1
|
Marconi A, Vernaz G, Karunaratna A, Ngochera MJ, Durbin R, Santos ME. Genetic and Developmental Divergence in the Neural Crest Program between Cichlid Fish Species. Mol Biol Evol 2024; 41:msae217. [PMID: 39412298 PMCID: PMC11558072 DOI: 10.1093/molbev/msae217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 10/07/2024] [Accepted: 10/09/2024] [Indexed: 10/30/2024] Open
Abstract
Neural crest (NC) is a vertebrate-specific embryonic progenitor cell population at the basis of important vertebrate features such as the craniofacial skeleton and pigmentation patterns. Despite the wide-ranging variation of NC-derived traits across vertebrates, the contribution of NC to species diversification remains underexplored. Here, leveraging the adaptive diversity of African Great Lakes' cichlid species, we combined comparative transcriptomics and population genomics to investigate the evolution of the NC genetic program in the context of their morphological divergence. Our analysis revealed substantial differences in transcriptional landscapes across somitogenesis, an embryonic period coinciding with NC development and migration. This included dozens of genes with described functions in the vertebrate NC gene regulatory network, several of which showed signatures of positive selection. Among candidates showing between-species expression divergence, we focused on teleost-specific paralogs of the NC-specifier sox10 (sox10a and sox10b) as prime candidates to influence NC development. These genes, expressed in NC cells, displayed remarkable spatio-temporal variation in cichlids, suggesting their contribution to interspecific morphological differences, such as craniofacial structures and pigmentation. Finally, through CRISPR/Cas9 mutagenesis, we demonstrated the functional divergence between cichlid sox10 paralogs, with the acquisition of a novel skeletogenic function by sox10a. When compared with teleost models zebrafish and medaka, our findings reveal that sox10 duplication, although retained in most teleost lineages, had variable functional fates across their phylogeny. Altogether, our study suggests that NC-related processes-particularly those controlled by sox10s-are involved in generating morphological diversification between species and lays the groundwork for further investigations into the mechanisms underpinning vertebrate NC diversification.
Collapse
Affiliation(s)
| | - Grégoire Vernaz
- Zoological Institute, University of Basel, Basel, Switzerland
| | | | - Maxon J Ngochera
- Malawi Fisheries Department, Senga Bay Fisheries Research Center, P.O. Box 316, Salima, Malawi
| | - Richard Durbin
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - M Emília Santos
- Department of Zoology, University of Cambridge, Cambridge, UK
| |
Collapse
|
2
|
Marconi A, Vernaz G, Karunaratna A, Ngochera MJ, Durbin R, Santos ME. Genetic and developmental divergence in the neural crest programme between cichlid fish species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.578004. [PMID: 38352436 PMCID: PMC10862805 DOI: 10.1101/2024.01.30.578004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Neural crest (NC) is a vertebrate-specific embryonic progenitor cell population at the basis of important vertebrate features such as the craniofacial skeleton and pigmentation patterns. Despite the wide-ranging variation of NC-derived traits across vertebrates, the contribution of NC to species diversification remains underexplored. Here, leveraging the adaptive diversity of African Great Lakes' cichlid species, we combined comparative transcriptomics and population genomics to investigate the evolution of the NC genetic programme in the context of their morphological divergence. Our analysis revealed substantial differences in transcriptional landscapes across somitogenesis, an embryonic period coinciding with NC development and migration. This included dozens of genes with described functions in the vertebrate NC gene regulatory network, several of which showed signatures of positive selection. Among candidates showing between-species expression divergence, we focused on teleost-specific paralogs of the NC-specifier sox10 (sox10a and sox10b) as prime candidates to influence NC development. These genes, expressed in NC cells, displayed remarkable spatio-temporal variation in cichlids, suggesting their contribution to inter-specific morphological differences. Finally, through CRISPR/Cas9 mutagenesis, we demonstrated the functional divergence between cichlid sox10 paralogs, with the acquisition of a novel skeletogenic function by sox10a. When compared to the teleost models zebrafish and medaka, our findings reveal that sox10 duplication, although retained in most teleost lineages, had variable functional fates across their phylogeny. Altogether, our study suggests that NC-related processes - particularly those controlled by sox10s - might be involved in generating morphological diversification between species and lays the groundwork for further investigations into mechanisms underpinning vertebrate NC diversification.
Collapse
Affiliation(s)
| | | | | | - Maxon J. Ngochera
- Senga Bay Fisheries Research Center, Malawi Fisheries Department, P.O. Box 316, Salima, Malawi
| | - Richard Durbin
- Department of Genetics, University of Cambridge, United Kingdom
| | | |
Collapse
|
3
|
Chen T, Jiao L, Ni L. The phylogeographical pattern of the Amur minnow Rhynchocypris lagowskii (Cypriniformes: Cyprinidae) in the Qinling Mountains. Ecol Evol 2022; 12:e8924. [PMID: 35600689 PMCID: PMC9108317 DOI: 10.1002/ece3.8924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 04/24/2022] [Accepted: 04/25/2022] [Indexed: 11/24/2022] Open
Abstract
In this study, the phylogeographical pattern of the Amur minnow (Rhynchocypris lagowskii) widely distributed in the cold freshwaters of the Qinling Mountains was examined. A total of 464 specimens from 48 localities were sequenced at a 540-bp region of the mitochondrial cytochrome b (Cytb) gene, and 69 haplotypes were obtained. The mean ratio of the number of synonymous and nonsynonymous substitutions per site (dN/dS) was 0.028 and indicated purifying selection. Haplotype diversity (h) and nucleotide diversity (π) of natural populations of R. lagowskii varied widely between distinct localities. Phylogenetic trees based on Bayesian inference (BI), maximum likelihood (ML), and maximum parsimony (MP) methods, and network analysis showed five well-differentiated lineages, but these did not completely correspond to localities and geographic distribution. Meanwhile, analysis of molecular variances (AMOVA) indicated the highest proportion of genetic variation was attributed to the differentiation between populations rather than by our defined lineages. In addition, there was no significant correlation between the pairwise Fst values and geographic distance (p > .05). Based on the molecular clock calibration, the time to the most recent common ancestor (TMRCA) was estimated to have emerged from the Late Miocene to the Early Pleistocene. Finally, the results of demographic history based on the neutrality test, mismatch distribution, and Bayesian skyline plot (BSP) analyses showed that collectively, the populations were stable during the Pleistocene while one lineage (lineage E) probably underwent a slight contraction during the Middle Pleistocene and a rapid expansion from the Middle to the Late Pleistocene. Therefore, the study suggests the current phylogeographical pattern of R. lagowskii was likely shaped by geological events that led to vicariance followed by dispersal and secondary contact, river capture, and climatic oscillation during the Late Miocene to the Early Pleistocene in the Qinling Mountains.
Collapse
Affiliation(s)
- Tao Chen
- Guangxi Key Laboratory of Diabetic Systems MedicineGuilin Medical UniversityGuilinP.R. China
- Faculty of Basic Medical SciencesGuilin Medical UniversityGuilinP.R. China
| | - Li Jiao
- College of Life SciencesShaanxi Normal UniversityXi’anP.R. China
| | - Lili Ni
- College of Life SciencesShaanxi Normal UniversityXi’anP.R. China
| |
Collapse
|
4
|
Diaz RE, Shylo NA, Roellig D, Bronner M, Trainor PA. Filling in the phylogenetic gaps: Induction, migration, and differentiation of neural crest cells in a squamate reptile, the veiled chameleon (Chamaeleo calyptratus). Dev Dyn 2019; 248:709-727. [DOI: 10.1002/dvdy.38] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 12/13/2022] Open
Affiliation(s)
- Raul E. Diaz
- Department of Biological Sciences, Southeastern Louisiana University Hammond Louisiana
- Natural History Museum of Los Angeles CountyDivision of Herpetology Los Angeles California
| | | | - Daniela Roellig
- Division of Biology and Biological Engineering, California Institute of Technology Pasadena California
| | - Marianne Bronner
- Division of Biology and Biological Engineering, California Institute of Technology Pasadena California
| | - Paul A. Trainor
- Stowers Institute for Medical Research Kansas City Missouri
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City Kansas
| |
Collapse
|
5
|
Whittle CA, Extavour CG. Contrasting patterns of molecular evolution in metazoan germ line genes. BMC Evol Biol 2019; 19:53. [PMID: 30744572 PMCID: PMC6371493 DOI: 10.1186/s12862-019-1363-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 01/14/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Germ lines are the cell lineages that give rise to the sperm and eggs in animals. The germ lines first arise from primordial germ cells (PGCs) during embryogenesis: these form from either a presumed derived mode of preformed germ plasm (inheritance) or from an ancestral mechanism of inductive cell-cell signalling (induction). Numerous genes involved in germ line specification and development have been identified and functionally studied. However, little is known about the molecular evolutionary dynamics of germ line genes in metazoan model systems. RESULTS Here, we studied the molecular evolution of germ line genes within three metazoan model systems. These include the genus Drosophila (N=34 genes, inheritance), the fellow insect Apis (N=30, induction), and their more distant relative Caenorhabditis (N=23, inheritance). Using multiple species and established phylogenies in each genus, we report that germ line genes exhibited marked variation in the constraint on protein sequence divergence (dN/dS) and codon usage bias (CUB) within each genus. Importantly, we found that de novo lineage-specific inheritance (LSI) genes in Drosophila (osk, pgc) and in Caenorhabditis (pie-1, pgl-1), which are essential to germ plasm functions under the derived inheritance mode, displayed rapid protein sequence divergence relative to the other germ line genes within each respective genus. We show this may reflect the evolution of specialized germ plasm functions and/or low pleiotropy of LSI genes, features not shared with other germ line genes. In addition, we observed that the relative ranking of dN/dS and of CUB between genera were each more strongly correlated between Drosophila and Caenorhabditis, from different phyla, than between Drosophila and its insect relative Apis, suggesting taxonomic differences in how germ line genes have evolved. CONCLUSIONS Taken together, the present results advance our understanding of the evolution of animal germ line genes within three well-known metazoan models. Further, the findings provide insights to the molecular evolution of germ line genes with respect to LSI status, pleiotropy, adaptive evolution as well as PGC-specification mode.
Collapse
Affiliation(s)
- Carrie A Whittle
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Cassandra G Extavour
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA.
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA.
| |
Collapse
|
6
|
Ahi EP, Sefc KM. Towards a gene regulatory network shaping the fins of the Princess cichlid. Sci Rep 2018; 8:9602. [PMID: 29942008 PMCID: PMC6018552 DOI: 10.1038/s41598-018-27977-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 06/01/2018] [Indexed: 02/08/2023] Open
Abstract
Variation in fin shape and size contributes to the outstanding morphological diversity of teleost fishes, but the regulation of fin growth has not yet been studied extensively outside the zebrafish model. A previous gene expression study addressing the ornamental elongations of unpaired fins in the African cichlid fish Neolamprologus brichardi identified three genes (cx43, mmp9 and sema3d) with strong and consistent expression differences between short and elongated fin regions. Remarkably, the expression patterns of these genes were not consistent with inferences on their regulatory interactions in zebrafish. Here, we identify a gene expression network (GRN) comprising cx43, mmp9, and possibly also sema3d by a stepwise approach of identifying co-expression modules and predicting their upstream regulators. Among the transcription factors (TFs) predicted as potential upstream regulators of 11 co-expressed genes, six TFs (foxc1, foxp1, foxd3, myc, egr2, irf8) showed expression patterns consistent with their cooperative transcriptional regulation of the gene network. Some of these TFs have already been implicated in teleost fish fin regeneration and formation. We particularly discuss the potential function of foxd3 as driver of the network and its role in the unexpected gene expression correlations observed in N. brichardi.
Collapse
Affiliation(s)
- Ehsan Pashay Ahi
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010, Graz, Austria.
| | - Kristina M Sefc
- Institute of Biology, University of Graz, Universitätsplatz 2, A-8010, Graz, Austria
| |
Collapse
|
7
|
Hall BK. Germ layers, the neural crest and emergent organization in development and evolution. Genesis 2018; 56:e23103. [PMID: 29637683 DOI: 10.1002/dvg.23103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 03/16/2018] [Accepted: 03/19/2018] [Indexed: 12/13/2022]
Abstract
Discovered in chick embryos by Wilhelm His in 1868 and named the neural crest by Arthur Milnes Marshall in 1879, the neural crest cells that arise from the neural folds have since been shown to differentiate into almost two dozen vertebrate cell types and to have played major roles in the evolution of such vertebrate features as bone, jaws, teeth, visceral (pharyngeal) arches, and sense organs. I discuss the discovery that ectodermal neural crest gave rise to mesenchyme and the controversy generated by that finding; the germ layer theory maintained that only mesoderm could give rise to mesenchyme. A second topic of discussion is germ layers (including the neural crest) as emergent levels of organization in animal development and evolution that facilitated major developmental and evolutionary change. The third topic is gene networks, gene co-option, and the evolution of gene-signaling pathways as key to developmental and evolutionary transitions associated with the origin and evolution of the neural crest and neural crest cells.
Collapse
Affiliation(s)
- Brian K Hall
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, B3H 2H8, Canada
| |
Collapse
|
8
|
Ahi EP, Richter F, Sefc KM. A gene expression study of ornamental fin shape in Neolamprologus brichardi, an African cichlid species. Sci Rep 2017; 7:17398. [PMID: 29234131 PMCID: PMC5727040 DOI: 10.1038/s41598-017-17778-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 11/29/2017] [Indexed: 01/14/2023] Open
Abstract
The diversity of fin morphology within and across fish taxa offers great, but still largely unexplored, opportunities to investigate the proximate mechanisms underlying fin shape variation. Relying on available genetic knowledge brought forth mainly by the comprehensive study of the zebrafish caudal fin, we explored candidate molecular mechanisms for the maintenance and formation of the conspicuously elongated filaments adorning the unpaired fins of the East African "princess cichlid" Neolamprologus brichardi. Via qPCR assays, we detected expression differences of candidate genes between elongated and short regions of intact and regenerating fins. The identified genes include skeletogenic and growth factors (igf2b, fgf3, bmp2 and bmp4), components of the WNT pathway (lef1, wnt5b and wnt10) and a regulatory network determining fin ray segment size and junction (cx43, esco2 and sema3d), as well as other genes with different roles (mmp9, msxb and pea3). Interestingly, some of these genes showed fin specific expression differences which are often neglected in studies of model fish that focus on the caudal fin. Moreover, while the observed expression patterns were generally consistent with zebrafish results, we also detected deviating expression correlations and gene functions.
Collapse
Affiliation(s)
- Ehsan Pashay Ahi
- Institute of Zoology, University of Graz, Universitätsplatz 2, A-8010, Graz, Austria.
| | | | | |
Collapse
|
9
|
Irie N. Remaining questions related to the hourglass model in vertebrate evolution. Curr Opin Genet Dev 2017; 45:103-107. [DOI: 10.1016/j.gde.2017.04.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 03/28/2017] [Accepted: 04/13/2017] [Indexed: 12/11/2022]
|