A Gain-of-Function Polymorphism Controlling Complex Traits and Fitness in Nature

Abstract

Identifying the causal genes that control complex trait variation remains challenging, limiting our appreciation of the evolutionary processes that influence polymorphisms in nature. We cloned a QTL that controls plant defensive chemistry, damage by insect herbivores, survival, and reproduction in the natural environments where this polymorphism evolved. These ecological effects are driven by duplications in the BCMA loci controlling this QTL and by two selectively favored amino acid changes in the glucosinolate-biosynthetic P450s that they encode. These changes cause a gain of novel enzyme function, modulated by allelic differences in catalytic rate and gene copy number. Ecological interactions in diverse environments likely contribute to the widespread polymorphism of this biochemical function.

A below-ground herbivore shapes root defensive chemistry in natural plant populations

“…The pattern was most pronounced for the sesquiterpene lactone TA-G. As control and herbivore-infested populations of each area experienced similar abiotic and biotic conditions, and as no other root herbivore covaried with M. melolontha abundance, this screen suggests that M. melolontha can shape phenotypic variation of plant chemistry in nature. Such herbivore-associated patterns have often been predicted [48], but rarely been shown in nature either above [7,9] or below ground [21]. The positive association between TA-G concentration and M. melolontha abundance could be driven by two processes: first, TA-G may act as a defence and may be positively selected or induced by M. melolontha.…”

“…Recent studies have shown that the heterogeneous distribution of herbivores can shape plant defensive chemistry above ground [7][8][9]. Moreover, it was found that heterogeneity in herbivore communities maintains intraspecific variation in defence genes [10].…”

“…Insect herbivores, the most abundant and diverse plant consumers, have long been suspected to play an important role in this context [6]. Recent studies demonstrate that herbivore abundance can covary with the expression of plant defence metabolites [7], that the exclusion of phytophagous insects can lead to a relaxation of defences within a few generations [8] and that defence genes are under differential selection across environments [9,10]. Together, these studies show that the temporal and spatial variation in above-ground herbivore communities can shape plant defensive chemistry.…”

You stay, but I Hop: Host shifting near and far co‐dominated the evolution of Enchenopa treehoppers

“…Closely related plant species frequently share similarities in chemical compounds, nutrition, and phenology (Davies et al., 2013; Prasad et al., 2012). Therefore, host shifting is traditionally expected to occur more often between closely related host plants.…”

Caution required for handling genome editing technology

“…In the Cartagena Protocol on Biosafety, the technical legal term that is close to the GMO, "living modified organism" is stipulated as "any living organism However, other mutations may lead to a gain of function [15]. If organisms modified with genome editing in which a gain of function unintentionally arises are released without rigorous risk assessments, they may rapidly affect the local ecosystem by seriously threatening native species.…”