The editorial board is seeking nominations for the Harry Smith Prize, which recognizes the best paper published in Molecular Ecology or Molecular Ecology Resources in the previous year by graduate students or early career scholars with no more than five years of postdoctoral or fellowship experience. The prize comes with a cash award of US$1000 and an announcement in the journal and in the Molecular Ecologist. The winner will also be asked to join a junior editorial board for the journal to offer advice on changing research needs and potentially serve as a guest editor. The winner of this annual prize is selected by the junior editorial board.
The prize is named after Professor Harry Smith FRS, who founded Molecular Ecology and served as both Chief and Managing Editor during the journal’s critical early years. He continued as the journal’s Managing Editor until 2008, and he went out of his way to encourage early career scholars. In addition to his editorial work, Harry was one of the world’s foremost researchers in photomorphogenesis, where he determined how plants respond to shading, leading to concepts such as “neighbour detection” and “shade avoidance,” which are fundamental to understanding plant responses to crowding and competition. More broadly his research provided an early example of how molecular data could inform ecology, and in 2008 he was awarded the Molecular Ecology Prize that recognized both his scientific and editorial contributions to the field.
Please send a PDF of the paper you are nominating, with a short supporting statement (no more than 250 words; longer submissions will not be accepted) directly to Dr. Kaichi Huang (kaichi.huang@botany.ubc.ca) and Dr. Arne Jacobs (arne.jacobs@glasgow.ac.uk) by Friday 31 March 2023. Self-nominations are encouraged.
We are soliciting nominations for the annual Molecular Ecology Prize.
The field of molecular ecology is young and inherently interdisciplinary. As a consequence, research in molecular ecology is not currently represented by a single scientific society, so there is no body that actively promotes the discipline or recognizes its pioneers. The editorial board of the journal Molecular Ecology therefore created the Molecular Ecology Prize in order to fill this void, and recognize significant contributions to this area of research. The prize selection committee is independent of the journal and its editorial board.
The prize will go to an outstanding scientist who has made significant contributions to molecular ecology. These contributions would mostly be scientific, but the door is open for other kinds of contributions that were crucial to the development of the field. The previous winners are: Godfrey Hewitt, John Avise, Pierre Taberlet, Harry Smith, Terry Burke, Josephine Pemberton, Deborah Charlesworth, Craig Moritz, Laurent Excoffier, Johanna Schmitt, Fred Allendorf, Louis Bernatchez, Nancy Moran, Robin Waples, Scott Edwards, Victoria Sork, Fuwen Wei, and Kerstin Johannesson.
Please send your nomination with a short supporting statement (no more than 250 words; longer submissions will not be accepted) and the candidate’s CV directly to Joanna Freeland (joannafreeland@trentu.ca) by Friday, March 31, 2023. Organized campaigns to submit multiple nominations for the same person are not necessary and can be counterproductive. Also, note that nominations from previous years do not roll over.
With thanks on behalf of the Molecular Ecology Prize Selection Committee.
In a recent paper in Molecular Ecology, Szukala et al. quantified the degree of gene expression and functional parallelism across polytopic divergence of montane and alpine ecotypes of in Heliosperma pusillum (Caryophyllaceae) and gained insights into the architecture of adaptive traits. They performed RNA-seq analyses of plants grown in a common garden and detected a large proportion of differentially expressed genes in each replicate ecotype pair. Functional enrichment of these genes, however, revealed that the traits affected by significant expression divergence are largely consistent across ecotype pairs, suggesting a polygenic architecture for the diverged adaptive traits and multiple routes for adaptation. A new genome assembly for H. pusillum was also presented in this study.
We sent a number of questions to lead authors of this work, Aglaia Szukala and Ovidiu Paun, to get more detail on this study.
Upper panels: Graphical representations of the alpine (A) and montane (M) ecotypes of Heliosperma pusillum and their ecological niches. Lower panel: Map showing the study sites of ecotype pairs that evolved in parallel.
What led to your interest in this topic / what was the motivation for this study?
We are fascinated by the concept of parallel evolution and the molecular mechanisms behind this process. Given that drift is a major driver of evolution and due to the traditional focus on mono- or oligogenic traits, parallel evolution has been considered to be a rare process until recently. However, together with the increasing understanding of polygenic adaptation (Barghi et al., 2020), it has become clear that parallel evolution is relatively frequent, with implications across evolutionary biology and ecology. Specifically, for our study, previous works (Trucchi et al., 2017; Bertel et al., 2018) reported some evidence that altitudinal ecotypes in H. pusillum diverged in parallel. We wanted to rigorously test this hypothesis using demographic modeling and understand the level of molecular parallelism, with regard to divergent gene expression and outlier SNPs.
What difficulties did you run into along the way?
For several reasons related to the planning of field work and the development of the wider project over years, we had to deal with uneven sampling sizes across populations, which needed to be taken into account, especially for the demographic modeling analyses. Fun fact: in reciprocal translocation experiments of a complementary study (Szukala et al., 2022) on the same species, whose data is also included in the present paper, we chose to use alpine microsites to plant our accessions that were fairly flat (in an otherwise steep area) and free of other plants. At the end of the vegetation season, those sites proved to be resting places for chamois which squeezed and munched most of our plants, while overfertilizing them. In previous years, when reciprocal transplantations were performed as preparation for this study, we faced droughts, poor germination and survival rates at some sites, leading to uneven sampling sizes across sites. Take-home message: experiments in the wild are always a challenge.
What is the biggest or most surprising innovation highlighted in this study?
It is unclear how much overlap of divergence outliers is to be expected across natural evolutionary replicates. Our study showed a surprisingly low amount of shared molecular differentiation, which we did not expect given that the geographic range considered is relatively small and our study system is in a phase of incipient speciation with no reproductive isolation detectable (Bertel et al., 2016). The extremely low sharing of differentially expressed genes and outlier SNPs, but high similarity of GO terms involved across independent divergence events, indicates that the polygenic architecture of traits is relevant for adaptation of these populations to distinct altitudinal zones in the Alps.
Moving forward, what are the next steps in this area of research?
We further investigated the role of phenotypic plasticity for the development of parallel evolution in our system (Szukala et al., 2022) towards a better understanding of the relative role of genetic and environmentally-induced phenotypic variation in such replicated divergence events. We are also interested if other molecular mechanisms, which are sensitive to environmental input, such as epigenetic signals, could play an important role in parallel evolution. Further, we wish to understand how polygenic adaptation affects signatures of parallel evolution. Very interesting is to question if adaptation can use different genes to produce similar outcomes even in very closely related lineages, and how frequent this process takes place compared to the re-use of standing variation.
Alpine (blue) and montane (light orange) ecotypes of Heliosperma pusillum and their environments. In the alpine environment glabrous plants grow on more humid screes and meadows, also in proximity of streams. In the montane environment below the tree line, pubescent plants typically grow under rocks overhangs or on the rock as chasmophytes. Photo credit: Szukala A and Paun O.
What would your message be for students about to start developing or using novel techniques in Molecular Ecology?
Being curious and exploiting the most advanced and newest methods is good, but don´t forget to be robust, careful, and bias-aware when it comes to the interpretation of results.
What have you learned about methods and resource development over the course of this project?
It is often difficult to quantify and describe results relative to expectations in an objective way, because it is hard to formulate objective expectations in natural systems.
Describe the significance of this research for the general scientific community in one sentence.
Repeated evolution of similar phenotypes can involve different sets of genes.
Describe the significance of this research for your scientific community in one sentence.
Polygenic traits offer different genetic substrates for parallel evolution of similar phenotypes.
References
Barghi N, Hermisson J, Schlötterer C. 2020. Polygenic adaptation: a unifying framework to understand positive selection. Nature Reviews Genetics 21: 769–781.
Bertel C, Hülber K, Frajman B, Schönswetter P. 2016. No evidence of intrinsic reproductive isolation between two reciprocally non-monophyletic, ecologically differentiated mountain plants at an early stage of speciation. Evolutionary Ecology 30: 1031–1042.
Bertel C, Rešetnik I, Frajman B, Erschbamer B, Hülber K, Schönswetter P. 2018. Natural selection drives parallel divergence in the mountain plant Heliosperma pusillum s.l. Oikos 127: 1355–1367.
Trucchi E, Frajman B, Haverkamp THA, Schönswetter P, Paun O. 2017. Genomic analyses suggest parallel ecological divergence in Heliosperma pusillum (Caryophyllaceae). New Phytologist 216: 267–278.
Szukala A, Bertel C, Frajman B, Schönswetter P, Paun O. 2022. Parallel adaptation to lower altitudes is associated with enhanced plasticity in Heliosperma pusillum (Caryophyllaceae). bioRxiv 2022.05.28.493825; doi: 10.1101/2022.05.28.493825.
Featured study
Szukala A, Lovegrove-Walsh J, Luqman H, Fior S, Wolfe TM, Frajman B, Schönswetter P, Paun O. 2022. Polygenic routes lead to parallel altitudinal adaptation in Heliosperma pusillum (Caryophyllaceae). Molecular Ecology. https://doi.org/10.1111/mec.16356.
The Molecular Ecology Prize Committee is pleased to announce that the 2022 Molecular Ecology prize has been awarded to Dr. Kerstin Johannesson, Professor of Marine Ecology, University of Gothenburg, Sweden. Trained as a marine ecologist, her research over the past 40 years has focussed on understanding how marine organisms become adapted to their environment. Towards this goal, she performed pioneering molecular ecology work that fully integrated ecological and molecular approaches to study the sea snail, Littorina saxatilis, which she developed into a model species. Her work has inspired numerous researchers across Europe to also use Littorina as an ideal model to study the ‘tug of war’ between evolutionary forces that have driven ecotypic divergence across different habitats of littoral zones. She has authored 150 peer-reviewed articles, which have been cited nearly 9,000 times with an h-index of 56. She has trained 35 Ph.D. students and postdocs from Europe and abroad. Her impressive accomplishments have earned her 10 major awards, the most prestigious being The Swedish Börssällskapet Research Award and election to the Royal Swedish Academy of Sciences. She also has received awards (e.g., the Swedish “Kunskapspriset”) in recognition of her outreach activities and the impact of her science on society. In brief, Dr. Johannesson has been a pioneer and is still an influential leader in the field of marine molecular ecology in Europe and beyond.
Dr. Johannesson joins the previous winners of the Molecular Ecology Prize: Godfrey Hewitt, John Avise, Pierre Taberlet, Harry Smith, Terry Burke, Josephine Pemberton, Deborah Charlesworth, Craig Moritz, Laurent Excoffier, Johanna Schmitt, Fred Allendorf, Louis Bernatchez, Nancy Moran, Robin Waples, Scott Edwards, Victoria Sork, and Fuwen Wei.
In a recent paper in Molecular Ecology, Espindola and Vázquez-Domínguez et al. combined comprehensive fieldwork, genetic analyses and a novel niche modeling approach to investigate population genetic patterns, distribution patterns of native and non-native red-eared slider turtle (Trachemys scripta elegans), one of the worst invasive species across the world, and its congeners. They found very little naturally occurring distribution overlap and genetic admixture between red-eared slider and other Trachemys species studied. In addition, they demonstrated that the native Trachemys species in Mexico have distinct climatic niche suitability, which probably prevents the invasion of red-eared slider in the area. However, major niche overlap was found between non-native red-eared slider and native species from different parts of the world, indicating that sites closer to ecological optima of invasive species have higher establishment risk than those closer to the niche-centre of the native species.
We sent a number of questions to lead authors of this work, Sayra Espindola and Ella Vázquez-Domínguez, to get more detail on this study.
What led to your interest in this topic / what was the motivation for this study?
We have interest in population genetics of invasive species. In addition, Trachemys scripta elegans, one of the World’s 100 worst invasive species, is native to NE North America, and several native congeneric species are naturally distributed along the eastern coast of Mexico, which is an extraordinary scenario to test the effect of congeners on potential invasion patterns and evaluate their climatic and niche differences.
Trachemys spp (T. scripta, T. venusta, T. cataspila, T. taylori) and their distributions along the west coast of USA and Mexico. Trachemys scripta (red dots) in Mexico is non-native. A turtle trapping net is shown. Figure credit: Sayra Espindola/Ella Vázquez-Domínguez
What difficulties did you run into along the way?
Maybe the most significant was that, at the time we did the molecular laboratory work, extracting DNA from samples that had been stored in formaldehyde (museum samples) was rather difficult, thus we could not obtain genomic data (SNPs) for those samples (extraction kits are much more efficient now). Nonetheless, we did sequence nuclear microsatellites loci, which provided adequate genetic information that enabled us to show the significant contemporary genetic differentiation present between native and non-native Trachemys scripta elegans individuals.
What is the biggest or most surprising innovation highlighted in this study?
There are two interesting findings. One is that non-native Trachemys scripta elegans individuals have very little naturally occurring distribution overlap and admixture with its congeners – they exhibited reduced gene flow and clear genetic separation despite having zones of contact. Also, we demonstrate that the native Trachemys species studied (T. cataspila, T. venusta) have distinct climatic niche suitability, which prevents the establishment of and displacement by the non-native Trachemys scripta elegans. Yet, as T. s. elegans has invaded and displaced native turtle species worldwide, we show that sites closer to T. s. elegans’ niche-center have higher establishment risk than those closer to the niche-center of the native species.
Moving forward, what are the next steps in this area of research?
We are working with our genomic data to identify loci under selection to evaluate the potential connection between specific genes and adaptive traits in these turtles. Considering the distinct climatic niches and distribution we found for the turtles, we are very kin to elucidate if there are adaptive differences among them. In addition, our results set the basis for future work – whole genome or gene-targeted sequencing, as well as a higher number of field-sampled individuals, would allow assessment of hybridization and specific gene introgression.
What would your message be for students about to start developing or using novel techniques in Molecular Ecology?
We would first tell them that molecular ecology research, combining ecological fieldwork and laboratory tasks, is absolutely amazing! We recommend choosing to work with the species/taxa that you more deeply like – this makes the journey very enjoyable; and also selecting a laboratory and research group with ample experience in molecular work and analyses, while at the same time not afraid of proposing novel questions and ways of analyzing them.
What have you learned about methods and resource development over the course of this project?
In this project, we proposed and developed a novel modeling approach, in which by contrasting the niche suitability of the species, we were able to include, indirectly, the interactions that can occur when a species is introduced to habitats occupied by other species. The model is based on analyses of climatic niche suitability and the environmental centrality hypothesis, where fitness is expected to be highest in sites with environments closest to the center of the niche of the species. The development of this model and algorithms required an immense number of trials and errors, and once we had the final version, we had to again improve it after revision. The lesson then is that developing analytical models can take a lot, lot of time, but it is always worth the while!
Little climatic niche overlap between Trachemys scripta and two of its congeners, T. venusta and T. cataspila. Figure credit: Sayra Espindola/Ella Vázquez-Domínguez
Describe the significance of this research for the general scientific community in one sentence.
The distribution, range limits and potential risk of the invasion of invasive species can be evaluated with genetic information and ecological niche modeling.
Describe the significance of this research for your scientific community in one sentence.
Evaluating interspecific interactions between native and non-native closely related species with genetic information and niche modeling approach was key to determine the distribution patterns, range limits and invasion risks of Trachemys scripta elegans.
Wetlands system in the valley of Cuatrocienegas, Coahuila, Mexico, where the endemic Trachemys taylori lives. Photo credit: Ella Vázquez-Domínguez
Espindola S, Vázquez-Domínguez E, Nakamura M, Osorio-Olvera L, Martínez-Meyer E, Myers EA, Overcast I, Reid BN, Burbrink FT. 2022. Complex genetic patterns and distribution limits mediated by native congeners of the worldwide invasive red-eared slider turtle. Molecular Ecology. https://doi.org/10.1111/mec.16356.
The editorial board recently established a prize that recognizes the best paper published in Molecular Ecology or Molecular Ecology Resources in the last year by graduate students or early career scholars with no more than five years of postdoctoral or fellowship experience. The prize is named after Professor Harry Smith FRS, who founded Molecular Ecology and served as both Chief and Managing Editor during the journal’s critical early years. He continued as the journal’s Managing Editor until 2008, and he went out of his way to encourage early career scholars. In addition to his editorial work, Harry was one of the world’s foremost researchers in photomorphogenesis, leading to concepts such as “neighbour detection” and “shade avoidance,” which are essential to understanding plant responses to crowding and competition. His research provided an early example of how molecular data could inform ecology, and in 2008 he was awarded the Molecular Ecology Prize that recognized both his scientific and editorial contributions to the field. As with the Molecular Ecology Prize, the winner of this annual prize is selected by an independent award committee, but the Harry Smith Prize comes with a 1,000 USD cash award, an announcement in the journal and on social media, as well as an invitation to join the Molecular Ecology Junior Editorial Board. Please send a short supporting statement (no more than 250 words; longer submissions will not be accepted) and PDF of the paper you are nominating to Dr. Alison Gonçalves Nazareno (alison_nazareno@yahoo.com.br) or Dr. Kaichi Huang (kaichi.huang@botany.ubc.ca) by Friday 29 April 2022. Self-nominations are also encouraged. Nominated papers must have been published in Molecular Ecology or Molecular Ecology Resources in 2021.
In a recent paper in Molecular Ecology, Tang et al. investigated genetic divergence of different subspecies of pale sand martin (Riparia diluta) using genome-wide data. They found that the subspecies in Central and East Asia, which vary only gradually in morphology, broadly represent three genetically differentiated lineages. No signs of gene flow were detected between two lineages that met at the eastern edge of the Qinghai-Tibetan Plateau, which is likely due to largely different breeding and migration timing. Limited mixed ancestries were found in Mongolian populations between two lineages that might take divided migration routes around the Qinghai-Tibetan Plateau, and the authors hypothesize that selection against hybrids with nonoptimal migration routes might restrict gene flow. See the full article for more details of the study and the interview with lead author Manuel Schweizer below for more stories behind this exciting work.
Pale sand martin Riparia diluta tibetana, Mongolia, June 2018. Photo Credit: Manuel Schweizer
What led to your interest in this topic / what was the motivation for this study? I studied pale sand martin in Central Asia as part of the work on a field guide to the birds of Central Asia, which was published in 2012. I was then fascinated by the fact that the different subspecies described for this species breed in completely different environments: Central Asian steppes and semi deserts, high altitude grasslands on the Qinghai-Tibetan Plateau, or lowland subtropical China. Although it was evident that morphological identification of single individuals of the different subspecies without context is not possible, I suspected that cryptic diversity might be involved in this complex. This was corroborated by mtDNA data that we published in 2018. Together with Gerald Heckel and our PhD student Qindong Tang, I wanted to investigate this further using genome-wide data and test if gene flow is reduced in areas of potential contact between evolutionary lineages.
Breeding site of pale sand martin on the east edge of Qinghai-Tibetan Plateau in Zoige (Sichuan Province, China). Photo Credit: Qindong Tang
What difficulties did you run into along the way? The biggest challenge was to get a comprehensive geographic sampling together. As pale sand martins breed in low densities only, this meant a lot of travelling. Fortunately, we could count on the great support of our collaboration partners and their network – Yang Liu from Sun Yat-sen University in Guangzhou, China, and Gombobaatar Sundev from the National University of Mongolia. Moreover, Qindong Tang made an incredible effort and did an excellent job during the fieldwork.
What is the biggest or most surprising innovation highlighted in this study? Given the absence of obvious sexually selected traits and only gradual morphological differentiation between the different evolutionary lineages of the pale sand martin, the level of genetic differences and the fact that they behave like different species at least at the eastern edge of the Qinghai-Tibetan Plateau is indeed surprising. So, we were left with the following question: what processes and mechanism prevent a complete mixing at secondary contact zones? We think that seasonal migration behavior might be an essential factor in maintaining genetic integrity of these morphologically cryptic evolutionary lineages.
Moving forward, what are the next steps in this area of research? The next step is evident: we need to study in detail migration behavior of the different lineages. The ranges of two of them meet in the area of a well-known avian migratory divide, where western lineages take a western migration route around the Qinghai-Tibetan Plateau to winter quarters in South Asia, and eastern lineages take an eastern route to Southeast Asia. This might also be the case in the pale sand martins and we hypothesize that hybrids might have nonoptimal intermediate migration routes and selection against them might restrict gene flow. This will need quite some field work and application of up-date technologies such as modern data loggers. Let’s hope that the development of the pandemic will allow field work again soon.
What would your message be for students about to start developing or using novel techniques in Molecular Ecology? It is best to get started and not be intimidated or even afraid. The easiest way to learn new methods is to start using them. It is also important to build a network of people who can be asked for support when problems arise.
What have you learned about methods and resource development over the course of this project? As always in studies with a phylogeographic background, sampling matters most. Try to organize a complete geographic sampling in the beginning of a project. Sampling in parts of the distribution area of our study system was planned in the third year of Qindong’s PhD, however, this could not be achieved due to the pandemic. As a consequence, we still lack samples from western Mongolia which would have been important and made the overall picture more comprehensive. This work did not include any development of new methods, however, a knowledge of state-of-the art methodological approaches is obviously always crucial.
Describe the significance of this research for the general scientific community in one sentence. Our study points towards contrasting migration behavior as an important factor in maintaining evolutionary diversity under morphological stasis.
Describe the significance of this research for your scientific community in one sentence. Our discovery of cryptic diversity in the pale sand martin indicates that evolutionary diversity might be underestimated even in such well-studied groups such as birds, and it suggests that it is worth having a closer look at widespread species occurring in different environments.
Photo of the first author Qindong Tang during the field work. Photo Credit: Qin HuangSampling team in Qinghai, PR China, June 2016. From left to right: Manuel Schweizer, Paul Walser Schwyzer, Yang Liu, Qin Huang, Yun Li and our driver. Photo Credit: Manuel SchweizerSampling team in Mongolia, June 2018. From left to right: Tuvshin Unenbat, Turmunbaatar Damba, Gombobaatar Sundev, Paul Walser Schwyzer, Manuel Schweizer, Silvia Zumbach, Sarangua Bayrgerel. Photo Credit: Manuel Schweizer
Tang Q, Burri R, Liu Y, Suh A, Sundev G, Heckel G, Schweizer M. 2022. Seasonal migration patterns and the maintenance of evolutionary diversity in a cryptic bird radiation. Molecular Ecology. https://doi.org/10.1111/mec.16241.
Molecular Ecology Spotlight 