Getting ready for changing climates

Four papers together give an insight into what global warming promises for agriculture and agriculturalists, and how to deal with it.

ResearchBlogging.orgSome people will tell you that global warming is something we can cope with because it won’t actually create any new climates, just shift the old ones around a bit on the the surface of the Earth. They’re wrong. ((Williams, J. W., Jackson, S. T., & Kutzbach, J. E. (2007). Projected distributions of novel and disappearing climates by 2100 AD. Proceedings of the National Academy of Sciences of the United States of America, 104(14), 5738-5742.)) John Williams and his colleagues published an article in PNAS in the spring that shows conclusively that even the IPCC’s B1 scenario, in which modest reduction sees CO2 stabilized at 550 parts per million by 2100 AD, creates considerable risk of completely novel climates.

Continue reading “Getting ready for changing climates”

Seed conservation: cold, or dry?

Another fine guest post from Jacob van Etten.

Places with extreme conditions are good for conservation, whether it be Timbuktu with its dry, hot climate for books or Spitsbergen with its freezing cold for crop seeds. Next year the seeds will start to come to Spitsbergen from across the world to stock the “doomsday seed vault”. Right now the vault is being cooled down, to be reaching -18°C soon.

Low temperatures are key to ex situ conservation of seeds. Cold chambers and freezers stuffed with seeds are found near any plant scientist around the world. The Svalbard project is not only unique because of the size of the vault but also because of its location. The low temperatures on the island will make the vault less expensive to cool as well as less vulnerable to energy failure, a common preoccupation of seed bank managers in those countries where tropical temperatures, unreliable energy networks and unpaid bills tend to converge. An alternative solution, however, seems to be on the horizon. The latest Technology Quarterly section of The Economist runs an interesting story about dry storage of biological materials at room temperature. Wrapped in polymers or sugars, DNA molecules are less vulnerable to degeneration. Perhaps this technology will also be available to seeds some day?

Continue reading “Seed conservation: cold, or dry?”

Stem cells and endangered livestock breeds

A group of scientists at the Massachusetts Institute of Technology has managed to turn fibroblasts, cells abundant in connective tissues, back into pluripotent, i.e. non-differentiated, stem cells. ((Wernig et al. 2007. In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state. Nature.))  This has caused quite a stir — and for good reason.

Because stem cells are pluripotent, they can in theory be turned into virtually any cell type in the body. Needless to say, such cells have tremendous potential for therapeutic intervention in all sorts of human maladies that result from cellular death or injury. Until now there have been mainly two ways to obtain stem cells: one involves the generation and subsequent destruction of  an embryo to extract embryonic (ES) stem cells,  the other relies on  isolation of adult stem cells, which have been found in all sorts of locations from the spinal chord to dental pulp.

But there are limitations and issues with both approaches: the derivation of ES cells evokes moral objections from many quarters because it necessitates the destruction of an embryo, while the use of adult stem cells is at present fraught with doubts about whether such cells are truly pluripotent. This is why this new development is considered such a breakthrough.

Why would a method to generate stem cells be relevant for saving endangered animal breeds? What if it were possible to turn pluripotent stem cells into eggs and sperm cells? Impossible, you say? Well, consider this: an article appeared in 2003 in the journal Science claiming that scientists had, indeed, managed to generate what seemed to look like egg cells from embryonic mouse stem cells. ((Hübner et al. 2003. Derivation of oocytes from mouse embryonic stem cells. Science 300:1251-56.)) Several other groups meanwhile seem to have coaxed stem cells to turn into primitive sperm cells, and at least one report has described the use of such sperm cells to generate live mouse offspring. ((Nayernia et al. 2006. In vitro-differentiated embryonic stem cells give rise to male gametes that can generate offspring mice. Developmental Cell 11:125-32.))

Much of this remains to be worked out and confirmed by other scientists, and given the incredibly complicated process of meiosis and maturation that egg and sperm cells have to undergo before becoming truly functional, many doubt this kind of approach will ever be feasible. Even the conversion of fibroblasts into stem cells is at present still very complicated and this recent report represents mostly a proof of principle. 

But just imagine if this were all to work: it might then be possible to go out into a field, pick a few small chunks of ear tissue from as many endangered cattle, goats or pigs as you want,  isolate the fibroblasts, turn them into stem cells, coax those into becoming eggs and sperm, make embryos, and put them into your freezer, where they could remain indefinitely. You could do this probably with a lot less effort than it often takes to ensure preservation of  rare animals in situ and would, moreover, be able to bank as much of a breed’s genomic variation as you’d like.

Maybe this will remain science fiction. Then again, nobody thought a sheep could be cloned either…. ((Contributed by H. Michael Kubisch))

Happy birthday, chicken

edm-broilers.jpg Those chickens give me the willies. Like the mythical boiled frog, I hadn’t been really aware of what has been done to the broiler chicken in the past 50 years. I knew, of course. But I didn’t know. Now, thanks to an almost incidental image on the web site of CBC news in Canada, I do. ((The photo is by Martin Zuidhof, a researcher at the University of Alberta. I wish I could find a bigger version.))

The reason for the CBC story, amplified in a press release from the University of Alberta, is that it is 50 years since the Poultry Scientists at the University of Alberta decided “to preserve a strain of broiler chicken to ensure it would live on”. The lovable boffins decided to celebrate with a bit of a party, which included a special feed for the hens, “topped off with birthday candles”. There is, of course, a serious point to all this: birds back then may have been five times smaller, and much slower growing, but they had some fine genes that the far-sighted scientists deemed worth preserving.

“At the time, it was thought by Agriculture Canada that genetic progress was happening pretty quickly and that a random-bred standard should be maintained to preserve those genetics,” said Doug Korver, a professor of poultry nutrition in the Faculty of Agriculture, Forestry, and Home Economics. “Preserving genetic stocks is important in poultry, because we use so few individual strains to produce a lot of the poultry in the world.”
“If we ever have to fall back on some traits that have been lost in the commercial genetic selection process, then we have that resource available to us to rely on again,” Martin Zuidhof told CBC News.

The crucial phrase is “random-bred”. Each year the scientists choose 400 eggs from 300 hens and use them to rejuvenate the flock. There is no selection, so the chances are good that all the genetic diversity is being preserved. Indeed, at a visible, phenotypic level, diversity is increasing. The original flock was all-white. Fifty years on, coloured birds stroll among their white brethren.

Among the invisible differences between the random-bred flock and modern selections is the response to infection. Modern birds do not divert many resources away from growth and into an immune response. “Old” birds mount a vigorous immune response, but at the expense of growth. It is this shift in priorities that underlies the almost unbelievable progress of the modern bird; it is selected to grow, quickly and efficiently, and infections are a distraction. The day may come when modern flocks need a better immune response, or maybe just resistance genes.

One of the issues is food security, said Zuidhof, citing the threat of bird flus, which wipe out entire flocks of chickens almost overnight. “Should something happen in the industry that caused a major loss of numbers, we have a strain that is unselected and closer to the indigenous chicken. It is just one more approach to securing the food supply going into the future.”

So how much has the modern bird changed? It is ready for the table in 35 days — that’s five weeks — versus the 90 days, almost 13 weeks, of its ancestor, which was already pretty well selected. Zuidhof reckons about 80% of the increase is down to genetics and just 20% to better nutrition and housing.

“People often assume that because chickens are so different from how they were 50 years ago, it must be to some technology like hormones. It’s all based on traditional selection of the best individuals and nutrition.”

Nevertheless, the scientists know that they don’t know when they might need to go back to the relatively unselected founder stock, hence the happy birthday to that genepool. And if its worth preserving the basis of the modern broiler flock, how much more important might it be to preserve the rest of the chicken’s genetic diversity?

Monopsony

Thanks to our occasional contributor Jacob van Etten for the following article on markets and agrobiodiversity. 

Monopoly happens when there is only one seller for a certain product. Monopsony, this week’s new word, happens when there is only one buyer. And when this happens, it is also likely that this single buyer will impose some rigid standards. And then the industrial buyer makes fake diversity by making slightly different mixes of standard components:

One technique retail oligopolies use is flood the shelves with a pseudo variety of similar products made in almost exactly the same way, so that minor vendors that offer real variety can be elbowed out. The beer industry is a great example of this trend.

In other words, agricultural biodiversity is being replaced with industrial diversity. Monopsony is growing in the US wine market. If climate change will push wine production to the north, will Canadian and Swedish vineyards become planted only to the few grape varieties demanded by the monopsonists ((There was a nice map in the November 2007 French National Geographic that shows how viticulture will move northwards, based on data by Gregory Jones, whose home page has a number of interesting articles on this, but none as the NG map.))?

The role that markets play in biodiversity conservation as well as local food provision is also the subject of a recent article, published in the International Journal of Agricultural Sustainability. The article is behind a pay-wall, but the PhD dissertation (in Spanish) on which it based and a colorful brochure are available for free.

Neus Martí and Michel Pimbert explain that in the Peruvian Andes, local communities organized barter markets to exchange local food products, while the economy of the region was pushed towards commercial agriculture. The barter markets permit a commercial exchange of agricultural products that is economically horizontal (between equals) and ecologically vertical (between ecological floors in the mountain landscape), whereas neo-liberal policy promote something that is the other way around.

The barter markets also happen to be good for biodiversity. All crops that are sold for money may also be bartered, but the reverse is not true. Many crop landraces and wild foods exchanged in barter markets are never sold in money-based markets.

So, don’t blame the market. Blame the monopsonists.