Hi,
I am new to this forum. Sorry for re-awaking a two-year-old thread, but I'd like to clarify some things regarding the breeding back the aurochs.
First of all, let's have a look at heck cattle, and then what TaurOs Project does.
Heck cattle not only is genetically very different from the aurochs (what is very likely considering the origin of the breed), its phenotype also differs very much. That means, it not even looks like the aurochs. It has the typically bulky trunk of domestic cattle, short legs, flabby musculature, a small and short head, large udders and is much too small, little sexual dimorphism etc. It's body resembles the aurochs in no way. Also, the horns are too upright, to thin and the curvature is different. However, there are some similarities with the aurochs concerning the fur colour, but there are cattle breeds which are more authentic regarding that aspect. Therefore, heck cattle is not very close to the aurochs; spanish fighting bulls and other iberian cattle are much closer, for example. Some say heck cattle was the biggest zoological hoax in the 20th Century, and I think this is partly true.
Furthermore, the ecological capacity of heck cattle likely is somewhat restricted. They are suited to central europe, but likely wouldn't survive in Iberia or the Hungarian steppe, and only survive in the netherlands with high mortality rates.
For an accurate replacement of the aurochs in the wilderness, an accurate type of bovine is needed that is as aurochs-like as possible.
TaurOs Project is a scientific breeding-back project, considering aspects which were neglected previously, such as the ecological capacities, phenotypical accurateness and genotypical closeness in the breeds which were studied and now are part of the project. TaurOs Project looks for hardy cattle which is suited to local natural circumstances, which are totally different in f.e. Iberia from eastern Europe. They try to find the most aurochs-like cattle that are available, such as primitive Sayaguesa, Maronesa, Pajuna, Podolica etc. which fit the purpose. Also, the genetic map should control the aurochs-likeness on a deeper level, apart from the ecological and phenotypical suitability.
The most aurochs-like cattle are crossed and selected for aurochs-features, and after some generations, a breed that resembles the aurochs in appearance, ecology and hopefully also genetics, will be established. These cattle will be released in natural reserves in order to live a natural life without human interference and function like the aurochs some centuries ago. They have some splendid crossbred individuals already, therefore I think they will reach their goals with the new techniques and scientific preparation. Don't forget, heck cattle was breed almost hundred years ago, we have much better possibilities and a much deeper knowledge now.
Regarding cloning; of course, cloned aurochs would be the best option. But it is very difficult to get a complete genome only from ancient bones, and if it is managed in single individuals, enough diversity is needed to build a viable population from that. Maybe this won't ever be achieved, but if single individuals are managed to be cloned, it would be possible to incorporate them into the TaurOs-ochs to save as much from the original material as possible.
I hope this was helpful,
Cheers!