I asked Robin Probert at the Millennium Seed Bank at Kew to comment on the recent paper “Variation in seed dormancy quantitative trait loci in Arabidopsis thaliana originating from one site.” Here’s the abstract:
A Quantitative Trait Locus (QTL) analysis was performed using two novel Recombinant Inbred Line (RIL) populations, derived from the progeny between two Arabidopsis thaliana genotypes collected at the same site in Kyoto (Japan) crossed with the reference laboratory strain Landsberg erecta (Ler). We used these two RIL populations to determine the genetic basis of seed dormancy and flowering time, which are assumed to be the main traits controlling life history variation in Arabidopsis. The analysis revealed quantitative variation for seed dormancy that is associated with allelic variation at the seed dormancy QTL DOG1 (for Delay Of Germination 1) in one population and at DOG6 in both. These DOG QTL have been previously identified using mapping populations derived from accessions collected at different sites around the world. Genetic variation within a population may enhance its ability to respond accurately to variation within and between seasons. In contrast, variation for flowering time, which also segregated within each mapping population, is mainly governed by the same QTL.
And here’s what Robin had to say:
Sufficient genetic variation for seed dormancy in single populations, especially annuals, is not surprising and we found this many years ago when we were working on Ranunculus sceleratus. ((Probert, R.J., Dickie, J.B. and Hart, M.R. (1989) Analysis of the effect of cold stratification on the germination response to light and alternating temperatures in selected seed populations of Ranunculus sceleratus L. Journal of Experimental Botany, 40, 293-301)) In those days we didn’t have the molecular tools now available but is was very clear that individual genotypes selected from single populations had the ability to behave as winter or summer annuals. Nevertheless, there are countless examples in the literature that demonstrate that germination and dormancy are highly adapted to local climate. I guess what the recent papers reveal is that hidden within those striking patterns of adaptation is sufficient genetic variation to cope with climate variation. Whether this will be enough to cope with the scale and rapidity of climate change is another matter. Time will tell.
Indeed it will. While we wait, can anyone explain that “In contrast…” at the end of the abstract?
The contrast is:
Variation for seed dormancy controlled by one QTL in one population and two QTLs in the other (of which one is different from the first population).
versus
Variation for flowering time controlled by the same QTL in both populations.
Not much of a contrast. Could have chosen a better word.