall depigmentation. So far, it seems that if one starts with Equus quagga burchellii and breeds selectively, one cannot reduce the striping without also precluding the necessary darkening of the ground-colour between the stripes on the torso, and the necessary widening of the dark stripes on the neck and mane. Please note that the problem of darkening consists of two components at apparent odds with each other.

Hence the real - but largely unacknowledged - disappointment at this stage: whereas the extinct quagga was (except for the conspicuously whitish fore legs) the darkest of all species/subspecies of zebras, the interim result is by far the palest of all zebras.

Because this interim result is in an important way the opposite of the one desired, no amount of satisfaction with the minimisation of the striping will ultimately be able to sweep the problem under the hide, as it were.

The Quagga Revival Project may yet surprise us with some way of keeping the striping minimal while a) darkening the ground-colour on the torso, and simultaneously b) widening, on the neck and mane, the dark stripes to the point of switching the effect to pale striping on a dark ground-colour (see https://thecuriouschameleon.files.wordpress.com/2012/09/800px-quagga_side.jpg and https://en.wikipedia.org/wiki/Quagga#/media/File:Berlin_Quagga.jpg). And it may eventually focus on the problem of the forelock.

However, the deliberate course-correction needed for this will certainly be challenging. Does the project have the leadership, enthusiasm and funding to overcome a 'reality check' of this gravity?

הועלה ב-ספטמבר 7, 2021 10:29 לפנה"צ על ידי milewski milewski

תגובות

The following individual is representative of the founder stock chosen, in about 1987, for what has become the Quagga Revival Project: https://www.inaturalist.org/observations/47358742. In hindsight, it seems that it might have been better to choose individuals like https://www.inaturalist.org/observations/17749946, which were also available. It is somewhat ironic that the latter individual, occurring naturally in Equus quagga burchelli, resembles the extinct quagga more closely in overall darkness than does the result of selective breeding over five generations.

פורסם על-ידי milewski לפני יותר מ 2 שנים

The following is about the darkest overall colouration so far produced by the selective breeding, but this photo seems to have been taken soon after the animal dust-bathed: https://www.inaturalist.org/observations/33295575.

פורסם על-ידי milewski לפני יותר מ 2 שנים

The following is a particularly clear photo of one of the approximately 20 mounted specimens of the extinct quagga. Bear in mind that, after one and a half centuries, this fur has faded considerably: https://fineartamerica.com/featured/quagga-natural-history-museum-londonscience-photo-library.html.

פורסם על-ידי milewski לפני יותר מ 2 שנים

The following shows the length of the mane, including the forelock, in Equus quagga burchellii: https://www.mindenpictures.com/stock-photo-burchell-s-zebra-equus-quagga-burchellii-adult-close-up-of-head-pumba-naturephotography-image80173613.html. Please compare this with the short mane and forelock of the extinct Equus quagga quagga: https://www.flickr.com/photos/randomrupert/6770292831/.

פורסם על-ידי milewski לפני יותר מ 2 שנים

Perhaps if one could take the DNA of a preserved specimen and use it to clone a new individual, this discrepancy of the coat colour could be corrected for, with the cloned individual being bred with the project's zebras (after successfully reaching maturity) to achieve the vision of the project.

פורסם על-ידי dinofelis לפני יותר מ 2 שנים

@dinofelis Hi Warren, Many thanks for your comment, with regards from Antoni.

פורסם על-ידי milewski לפני יותר מ 2 שנים

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