Transgene

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A new paper arising out of the collaborative phase of the TRANSGENE project, has now been published. 'Genetics without genes? The centrality of genetic markers in livestock genetics and genomics' is co-authored by James Lowe and Ann Bruce. It is based on close attention to the elucidation and use of genetic markers in the world of pig genetics and genomics, through studying the scientific literature, the history of particular genomics projects and initiatives, and oral history interviews.

The title comes from a telling quote by a prominent quantitative geneticist that Lowe and Bruce interviewed, Michael Goddard: “One of my colleagues complained I was a geneticist who didn’t study genes”. It is indeed the case that for geneticists who are aiming to make their work relevant for the purposes of animal breeding, it is often enough to find, map and be able to genotype genetic markers. These genetic markers need not be themselves responsible for any mechanism or function. All that matters is that they can be statistically associated with variation in phenotypic outcomes. They can then be incorporated into selective breeding programmes.

In the paper, Lowe and Bruce detail the properties of genetic markers that enable them both to perform this role, and that also allowed quantitative and molecular genetics (based on very different models of gene effects and methodologies) to intersect: markers are ontologically inert, internally heterogeneous and relational.

To quote from the paper: "Markers are ontologically inert because there are no necessary presumed structural or functional consequences dependent upon any one individual marker. They are internally heterogeneous, as the material nature of markers need not be of the same kind or congruent with other markers for them to be deemed comparable, equivalent or useful. They are relational in nature, as the value of an individual marker relies on its relations to other markers, and associations drawn with variation in phenotypic properties of interest."

The paper details the practices and uses of markers through the lens of different animal breeding strategies, from seeking positional candidate genes, to marker-assisted selection, to genomic selection.

It is based on a detailed study of the genetics concerning the pig, but aims to more broadly to call attention to other manifestations of 'genetics without genes', and to not rely on wholly gene-centric accounts of genetics.