Category: Domestication

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Feral livestock: pest or useful resource?

I ((Contributed by Michael Kubisch)) came across an interesting article while browsing through my archives. ((Dirk van Vuren and Philip W. Hedrick. Genetic Conservation in Feral Populations of Livestock. Conservation Biology, Vol. 3, No. 3. (Sep., 1989), pp. 312-317.)) It is by now quite dated, but with global climate changes upon us, I think it may actually be more relevant now than it was 20 years ago. The article makes a case for the preservation of feral livestock which are descendents of animals that, once kept by humans, either manage to escape into the wild or are simply abandoned when no longer useful.

Not all species do this equally well. Sheep have a hard time managing on their own, while pigs, on the other hand, easily adapt to all sorts of environments. In the US there are an estimated 4 million feral pigs, many of which may be descendents of pigs brought over by the Spanish in the 16th century. Similarly successful have been feral horses in the US and camels in Australia, the latter being so abundant that there are efforts underway to use them for meat production.

The article makes the case for preserving feral livestock as a valuable genetic resource because the adaptation to life in the wild may have favored or preserved traits, for example resistance to specific parasites or a higher temperature tolerance, that domestic livestock may have lost.

Of course, there are drawbacks: in some countries feral animals are considered pests and there is no doubt that particularly pigs can and do inflict serious damage on the environment. And because of this there are often programs in place to eradicate or at least control feral populations, although such attempts have not always been all that successful. At any rate, in an age of changing climate conditions it might perhaps be more worthwhile to keep some feral livestock around than to try to get rid of it. 

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Orchid to be exploited

Remember the recent post about ylang ylang? Timbuktu Chronicles sent me to an oldish article from South Africa’s Mail & Guardian which lists the tree among Madagascar’s fragrant exports. But the article is really about a rare and threatened Malagasy orchid and how it will be cultivated for the French perfume industry. I hope everyone has their ABS arrangements down tight.

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Is the kouprey a species?

The kouprey is a very elusive wild bovid that is said to roam the Southeast Asian jungle. It was only discovered by outsiders at the beginning of the last century, but it has seldom been seen since and there are concerns that it may, in fact, already be extinct. (It is currently listed on the IUCN Red List of Endangered Species). As if that wasn’t bad enough, there is now a vigorous debate about whether the kouprey is — or was — in fact, a separate species at all, or merely some type of feral hybrid.

A report published some months ago in the Journal of Zoology showed that a comparison of mitochondrial DNA obtained from several banteng revealed some homology — similarity — with a previously published DNA sequence from a kouprey. ((Galbreath et al., 2006. J. Zool. 270:561)) The banteng is another bovid that has to some degree been domesticated, but can also still be found in the wild in several Southeast Asian countries.  Based on their analysis, the authors concluded that the kouprey is more than likely just a hybrid originating from crosses between zebu cattle and the banteng. Now, some might argue that it is pretty bold to reach such a profound conclusion based on a very small sample size, and not surprisingly some have indeed so argued. They have pointed out that anatomical and even DNA evidence from their own studies did not support stripping the kouprey of its species status. ((Grigson, 2007. J Zool. 271:239; Hassanin and Robiquet, 2007. J. Zool. 271:246)) An alternative explanation might simply be that there has been introgression of DNA from one species into the other by occasional matings. And there is ample evidence that this has happened in other species. Cattle DNA is commonly found in the American bison, for example, because of past attempts by cattle breeders to generate what they thought would be more viable bison-cattle hybrids. ((Rasmussen et al., 2005. Mol. Reprod. Dev. 70:228))

What is clearly needed to settle the matter is additional analysis of nuclear DNA obtained from more than one kouprey. But if the animal has, indeed, already disappeared, that may prove to be difficult. ((Contributed by Michael Kubisch))

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New efforts to domesticate grasses down under

The Australian Research Council has awarded A$ 1 million to Professor Robert Henry of Southern Cross University to examine about 1000 native grass species as potential replacements for wheat, rice and maize. The grant is framed as a response to global warming, but it is pretty interesting under any circumstances. Henry, Director of Southern Cross University’s Centre for Plant Conservation Genetics, told the Australian Associated Press that

the project targets the accelerated domestication of native species which have lower tillage and fertiliser requirements and increased salt, shade, frost and or drought tolerances than the current introduced cereal and fodder crops.

Of course, those grasses have been around since the first farmers landed in Australia, but they never tried to do anything with them. Because they couldn’t?

There is a great opportunity to use the new techniques of modern biology to accelerate the domestication of some of the more promising Australian native species.

Preliminary results are expected within three years, and seeds will be made available through a partnership with Native Seeds Pty Ltd. We shall see.