Anyone who tells you they have a super food or a potion to impact a complex trait is sellinf you something. Life is rarely simple. The things we care about most, from crop yields to disease risks, are instead "complex traits."
Human height is a textbook example of a complex trait while attributes like risk for a particular human disease are shaped by multiple genetic and environmental influences.
The value of the Science 2.0 approach, and the wealth of Big Data that geneticists now have available, is in finding the genes involved and then quantifying their importance when other circumstances are factored in.
Historically, making claims about genetics has meant finding two individuals that differ in key ways—for example, a large mouse and a small mouse—and then studying their descendants, looking for genes that tend to be inherited with the trait value of interest.
That only implicates a broad genomic region, and the identities of the crucial genes often remain a mystery. But the tools are available now to make that more robust, by founding the breeding population with multiple, genetically diverse parents. Mapping complex trait genes in multi-parental populations means really being able to converge on complex traits
18 articles in GENETICS and G3: Genes|Genomes|Genetics describe methods and applications in a wide range of organisms, including mice, fruit flies, and maize. Among the advances are the creation of a multiparental population of wheat, methods for use with the Diversity Outbred and Collaborative Cross mouse populations, and the identification of nicotine resistance genes in fruit flies. The power of the approach for disease genetics is highlighted in an article describing how a multiparental rat population was used to find a human gene variant that affects insulin levels.
Because the field is so new, geneticists are still developing the best methods for creating and analyzing multiparental populations, but this is a good start.
"These collections of multiparental strains are extremely powerful and greatly accelerate discovery. For example, in one of the articles, researchers report using a multiparental population to rapidly identify fruit fly genome regions associated with the toxicity of chemotherapy drugs. The authors could then examine these regions to find several candidate causative genes," said Dirk-Jan de Koning, Professor at the Swedish University of Agricultural Sciences, Deputy Editor-in-Chief, Complex Traits, at G3, and an editor of the new collection. "Using standard two-parent crosses, they would have been stuck with unmanageably large regions each containing hundreds or even thousands of candidate genes."
"This collection will move the field forward by stimulating discussion between different disciplines and research communities," said Lauren McIntyre, Professor at the University of Florida, and an editor of the collection. "To help foster this ongoing exchange, the collection will continue to publish new articles, and all associated data will be freely available."
In an editorial, McIntyre and de Koning describe how the idea for the multiparental populations collection was born and how scientific society journals like GENETICS and G3 can advance new research fields.