A potential solution for global energy demands is the use of Poplar, a fast-growing tree with high yields, for biofuels. To get the most out of Poplar plantations, varieties that are the best fit for the conditions — ones with disease resistance or higher yields, for example — are desired. But do these plantations of new, non-native (exotic) species impact nearby native populations of Poplar? In particular, is the genetic makeup of the native populations being altered by interactions with the exotic species?
In the October issue of the American Journal of Botany (http://www.amjbot.org/cgi/reprint/97/10/1688), Dr. Nathalie Isabel and colleagues tackled these issues by conducting a scientific risk assessment on the introduction of exotic species of Poplar (complex hybrids primarily made up of Populus nigra, P. trichocarpa, and P. maximowiczii) and the resulting impact on three native populations of Poplar species (P. deltoides and P. balsamifera) at two different locations over 3 years.
The researchers monitored gene flow — the passing of genetic information (alleles) between two populations — resulting from spontaneous hybridization between exotic and native populations. By looking for specific DNA signatures, called SNPs, they determined who the father species was for individual offspring. These paternity tests revealed that complex patterns of hybridization were occurring. All five species were capable of producing hybrids with the native populations, but when the native population was large, the native species were more successful; native species represented more than 95% of the parental alleles.
After the initial hybridization, the new genetic makeup may persist in the population through the generations (introgression) or be lost over time. The long-term effects of hybridization “depend on the ability of the hybrids to become established in natural forests and to subsequently reproduce,” Isabel said. “Thus, there is a need to monitor multiple steps of the introgression process for poplars.”
The risk of introgression is likely to be higher for small populations of native Poplars (ex: in disturbed agricultural landscapes) compared to more densely populated areas. This has important implications for further steps (ex: modeling introgression) and the development of regulatory guidelines for the commercial release of plants with novel traits, and for other cases where the rate of gene flow from plantations into natural populations should be kept to a minimum.
CITATION: Patrick G. Meirmans, Manuel Lamothe, Marie-Claude Gros-Louis, Damase Khasa, Pierre Périnet, Jean Bousquet, and Nathalie Isabel (2010). Complex patterns of hybridization between exotic and native North American poplar species. American Journal of Botany 97(10): 1688-1697. DOI: 10.3732/ajb.0900271
The full article in the link mentioned is available for no charge for 30 days following the date of this summary at http://www.amjbot.org/cgi/reprint/97/10/1688. After this date, reporters may contact Richard Hund at [email protected] for a copy of the article.
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As development among the global population increases, along with the number of people on the planet, so does our need for energy to maintain our societies. All of the energy on our planet, and all of the energy we use to sustain our societies ultimately comes from the sun. Different fuel sources require a different number of conversions on the energy before we use them. Oil for instance starts out as energy from the sun, which is sequestered in plants (the first conversion), then animals eat the plants (second conversion), and these all die, and gradually over millions of years (many conversions) this dead organic matter gradually turns into a concentrated source of energy. Biofuels are simply biological energy conversion machines. They simply sequester the energy from the sun, which we then convert to forms that are more useful for us. The fewer steps we have between the sun’s energy, and our use of it, the more efficient it is, and the less impact it has on the environment as a whole. Using the sun’s energy directly, or obtaining energy in the same manner as the sun (nuclear fusion) has the potential to provide immense amounts of energy far exceeding the amount we currently use today; with minimal impact.
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