GMOs down to the chromosome level
If don't like the concept of 'Frankenfoods,' I have bad news for you. U.S. researchers have developed an artificial chromosome for corn plants. The Chicago Tribune reports that researchers can now make chromosomes to order. These artificial chromosomes are accepted as natural by the plants and passed through generations. As the Monsanto Company bought rights to use this mini-chromosome stacking technology in corn, cotton, soybeans, and canola, I guess we'll soon eat food made from permanently genetically modified organisms (PGMOs?).
You can see above some images of the autonomous maize minichromosomes (MMCs) used by the researchers. Here is the caption as written by them: "(A) Fluorescent detection of nuclear-localized DsRed in MMC1 maize leaf; size bar, 50 µm. (B, C) Detection of DsRed sectors in a T2 plant leaf from event V-1 under (B) bright-field and (C) fluorescence microscopy; size bars, 0.5 mm. (D) high magnification view of image shown in (C) with the corresponding sector, comprising all cell layers, indicated by an asterisk; the edge of a sector that comprises only the adaxial cell layer is indicated by arrowheads, cells with typical DsRed expression are indicated by arrows. Size bar, 50 µm. (E) MMC consisting of a pCHR758 backbone and a centromere-derived insert, gene expression cassettes (grey), centromeric inserts (box), BglII restriction sites (arrowheads), and probes used for FISH and Southern blot analyses are indicated." (Credit: Chromatin, Inc.) And here is a link to a larger version.
This project research has been led by Daphne Preuss, a University of Chicago professor of molecular genetics, with the members of her lab. Preuss is also Chromatin's president and part of the Board of Governors for Argonne National Laboratory since 2003. Other researchers from the Universities of Chicago and North Carolina also participated to this project.
Here are some quotes from the Chicago Tribune article. "'This appears to be the tool that agricultural scientists and farmers have long dreamed of,' said Daphne Preuss, a University of Chicago professor of molecular genetics and Chromatin's president. Preuss said that adding a chromosome to a plant's genetic makeup is more useful to scientists than adding individual genes one at a time, as is the way most genetic engineering is done now. When a single gene is added to a plant its placement tends to be random, so many plants must be used to get a few that use the new gene to acquire a trait, such as better tolerance for drought. Often, a plant needs two or three new genes to acquire drought resistance, Preuss said, which is difficult to achieve using today's technology."
In "Transgenics transformed," a University of Chicago Medical Center news release (October 18, 2007), Preuss gives other details. "'This technology could be used to increase the hardiness, yield and nutritional content of crops,' she said. 'It could improve the production of ethanol or other biofuels. It could enable plants to make complex biochemicals, such as medicines, at very little expense.' It could also 'cut one to two years out of any new transgenic project,' said Preuss, who is taking a leave of absence from the University to bring this technology into the marketplace. 'You get a better product faster, which saves time, reduces costs, and frees up resources.'
This research work has been published in PLoS Genetics on October 19, 2007 under the somewhat cryptic name of "Meiotic Transmission of an In Vitro–Assembled Autonomous Maize Minichromosome." If you're intrigued by the 'meiotic' component of the title of the paper, please read the Wikipedia article about Meiosis.
Here is the beginning of the abstract of this scientific paper. "Autonomous chromosomes are generated in yeast (yeast artificial chromosomes) and human fibrosarcoma cells (human artificial chromosomes) by introducing purified DNA fragments that nucleate a kinetochore, replicate, and segregate to daughter cells. These autonomous minichromosomes are convenient for manipulating and delivering DNA segments containing multiple genes. In contrast, commercial production of transgenic crops relies on methods that integrate one or a few genes into host chromosomes; extensive screening to identify insertions with the desired expression level, copy number, structure, and genomic location; and long breeding programs to produce varieties that carry multiple transgenes. As a step toward improving transgenic crop production, we report the development of autonomous maize minichromosomes (MMCs)."
All of this research seems perfectly legitimate and might even be beneficial to all of us. But it also carries unknown risks by permanently altering some plants. What do you think? Drop me a note.
Sources: Jon Van, chicagotribune.com, October 19, 2007; and various websites
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