Details of Award
NERC Reference : NE/L012030/1
An archaeogenomic approach to maize evolution, adaptation, and biodiversity in North America
Fellowship Award
- Fellow:
- Dr L Kistler, University of Warwick, School of Life Sciences
- Grant held at:
- University of Warwick, School of Life Sciences
- Science Area:
- Terrestrial
- Overall Classification:
- Terrestrial
- ENRIs:
- Biodiversity
- Environmental Risks and Hazards
- Global Change
- Science Topics:
- Landscape & Environ. Archaeol.
- Population Ecology
- Genome rearrangements
- Genome organisation
- Genome organisation
- Environmental Genomics
- Abstract:
- Maize (or corn, Zea mays) is one of the most important crop plants worldwide. It is grown on six continents, is one of the top three staple crops for human consumption, feeds livestock worldwide, and helps fill a growing demand for ethanol-based fossil fuel alternatives. Maize adapts readily to diverse environments, and as a result, it is grown in an incredible range of ecological settings, making it a valuable asset to global food production and food security. This remarkable level of biodiversity is due in part to an abundance of transposable elements (TEs) in the maize genome; short, non-coding regions of DNA capable of rapidly altering the genome at a structural level by self-propagating throughout the genome and interrupting normal DNA replication. The resulting random alterations to the genome can be detrimental to the host organism, but can also introduce variation that is beneficial in certain evolutionary contexts. TE replication occurs in episodic bursts rather than at a predictable, steady pace, and these episodes are known to occur as a direct result of environmental stressors, such as those encountered when a domestic species is introduced to an unfamiliar habitat. In sum, when maize is introduced to a new habitat with environmental conditions such as low rainfall, a short growing season, or high altitude, these stressors can drive a surge in TE activity that rapidly introduces an abundance of random variation into the genome. Some of this variation could alter genetic pathways in ways that confer an advantage in the new habitat. Such variation would be extremely beneficial to the population, and under human cultivation, would rapidly be propagated throughout the crop fields by artificial selection. We believe that much of maize's robust adaptation to diverse habitats is driven by this process. The origins of maize can be traced to teosinte, a wild tropical grass native to Mexico that bears little resemblance to the familiar crop plant, but was being acted upon evolutionarily by human use and selection beginning 7,000-9,000 years ago (BP). Teosinte is not terribly useful to humans in its wild form, but selection for a few key traits early in the domestication process made it a high-yielding and robust crop plant. By the time Europeans arrive in the Americas, extremely diverse and well-adapted landraces were being intensively cultivated throughout the New World. Maize was carried northward out of Mexico to the American Southwest around 4100 BP, where it came to form an important part of the local diet. Around 2100 BP, maize was brought into eastern North America, but it made no significant dietary contribution until 1100 BP, when it suddenly became the dominant crop of the Eastern Woodlands, and was involved in major social and political changes occurring in the region. We suggest that maize underwent a period of local evolution driven by TE activity after arriving in eastern North America, without which the introduced southwestern varieties would have been unsuitable for such broad-scale agricultural intensification a thousand years after their arrival. We propose to isolate and analyze ancient DNA from archaeological eastern North American maize to identify patterns of TE activity suggesting adaptation to local conditions, and modern genomic methods with North American landraces to identify candidate genes that might have been affected by TE activity, and that therefore might have been involved in local adaptation. In addition, we propose to grow southwestern maize varieties in a simulated eastern North American environment to test whether TE activity is inducible by the inherent ecological stressors placed on non-local landraces. Our study will help us understand the fundamental mechanisms underlying biodiversity in one of the world's most important crop plants, a prospect with profound implications for global food security and ecosystem health in the face of climate change and declining crop biodiversity.
- NERC Reference:
- NE/L012030/1
- Grant Stage:
- Completed
- Scheme:
- Research Fellowship
- Grant Status:
- Closed
- Programme:
- Omics Fellowships
This fellowship award has a total value of £558,762
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Estate Costs | DI - Staff | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|
| £121,058 | £145,437 | £70,969 | £205,301 | £6,942 | £9,057 |
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