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Wu SS, Jiang MT, Miao JL, Li MH, Wang JY, Shen LM, Peng DH, Lan SR, Zhai JW, Liu ZJ. Origin and diversification of a Himalayan orchid genus Pleione. Mol Phylogenet Evol 2023; 184:107797. [PMID: 37086913 DOI: 10.1016/j.ympev.2023.107797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/05/2023] [Accepted: 04/17/2023] [Indexed: 04/24/2023]
Abstract
Pleione is an orchid endemically distributed in high mountain areas across the Hengduan Mountains (HDM), Himalayas, Southeast Asia and South of China. The unique flower shapes, rich colors and immense medicinal importance of Pleione are valuable ornamental and economic resources. However, the phylogenetic relationships and evolutionary history of the genus have not yet been comprehensively resolved. Here, the evolutionary history of Pleione was investigated using single-copy gene single nucleotide polymorphisms and chloroplast genome datasets. The data revealed that Pleione could be divided into five clades. Discordance in topology between the two phylogenetic trees and network and D-statistic analyses indicated the occurrence of reticulate evolution in the genus. The evolution could be attributed to introgression and incomplete lineage sorting. Ancestral area reconstruction suggested that Pleione was originated from the HDM. Uplifting of the HDM drove rapid diversification by creating conditions favoring rapid speciation. This coincided with two periods of consolidation of the Asian monsoon climate, which caused the first rapid diversification of Pleione from 8.87 to 7.83 Mya, and a second rapid diversification started at around 4.05 Mya to Pleistocene. The interaction between Pleione and climate changes, especially the monsoons, led to the current distribution pattern and shaped the dormancy characteristic of the different clades. In addition to revealing the evolutionary relationship of Pleione with orogeny and climate changes, the findings of this study provide insights into the speciation and diversification mechanisms of plants in the East Asian flora.
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Affiliation(s)
- Sha-Sha Wu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ming-Tao Jiang
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jiang-Lin Miao
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ming-He Li
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jie-Yu Wang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Li-Ming Shen
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dong-Hui Peng
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Si-Ren Lan
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jun-Wen Zhai
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zhong-Jian Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Masonick P, Meyer A, Hulsey CD. Phylogenomic analyses show repeated evolution of hypertrophied lips among Lake Malawi cichlid fishes. Genome Biol Evol 2022; 14:6568296. [PMID: 35417557 PMCID: PMC9017819 DOI: 10.1093/gbe/evac051] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2022] [Indexed: 11/27/2022] Open
Abstract
Cichlid fishes have repeatedly evolved an astounding diversity of trophic morphologies. For example, hypertrophied lips have evolved multiple times in both African and Neotropical cichlids and could have even evolved convergently within single species assemblages such as African Lake Malawi cichlids. However, the extremely high diversification rate in Lake Malawi cichlids and extensive potential for hybridization has cast doubt on whether even genome-level phylogenetic reconstructions could delineate if these types of adaptations have evolved once or multiple times. To examine the evolution of this iconic trait using protein-coding and noncoding single nucleotide polymorphisms (SNPs), we analyzed the genomes of 86 Lake Malawi cichlid species, including 33 de novo resequenced genomes. Surprisingly, genome-wide protein-coding SNPs exhibited enough phylogenetic informativeness to reconstruct interspecific and intraspecific relationships of hypertrophied lip cichlids, although noncoding SNPs provided better support. However, thinning of noncoding SNPs indicated most discrepancies come from the relatively smaller number of protein-coding sites and not from fundamental differences in their phylogenetic informativeness. Both coding and noncoding reconstructions showed that several “sand-dwelling” hypertrophied lip species, sampled intraspecifically, form a clade interspersed with a few other nonhypertrophied lip lineages. We also recovered Abactochromis labrosus within the rock-dwelling “mbuna” lineage, starkly contrasting with the affinities of other hypertrophied lip taxa found in the largely sand-dwelling “nonmbuna” component of this radiation. Comparative analyses coupled with tests for introgression indicate there is no widespread introgression between the hypertrophied lip lineages and taken together suggest this trophic phenotype has likely evolved at least twice independently within-lake Malawi.
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Affiliation(s)
- Paul Masonick
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Axel Meyer
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - C Darrin Hulsey
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany.,Current Address: School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
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Urban S, Gerwin J, Hulsey CD, Meyer A, Kratochwil CF. The repeated evolution of stripe patterns is correlated with body morphology in the adaptive radiations of East African cichlid fishes. Ecol Evol 2022; 12:e8568. [PMID: 35154652 PMCID: PMC8820146 DOI: 10.1002/ece3.8568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/20/2021] [Accepted: 12/30/2021] [Indexed: 01/01/2023] Open
Abstract
Color patterns are often linked to the behavioral and morphological characteristics of an animal, contributing to the effectiveness of such patterns as antipredatory strategies. Species-rich adaptive radiations, such as the freshwater fish family Cichlidae, provide an exciting opportunity to study trait correlations at a macroevolutionary scale. Cichlids are also well known for their diversity and repeated evolution of color patterns and body morphology. To study the evolutionary dynamics between color patterns and body morphology, we used an extensive dataset of 461 species. A phylogenetic supertree of these species shows that stripe patterns evolved ~70 times independently and were lost again ~30 times. Moreover, stripe patterns show strong signs of correlated evolution with body elongation, suggesting that the stripes' effectiveness as antipredatory strategy might differ depending on the body shape. Using pedigree-based analyses, we show that stripes and body elongation segregate independently, indicating that the two traits are not genetically linked. Their correlation in nature is therefore likely maintained by correlational selection. Lastly, by performing a mate preference assay using a striped CRISPR-Cas9 mutant of a nonstriped species, we show that females do not differentiate between striped CRISPR mutant males and nonstriped wild-type males, suggesting that these patterns might be less important for species recognition and mate choice. In summary, our study suggests that the massive rates of repeated evolution of stripe patterns are shaped by correlational selection with body elongation, but not by sexual selection.
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Affiliation(s)
- Sabine Urban
- Chair in Zoology and Evolutionary BiologyDepartment of BiologyUniversity of KonstanzKonstanzGermany
| | - Jan Gerwin
- Chair in Zoology and Evolutionary BiologyDepartment of BiologyUniversity of KonstanzKonstanzGermany
| | - C. Darrin Hulsey
- Chair in Zoology and Evolutionary BiologyDepartment of BiologyUniversity of KonstanzKonstanzGermany
- Present address:
School of Biology and Environmental ScienceUniversity College DublinBelfieldIreland
| | - Axel Meyer
- Chair in Zoology and Evolutionary BiologyDepartment of BiologyUniversity of KonstanzKonstanzGermany
| | - Claudius F. Kratochwil
- Chair in Zoology and Evolutionary BiologyDepartment of BiologyUniversity of KonstanzKonstanzGermany
- Present address:
Institute of Biotechnology, HiLIFEUniversity of HelsinkiHelsinkiFinland
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Dong W, Liu Y, Li E, Xu C, Sun J, Li W, Zhou S, Zhang Z, Suo Z. Phylogenomics and biogeography of Catalpa (Bignoniaceae) reveal incomplete lineage sorting and three dispersal events. Mol Phylogenet Evol 2021; 166:107330. [PMID: 34687844 DOI: 10.1016/j.ympev.2021.107330] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 10/10/2021] [Accepted: 10/13/2021] [Indexed: 01/21/2023]
Abstract
Catalpa Scop. (Bignoniaceae) is a small genus (8 spp.) of trees that is disjunctly distributed among eastern Asia, eastern United States, and the West Indies. Catalpa bears beautiful inflorescences and have been cultivated as important ornamental trees for landscaping, gardening, and timber. However, the phylogenetic relationships and biogeographic history of the genus have remained unresolved. In this study, we used a large genomic dataset that includes data from the chloroplast (plastomes), and nuclear genomes (ITS and 5,759 single-copy nuclear genes) to reconstruct phylogenetic relationship within Catalpa, test interspecific gene flow events within the genus, and infer its biogeographic history. Our phylogenetic results indicate that Catalpa is monophyletic containing two main clades, section Catalpa and section Macrocatalpa. Section Catalpa is further divided into three subclades. While most relationships are congruent between the chloroplast and nuclear datasets, the position of C. ovata differs, likely due to incomplete lineage sorting. Interspecific gene flow events include C. bungei s.s. with vectors of inheritance from C. duclouxii and C. fargesii, supporting a combination of these three species and recognizing a broadly circumscribed C. bungei s.l. Our biogeographic study suggests three main dispersal events, two of which occurred during the Oligocene. The first dispersal event occurred from southwestern North America and Mexico into the Greater Antilles giving rise to the ancestor of the section of Macrocatalpa. The second dispersal event also occurred from southwestern North America and Mexico, but led to central and northern North America, subsequently reaching China through the Bering land bridge, and also reaching Europe through the North Atlantic land bridge. The third dispersal event took place in the Miocene from China to North America and gave rise to a clade composed of C. bignonioides and C. speciosa. This study uses a phylogenomic approach and biogeographical methods to infer the evolutionary history of Catalpa, highlighting issues associated with gene tree discordance, and suggesting that incomplete lineage sorting likely played an important role in the evolutionary history of Catalpa.
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Affiliation(s)
- Wenpan Dong
- Laboratory of Systematic Evolution and Biogeography of Woody Plants, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China.
| | - Yanlei Liu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Enze Li
- Laboratory of Systematic Evolution and Biogeography of Woody Plants, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Chao Xu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jiahui Sun
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Wenying Li
- Institute of Forestry New Technologies, Chinese Academy of Forestry, Beijing 100091, China
| | - Shiliang Zhou
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhixiang Zhang
- Laboratory of Systematic Evolution and Biogeography of Woody Plants, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Zhili Suo
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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Lecaudey LA, Singh P, Sturmbauer C, Duenser A, Gessl W, Ahi EP. Transcriptomics unravels molecular players shaping dorsal lip hypertrophy in the vacuum cleaner cichlid, Gnathochromis permaxillaris. BMC Genomics 2021; 22:506. [PMID: 34225643 PMCID: PMC8256507 DOI: 10.1186/s12864-021-07775-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/18/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Teleosts display a spectacular diversity of craniofacial adaptations that often mediates ecological specializations. A considerable amount of research has revealed molecular players underlying skeletal craniofacial morphologies, but less is known about soft craniofacial phenotypes. Here we focus on an example of lip hypertrophy in the benthivorous Lake Tangnayika cichlid, Gnathochromis permaxillaris, considered to be a morphological adaptation to extract invertebrates out of the uppermost layer of mud bottom. We investigate the molecular and regulatory basis of lip hypertrophy in G. permaxillaris using a comparative transcriptomic approach. RESULTS We identified a gene regulatory network involved in tissue overgrowth and cellular hypertrophy, potentially associated with the formation of a locally restricted hypertrophic lip in a teleost fish species. Of particular interest were the increased expression level of apoda and fhl2, as well as reduced expression of cyp1a, gimap8, lama5 and rasal3, in the hypertrophic lip region which have been implicated in lip formation in other vertebrates. Among the predicted upstream transcription factors, we found reduced expression of foxp1 in the hypertrophic lip region, which is known to act as repressor of cell growth and proliferation, and its function has been associated with hypertrophy of upper lip in human. CONCLUSION Our results provide a genetic foundation for future studies of molecular players shaping soft and exaggerated, but locally restricted, craniofacial morphological changes in fish and perhaps across vertebrates. In the future, we advocate integrating gene regulatory networks of various craniofacial phenotypes to understand how they collectively govern trophic and behavioural adaptations.
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Affiliation(s)
- Laurène Alicia Lecaudey
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Pooja Singh
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4 Canada
| | - Christian Sturmbauer
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
| | - Anna Duenser
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
| | - Wolfgang Gessl
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
| | - Ehsan Pashay Ahi
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
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Duchen P, Salamin N. A Cautionary Note on the Use of Genotype Callers in Phylogenomics. Syst Biol 2021; 70:844-854. [PMID: 33084875 PMCID: PMC8208803 DOI: 10.1093/sysbio/syaa081] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/02/2020] [Accepted: 10/02/2020] [Indexed: 12/13/2022] Open
Abstract
Next-generation-sequencing genotype callers are commonly used in studies to call variants from newly sequenced species. However, due to the current availability of genomic resources, it is still common practice to use only one reference genome for a given genus, or even one reference for an entire clade of a higher taxon. The problem with traditional genotype callers, such as the one from GATK, is that they are optimized for variant calling at the population level. However, when these callers are used at the phylogenetic level, the consequences for downstream analyses can be substantial. Here, we performed simulations to compare the performance between the genotype callers of GATK and ATLAS, and present their differences at various phylogenetic scales. We show that the genotype caller of GATK substantially underestimates the number of variants at the phylogenetic level, but not at the population level. We also found that the accuracy of heterozygote calls declines with increasing distance to the reference genome. We quantified this decline and found that it is very sharp in GATK, while ATLAS maintains high accuracy even at moderately divergent species from the reference. We further suggest that efforts should be taken towards acquiring more reference genomes per species, before pursuing high-scale phylogenomic studies. [ATLAS; efficiency of SNP calling; GATK; heterozygote calling; next-generation sequencing; reference genome; variant calling.].
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Affiliation(s)
- Pablo Duchen
- Department of Computational Biology, University of Lausanne, Quartier Sorge, 1015 Lausanne, Switzerland
| | - Nicolas Salamin
- Department of Computational Biology, University of Lausanne, Quartier Sorge, 1015 Lausanne, Switzerland
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Karagic N, Schneider RF, Meyer A, Hulsey CD. A Genomic Cluster Containing Novel and Conserved Genes is Associated with Cichlid Fish Dental Developmental Convergence. Mol Biol Evol 2021; 37:3165-3174. [PMID: 32579214 DOI: 10.1093/molbev/msaa153] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The two toothed jaws of cichlid fishes provide textbook examples of convergent evolution. Tooth phenotypes such as enlarged molar-like teeth used to process hard-shelled mollusks have evolved numerous times independently during cichlid diversification. Although the ecological benefit of molar-like teeth to crush prey is known, it is unclear whether the same molecular mechanisms underlie these convergent traits. To identify genes involved in the evolution and development of enlarged cichlid teeth, we performed RNA-seq on the serially homologous-toothed oral and pharyngeal jaws as well as the fourth toothless gill arch of Astatoreochromis alluaudi. We identified 27 genes that are highly upregulated on both tooth-bearing jaws compared with the toothless gill arch. Most of these genes have never been reported to play a role in tooth formation. Two of these genes (unk, rpfA) are not found in other vertebrate genomes but are present in all cichlid genomes. They also cluster genomically with two other highly expressed tooth genes (odam, scpp5) that exhibit conserved expression during vertebrate odontogenesis. Unk and rpfA were confirmed via in situ hybridization to be expressed in developing teeth of Astatotilapia burtoni. We then examined expression of the cluster's four genes in six evolutionarily independent and phylogenetically disparate cichlid species pairs each with a large- and a small-toothed species. Odam and unk commonly and scpp5 and rpfA always showed higher expression in larger toothed cichlid jaws. Convergent trophic adaptations across cichlid diversity are associated with the repeated developmental deployment of this genomic cluster containing conserved and novel cichlid-specific genes.
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Affiliation(s)
- Nidal Karagic
- Department for Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany
| | - Ralf F Schneider
- Department for Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany
| | - Axel Meyer
- Department for Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany
| | - C Darrin Hulsey
- Department for Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany
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Faber-Hammond JJ, Bezault E, Lunt DH, Joyce DA, Renn SCP. The Genomic Substrate for Adaptive Radiation: Copy Number Variation across 12 Tribes of African Cichlid Species. Genome Biol Evol 2020; 11:2856-2874. [PMID: 31504491 DOI: 10.1093/gbe/evz185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2019] [Indexed: 02/06/2023] Open
Abstract
The initial sequencing of five cichlid genomes revealed an accumulation of genetic variation, including extensive copy number variation in cichlid lineages particularly those that have undergone dramatic evolutionary radiation. Gene duplication has the potential to generate substantial molecular substrate for the origin of evolutionary novelty. We use array-based comparative heterologous genomic hybridization to identify copy number variation events (CNVEs) for 168 samples representing 53 cichlid species including the 5 species for which full genome sequence is available. We identify an average of 50-100 CNVEs per individual. For those species represented by multiple samples, we identify 150-200 total CNVEs suggesting a substantial amount of intraspecific variation. For these species, only ∼10% of the detected CNVEs are fixed. Hierarchical clustering of species according to CNVE data recapitulates phylogenetic relationships fairly well at both the tribe and radiation level. Although CNVEs are detected on all linkage groups, they tend to cluster in "hotspots" and are likely to contain and be flanked by transposable elements. Furthermore, we show that CNVEs impact functional categories of genes with potential roles in adaptive phenotypes that could reasonably promote divergence and speciation in the cichlid clade. These data contribute to a more complete understanding of the molecular basis for adaptive natural selection, speciation, and evolutionary radiation.
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Affiliation(s)
| | - Etienne Bezault
- BOREA Research Unit, MNHN, CNRS 7208, Sorbonne Université, IRD 207, UCN, UA, Paris, France
| | - David H Lunt
- Department of Biological and Marine Sciences, University of Hull, Hull Kingston-Upon-Hull, United Kingdom
| | - Domino A Joyce
- Department of Biological and Marine Sciences, University of Hull, Hull Kingston-Upon-Hull, United Kingdom
| | - Suzy C P Renn
- Department of Biology, Reed College, Portland OR 97202
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Hulsey CD, Alfaro ME, Zheng J, Meyer A, Holzman R. Pleiotropic jaw morphology links the evolution of mechanical modularity and functional feeding convergence in Lake Malawi cichlids. Proc Biol Sci 2019; 286:20182358. [PMID: 30963830 PMCID: PMC6408893 DOI: 10.1098/rspb.2018.2358] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/01/2019] [Indexed: 12/12/2022] Open
Abstract
Complexity in how mechanistic variation translates into ecological novelty could be critical to organismal diversification. For instance, when multiple distinct morphologies can generate the same mechanical or functional phenotype, this could mitigate trade-offs and/or provide alternative ways to meet the same ecological challenge. To investigate how this type of complexity shapes diversity in a classic adaptive radiation, we tested several evolutionary consequences of the anterior jaw four-bar linkage for Lake Malawi cichlid trophic diversification. Using a novel phylogenetic framework, we demonstrated that different mechanical outputs of the same four jaw elements are evolutionarily associated with both jaw protrusion distance and jaw protrusion angle. However, these two functional aspects of jaw protrusion have evolved independently. Additionally, although four-bar morphology showed little evidence for attraction to optima, there was substantial evidence of adaptive peaks for emergent four-bar linkage mechanics and jaw protrusion abilities among Malawi feeding guilds. Finally, we highlighted a clear case of two cichlid species that have -independently evolved to graze algae in less than 2 Myr and have converged on similar jaw protrusion abilities as well as four-bar linkage mechanics, but have evolved these similarities via non-convergent four-bar morphologies.
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Affiliation(s)
- C. Darrin Hulsey
- Department of Biology, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Michael E. Alfaro
- Department of Ecology & Evolutionary Biology, University of California-Los Angeles, 610 Charles E. Young Drive East, Los Angeles, CA 90095-7246, USA
| | - Jimmy Zheng
- Department of Ecology & Evolutionary Biology, University of California-Los Angeles, 610 Charles E. Young Drive East, Los Angeles, CA 90095-7246, USA
| | - Axel Meyer
- Department of Biology, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Roi Holzman
- Department of Zoology, Tel Aviv University and the Inter-University Institute for Marine Sciences, PO Box 469, Eilat 88103, Israel
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