If your mother grew up in hot tropical conditions, does that mean that also your children would fare better in terms of their growth in tropical conditions as compared descendants of (genetically similar) temperature zone grown parents? I do not know, but if your mother was a fish, this could be the case.
In startlingly simple (and hence pleasing) factorial laboratory experiment Salinas and Munch (2011) exposed sheepshead minnow (Cyprinodon variegates) eggs from the same population to different temperature treatments, and followed the growth of individuals in different temperature treatments generation after. They found that the growth performance in subsequent generations in respect temperature depended on parental temperate treatment. In high temperatures, descendants for parents grown in hot temperatures outperformed those grown in lower temperatures.
These results suggest existence of strong transgenerational environmental effects of fish growth. While there is perhaps nothing particularly new in existence of such effects per se, the real punch-line is in the magnitude of the observed effects: the observed transgenerational temperature effect exceed (or are comparable to) what could be obtained with genetic response to selection. Hence, the results hint about possible importance of transgenerational environmental and parental effects on accommodating challenges posed by warming climate.
Salinas S,Munch SB (2011) Thermal legacies: transgenerational effects of temperature on growth in a vertebrate. Ecology Letters DOI: 10.1111/j.1461-0248.2011.01721.x
4 Comments
This is an interesting result though not completely surprising as maternal environmental effects are known to exist in fish. However, this study stresses the fact that common garden experiments may not only reflect genetic differences among individuals but also differences in their maternal environments, right?
Traits expressed in F1-generation common garden individuals may be influenced cross-generational environmental and parental effects. These can be detected with appropriate experimental designs and checks, but ultimately, one would like to check generations ≥F2. Cross-generational effects are known from many vertebrates (including humans), but the points here were that (1) temperature dependent CGEs have apparently not been earlier demonstrated in fish, and (2) that the effects can be apparently really large – with implications in warming-world context.
This study interestingly links to an earlier published paper on the evolutionary recovery of Atlatic silverside after five generations of selective harvesting followed by five generations of random harvesting (http://blogs.helsinki.fi/egru-blog/2009/03/04/fast-recovery/ ; one of the co-authors is the same in both the studies). Even though temperatures did not vary here, other maternal environmental effects (e.g., egg size and quality) might have played affected phenotypic trends during and after selection. Nonetheless, trends were interpreted being entirely evolutionary.
Yep, another interesting thing that may play in is that the growth is also influenced by endogenous rhythms: in this really nice study they show that fish from the same stock grown under same conditions in different times of the year grow very differently:
http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8649.2011.03121.x/abstract
Whatever, interesting stuff. I was (naturally) left to think how the phenomenon described in Ecol Lett papers might interact with this:
http://www.springerlink.com/content/0040817k02115303/