scholarly journals Adaptive divergence in shoot gravitropism creates hybrid sterility in an Australian wildflower

2021 ◽  
Vol 118 (47) ◽  
pp. e2004901118
Author(s):  
Melanie J. Wilkinson ◽  
Federico Roda ◽  
Greg M. Walter ◽  
Maddie E. James ◽  
Rick Nipper ◽  
...  

Natural selection is responsible for much of the diversity we see in nature. Just as it drives the evolution of new traits, it can also lead to new species. However, it is unclear whether natural selection conferring adaptation to local environments can drive speciation through the evolution of hybrid sterility between populations. Here, we show that adaptive divergence in shoot gravitropism, the ability of a plant’s shoot to bend upwards in response to the downward pull of gravity, contributes to the evolution of hybrid sterility in an Australian wildflower, Senecio lautus. We find that shoot gravitropism has evolved multiple times in association with plant height between adjacent populations inhabiting contrasting environments, suggesting that these traits have evolved by natural selection. We directly tested this prediction using a hybrid population subjected to eight rounds of recombination and three rounds of selection in the field. Our experiments revealed that shoot gravitropism responds to natural selection in the expected direction of the locally adapted population. Using the advanced hybrid population, we discovered that individuals with extreme differences in gravitropism had more sterile crosses than individuals with similar gravitropic responses, which were largely fertile, indicating that this adaptive trait is genetically correlated with hybrid sterility. Our results suggest that natural selection can drive the evolution of locally adaptive traits that also create hybrid sterility, thus revealing an evolutionary connection between local adaptation and the origin of new species.

2019 ◽  
Author(s):  
Melanie J. Wilkinson ◽  
Federico Roda ◽  
Greg M. Walter ◽  
Maddie E. James ◽  
Rick Nipper ◽  
...  

AbstractAdaptation to the local environment is a major driver of speciation. Yet, it remains largely unknown whether natural selection directly causes intrinsic reproductive isolation (hybrid sterility or inviability) between locally adapted populations. Here, we show that adaptive divergence in shoot gravitropism, the ability of a plant’s shoot to bend upwards in response to the downward pull of gravity, contributes to the evolution of intrinsic reproductive isolation in an Australian wildflower, Senecio lautus. We find that shoot gravitropism has evolved multiple times in association with plant height between adjacent populations inhabiting contrasting environments, suggesting that these traits have evolved by natural selection. We directly tested this prediction in multi-year reciprocal transplant experiments using hybrid populations. We show that shoot gravitropism and plant height respond to natural selection in the expected direction of the locally adapted population. Remarkably, we find that crossing F11 hybrid individuals with extreme differences in gravitropism significantly reduces their ability to produce seeds, providing strong evidence that this adaptive trait is genetically correlated with intrinsic reproductive isolation. Our results suggest that natural selection can drive the evolution of locally adaptive traits that incidentally create intrinsic reproductive isolation, thus increasing our understanding of the origin and maintenance of new species.


2018 ◽  
Vol 194 ◽  
pp. 188-192
Author(s):  
D. I. Shokasheva

Natural populations of crayfish are in depression in Russia and local species are not cultivated. In this situation, experimental cultivation of allochtonous australian crayfish Cherax quadricarinatus is conducted. This species is distinguished by high reproductive abilities and good consumer properties. It has domesticated in Russia spontaneously and produced 9–10 generations in Astrakhan Region. Certain natural selection in the process of domestication provides adaptive ability of this species to local environments and its capabil­ity to reproduce a viable progeny, so there is no doubts in good prospects of its cultivation in industrial conditions.


Ecologies ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 43-70
Author(s):  
Aabir Banerji

Adaptative traits enable organisms to survive and reproduce. Though these traits are often innate features (ones that may or may not exhibit variability in response to environmental cues or originate from horizontal gene transfer), this is not always the case. Many species endure natural selection not with the traits they possess intrinsically but with exogenous substances and abilities that they acquire from other species, via ecological interactions akin to outsourcing, pillaging, and fraud. Here, I review the mechanisms of this exogenous trait acquisition and highlight some of their repercussions and usefulness for natural resource management, industry, and human health.


2006 ◽  
Vol 361 (1475) ◽  
pp. 2045-2053 ◽  
Author(s):  
Daniel Falush ◽  
Mia Torpdahl ◽  
Xavier Didelot ◽  
Donald F Conrad ◽  
Daniel J Wilson ◽  
...  

In bacteria, DNA sequence mismatches act as a barrier to recombination between distantly related organisms and can potentially promote the cohesion of species. We have performed computer simulations which show that the homology dependence of recombination can cause de novo speciation in a neutrally evolving population once a critical population size has been exceeded. Our model can explain the patterns of divergence and genetic exchange observed in the genus Salmonella , without invoking either natural selection or geographical population subdivision. If this model was validated, based on extensive sequence data, it would imply that the named subspecies of Salmonella enterica correspond to good biological species, making species boundaries objective. However, multilocus sequence typing data, analysed using several conventional tools, provide a misleading impression of relationships within S. enterica subspecies enterica and do not provide the resolution to establish whether new species are presently being formed.


2003 ◽  
Vol 11 (04) ◽  
pp. 341-350 ◽  
Author(s):  
D. R. Forsdyke

Sometimes a cross between two individuals that appear to belong to the same species produces a sterile offspring (i.e., their hybrid is sterile). Thus, the two individuals appear reproductively isolated from each other. If each could find a compatible mate, then new species might emerge. At issue is whether the form of hybrid sterility that precedes sympatric differentiation into species is, in the general case, of genic or non-genic origin. Several recent papers lend the authority of William Bateson to the genic hypothesis, referring to the "Bateson–Dobzhansky–Muller hypothesis". All these papers cite a 1996 paper that, in turn, cites a 1909 paper of Bateson. However, from 1902 until 1926 the latter espoused a non-genic hypothesis that today would be classified as "chromosomal". Analysis of Bateson's 1909 text reveals no recantation. Bateson's non-genic view was similar to that advanced by Richard Goldschmidt in the 1940s. However, Bateson proposed a contribution from parents of abstract factors that, together in their hybrids, complement to bring about a negative effect (hybrid sterility). In contrast, Goldschmidt proposed that normally parents contribute complementary factors making parental chromosomes compatible at meiosis in their hybrids, which hence are fertile (i.e., the parental factors work together to produce a positive effect). When the factors are not sufficiently complementary the parental chromosomes are incompatible in their hybrids, which hence are sterile. The non-genic Batesonian–Goldschmidtian abstractions are now being fleshed-out chemically in terms of DNA base-composition differences.


2014 ◽  
Vol 183 (5) ◽  
pp. 671-681 ◽  
Author(s):  
Peter R. Grant ◽  
B. Rosemary Grant

2005 ◽  
Vol 56 ◽  
pp. 125-153
Author(s):  
Elliott Sober

‘There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know.’


2019 ◽  
Vol 116 (26) ◽  
pp. 12933-12941 ◽  
Author(s):  
David B. Lowry ◽  
John T. Lovell ◽  
Li Zhang ◽  
Jason Bonnette ◽  
Philip A. Fay ◽  
...  

Local adaptation is the process by which natural selection drives adaptive phenotypic divergence across environmental gradients. Theory suggests that local adaptation results from genetic trade-offs at individual genetic loci, where adaptation to one set of environmental conditions results in a cost to fitness in alternative environments. However, the degree to which there are costs associated with local adaptation is poorly understood because most of these experiments rely on two-site reciprocal transplant experiments. Here, we quantify the benefits and costs of locally adaptive loci across 17° of latitude in a four-grandparent outbred mapping population in outcrossing switchgrass (Panicum virgatumL.), an emerging biofuel crop and dominant tallgrass species. We conducted quantitative trait locus (QTL) mapping across 10 sites, ranging from Texas to South Dakota. This analysis revealed that beneficial biomass (fitness) QTL generally incur minimal costs when transplanted to other field sites distributed over a large climatic gradient over the 2 y of our study. Therefore, locally advantageous alleles could potentially be combined across multiple loci through breeding to create high-yielding regionally adapted cultivars.


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