Here is the video.
"Breeding-back" aims to restore or immitate extinct animals by selective breeding. This blog provides general information, the facts behind myths and news from various projects.
Monday, 30 November 2020
Some Lidia bulls with long legs
Here is the video.
Sunday, 29 November 2020
Auerrind project update
So that we can expect the following crosses for the next few years:
Apollo (Watussi x Maremmana) © Claus Kropp |
Benito (Maremmana x Sayaguesa) © Claus Kropp |
Wednesday, 25 November 2020
How to limit undesired traits in "breeding-back"?
Therefore, I have been making some thoughts on a project that minimizes the amount of undesired traits but still is able to achieve all the aurochs traits that are achievable with domestic cattle.
Such a project would have to chose breeds that already resemble the aurochs to a large degree and do not have any undesired recessive colour variants or different horn shapes or sizes. I think that a combination of wildtype-coloured Lidia, Maronesa and Sayaguesa would be suitable for this purpose. Lidia would contribute a very aurochs-like body morphology, Maronesa has the sexual dimorphism and horn shape (in good individuals) and Sayaguesa would contribute large size, long snouts (at least in cows) and long legs. The horn shape of this combination would be good to very good, no deviant colour variants would be present and since some Sayaguesa grow up to 170 cm withers height the right size would also be found in the gene pool. The bulls might end up a bit short-legged, however, and the horn size might not be that impressive, but overall it would be possible to breed a good result quite fast and would be a lot easier to stabilize. I would love to see Lidia x Maronesa, Lidia x Sayaguesa or Sayaguesa x (Lidia x Maronesa).
Monday, 23 November 2020
The genes influencing horn size
While the genetics of coat colour of domestic animals are comparably well-studied, the genetic background of other aspects, such as the horn shape and size of cattle, remains nebulous. Only the genes for the polled and scurred conditions are resolved, while the genes that determinate the shape of the horns as well as the size are unresolved.
Horn size is a quantitative trait. That means it is influenced by a larger quantity of genes and shows a continuum. The identity and influence of those individual genes is probably largely unknown, but crossbreeding results can provide a clue for speculations.
The idea for this post came to my mind when I saw photos of the Taurus cow “Lippe”, which is an F2 (Sayaguesa x Heck) individual.
F2 Heck x Sayaguesa cow Lippe in the Lippeaue © Matthias Scharf
It is notable that the cow has very small horns like a Chianina. Yet it has no Chianina in its ancestry, only Heck and Sayaguesa. Two breeds that have horns that can be described as at least medium sized – the horns of the Heck cattle used in the Lippeaue are actually comparably large. So it is possible to breed individuals with tiny horns from two breeds that have at least medium-sized horns within only two generations.
How is that possible? One possibility is that the gene or genes for this tiny horn size is or are recessive, and that the F2 carries two of the recessive alleles and is thus homozygous. However, in this case we would also see tiny-horned Sayaguesa and Heck cattle on occasion. The other explanation, which is much more plausible to me, is that this tiny horn size is the result of a cumulative effect. Sayaguesa may have alleles for small horn size one the one locus, and Heck cattle on another locus. In the F1 generation these loci would be heterozygous, thus the horn size would still be medium-sized. But in the F2 generation, coincidentally, the cow might be homozygous for the alleles causing small horn size on both loci, resulting in the very small horns not seen in the parental breeds or F1 animals. It might involve even more loci, two would be the minimum.
The horn size we see in Chianina might be caused by different loci or alleles, we cannot know without resolving the alleles and testing it. Crossbreeds suggest that at least some of the alleles causing the small horn size in Chianina are recessive. The crossbred Taurus bull 01 856 was the son of the bull Laokoon and the cow Larissa, two individuals with medium-sized horns. However, both parents were part Chianina (25% respectively 62,5%). 01 856 happened to have rather small horns, not larger than in Chianina. This suggests that at least some of the alleles causing the horn size in Chianina are recessive. It would also explain why many half-Chianina individuals had horns of medium size (such as the bull Luca or the cow Larissa).
If the small horn size of Chianina is indeed recessive, this is bad news. Recessive alleles are difficult to purge effectively from the population.
If it is possible to breed horns smaller than in both parental breeds within two generations, as the cow Lippe demonstrates, it might also be possible to breed large horns out of two breeds with medium-sized horns in few generations. This would depend on which alleles the parental breeds have.
Friday, 20 November 2020
The Prejlerup aurochs
Thursday, 19 November 2020
Ancient Europe's landscape: grassland savannah or forest?
The traditional view is that of Europe being a heavily forested continent. This view has been challenged in recent decades. It has been proposed that herbivores prevent open landscapes from becoming forested by damaging forest growth with their feeding, and are even able to turn forests into open landscapes this way. As a result, Europe’s original landscape would not have been one big forest but a mix of open landscapes, park-like landscapes and forests [1]. Some even claim Europe was a large grassland savannah.
Indeed no large mammal in Europe is dependent on forests while they need at least some open landscape in their habitat [2,3]. Africa is used as an analogue, where large herbivores are claimed to create the open landscape we are familiar with. Especially elephants, which uproot trees are suspected to create open landscapes [3].
There is conflicting data, however. Studies suggest that the uprooting of trees by elephants does not diminish the forest but instead speeds up the forest rejuvenation [4]. And it is overlooked that not only the savannah but also the deep rainforests are home to large herbivores, such as the forest elephant (Loxodonta cyclotis), the forest buffalo (Syncerus nanus) and the okapi (Okapia johnstoni) [4]. There are also several species of large herbivores living in the rain forests of South-East Asia (banteng, gaur, Asian elephant). If large herbivores create open landscapes, elephants in particular, the forest elephant would be a contradiction in itself: a forest-adapted elephant (f.e. the smaller size) would not exist if elephants created open landscapes with their feeding and uprooting of trees.
Furthermore, and more importantly, palynologic data suggests that Europe was densely forested until very recent millennia when man started agriculture in Europe [4]. Also the insect fauna shows that forest-dwelling species were very common in Europe until recently [4]. It is argued, however, that also an intensely grazed grassland area has the same palynologic signature as a closed forest (see for example the works of Frans Vera). But this apparently is only the case at a very high herbivore density [4], and it cannot explain why the data from insects suggest high forestation.
Another argument against ancient Europe being a grassland savannah and for a strongly forested continent is the distribution of the European wild horse in the Holocene. The horse is heavily dependent on a grassy diet and is an open land animal. It got very rare in Europe after the last glacial [5]. It virtually disappeared from Central Europe [5]. When agriculture began, the equine remains increased again, possibly due to an increase in open landscapes [5]. These distribution patterns contradict the hypothesis that Europe would have been a grassland savannah due to grazing and instead supports the hypothesis of Europe without human influence being a mostly forested continent.
Europe’s original landscape continues to be a subject of debate. The data that is available to me suggests that the idea of ancient Europe being a grassland savannah with large herds of horses is not the likeliest scenario.
Literature
[1] Bunzel-Drüke et al.: Der Einfluss von Großherbivoren auf die Naturlandschaft Mitteleuropas. 2001.
[2] Beutler: Die Großtierfauna Europas und ihr Einfluss auf Vegetation und Landschaft. 1996.
[3] Bunzel-Drüke et al.: Überlegungen zu Wald, Mensch und Megafauna. 1994.
[4] van Vuure: Retracing the aurochs – history, morphology and ecology of an extinct wild ox. 2005.
[5] Sommer et al.: Holocene survival of the wild horse in Europe – a matter of open landscape? 2010.
Friday, 13 November 2020
Life reconstruction of the Vig aurochs
The Vig specimen at the National museum of Denmark, © Markus Bühler |
Life reconstruction of the Vig bull |