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Every science requires a special language because every science has its own ideas.
~Étienne Bonnot de Condillac (1715-1780)

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Term Definition

a joint venture between the International Center for Tropical Agriculture and the International Food Policy Research Institute working to reduce micronutrient malnutrition (hidden hunger) in Asia and Africa through the biofortification of seven food crops: beans, cassava, maize, pearl millet, rice, sweet potato, and wheat. Biofortification strategies are limited to precision breeding and reverse breeding; genetic engineering is not used. To date, provitamin-A enhanced sweet potato has been the only variety released.

hazard v. risk

electricity is an extremely hazardous thing, but because of the methods used to prevent exposure, the risks of using electricity are small. Some pesticides are extremely hazardous to human health and the environment; some involve little or no hazard. In the context of human health, highly hazardous pesticides should be avoided altogether, but exposure to less toxic pesticides can be prevented, making the risk extremely small. (The pesticide residues found on foods grown in the US are at such low levels that they are millions of times below a toxic dose.) In the context of the environment, assessments can be made to determine what risks a pesticide poses and whether changes to the use or proposed use are necessary to protect non-target species.

herbicide-tolerant crops

plants genetically engineered to be tolerant to the broad-spectrum herbicides glyphosate or glufosinate. When farmers spray a HT crop with its compatible herbicide, the weeds die, leaving the crop to grow. Otherwise, farmers control weeds with tillage, hand weeding, herbicides, or a combination of these. HT crops are compatible with no-till methods, which help improve soil fertility, reduce erodibility, increase carbon sequestration, and reduce fuel consumption. In general, farmers cultivate their fields less frequently. Resistance evolves in weeds through repeated applications of the same type of herbicide; ideally, farmers rotate between glyphosate-tolerant, glufosinate-tolerant, and conventional crops as part of integrated pest management strategies. In the absence of herbicide applications, HT food crops are no more likely to be invasive in agricultural fields or in natural habitats than their non-HT counterparts. See Roundup Ready, LibertyLink.

high-throughput screening

SULSA: high throughput screeningthe rapid testing of large libraries of biological molecules (mRNAs, proteins, or metabolites) to identify molecules that function in a biological system of interest.

homologous recombination

a type of genetic recombination that occurs during meiosis. Paired chromosomes from the male and female parents align so that similar DNA sequences cross over each other and exchange segments. After crossing over, each chromosome contains both maternal and paternal segments, and thereby new allele combinations in offspring.


genes related by descent from a common ancestral DNA sequence. Homologs may have been separated by a speciation event (see orthologs) or by a genetic duplication event (see paralogs).

homology tests

only certain short stretches of amino acids (the components of proteins) constitute allergenic sites.  As one of multiple methods of evaluating the potential allergy risks of GE crops, the amino acid sequences of transgenic proteins are scrutinized and compared to hundreds of thousands of other amino acid sequences to check for similarities with known allergens.


compostthe stable, long lasting remnant of decaying organic material that improves soil structure and increases water retention. Its nutritive qualities include trace elements and organic acids, without significant levels of nitrogen or phosphorus. In contrast, compost is organic matter in a state of partial decomposition.

hybrid breeding

by controlling pollination, two inbred plant lines are crossed. The progeny of the first cross (the F1 hybrids) are uniform because the genetic variation among them is low. They are vigorous because they often have two different versions of each gene variant, one of which is likely to be desirable. F1s also carry recessive genes for undesirable traits, which are liable to turn up unexpectedly in subsequent generations if seed is saved. Farmers choose hybrid seed when it’s high yielding or provides them with some other distinct advantage. See also classical breeding.

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