Genetic modification (GM) sounds very laboratory-based – people in white coats inserting and deleting genes – but the vast majority of GM work was completed in the field through selective breeding.
Early Middle Eastern farmers collected grain from natural grasslands, but they needed to time their harvest very carefully. If they were too early the grain wouldn’t store well, and if they were too late the grain would spread over the ground making collection difficult. At some stage, one of these early farmers must have noticed that some heads remained fixed on their stems even after the grain was fully dry. He obviously didn’t understand this at the time, but these were plants with a mutation in the genes controlling seed dispersal.
Farmers began preferentially choosing plants with this useful mutation and planting them, perhaps the first case of breeding and selecting for a novel trait.
Breeding involves utilising genetic variation to produce new combinations of genes and gene variants. A breeder will cross two different lines and then select offspring that have improved performance. But for many crops the level of diversity available within the elite germplasm pool is very narrow and breeders must look further afield for novel variation. The normal number of genes present in a crop plant is around 30,000 to 40,000 – the same as for humans. In making the crosses all 30,000 genes from the wild relative are introduced but the breeder may only want one gene.
Scientifically the ideal solution would be to be able to take a gene from any source and introduce it into your crop plant to change the plant’s characteristics. This would allow breeders to use variation from diverse sources and make changes just one gene at a time without the extensive collateral damage done by mutagenesis or wide crosses. This is what genetic engineering offers.
Read the full, original article: GM techniques: from the field to the laboratory (and back again)