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Graham ZA, Padilla Perez DJ. Correlated evolution of conspicuous colouration and burrowing in crayfish. Proc Biol Sci 2024; 291:20240632. [PMID: 38981529 PMCID: PMC11335007 DOI: 10.1098/rspb.2024.0632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 05/02/2024] [Accepted: 06/14/2024] [Indexed: 07/11/2024] Open
Abstract
Conspicuous colours have fascinated biologists for centuries, leading to research on the evolution and functional significance of colour traits. In many cases, research suggests that conspicuous colours are adaptive and serve a function in sexual or aposematic signalling. In other cases, a lack of evidence for the adaptive value of conspicuous colours garners interest from biologists, such as when organisms that live underground and are rarely exposed to the surface are nevertheless colourful. Here, we use phylogenetic comparative methods to investigate colour evolution throughout freshwater crayfishes that vary in burrowing ability. Within the taxa we analysed, conspicuous colours have evolved independently over 50 times, and these colours are more common in semi-terrestrial crayfishes that construct extensive burrows. The intuitive but not evolutionarily justified assumption when presented with these results is to assume that these colours are adaptive. But contrary to this intuition, we discuss the hypothesis that colouration in crayfish is neutral. Supporting these ideas, the small population sizes and reduced gene flow within semi-terrestrial burrowing crayfishes may lead to the fixation of colour-phenotype mutations. Overall, our work brings into question the traditional view of animal colouration as a perfectly adapted phenotype.
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Affiliation(s)
- Zackary A. Graham
- Department of Organismal Biology, Ecology, and Zoo Science, West Liberty University, 208 University Drive, West Liberty, WV26074, USA
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2
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Recknagel H, Zakšek V, Delić T, Gorički Š, Trontelj P. Multiple transitions between realms shape relict lineages of Proteus cave salamanders. Mol Ecol 2024; 33:e16868. [PMID: 36715250 DOI: 10.1111/mec.16868] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/16/2023] [Indexed: 01/31/2023]
Abstract
In comparison to biodiversity on Earth's surface, subterranean biodiversity has largely remained concealed. The olm (Proteus anguinus) is one of the most enigmatic extant cave inhabitants, and until now little was known regarding its genetic structure and evolutionary history. Olms inhabit subterranean waters throughout the Dinaric Karst of the western Balkans, with a seemingly uniform phenotypic appearance of cave-specialized traits: an elongate body, snout and limbs, degenerated eyes and loss of pigmentation ("white olm"). Only a single small region in southeastern Slovenia harbours olms with a phenotype typical of surface animals: pigmented skin, eyes, a blunt snout and short limbs ("black olm"). We used a combination of mitochondrial DNA and genome-wide single nucleotide polymorphism data to investigate the molecular diversity, evolutionary history and biogeography of olms along the Dinaric Karst. We found nine deeply divergent species-level lineages that separated between 17 and 4 million years ago, while molecular diversity within lineages was low. We detected no signal of recent admixture between lineages and only limited historical gene flow. Biogeographically, the contemporaneous distribution of lineages mostly mirrors hydrologically separated subterranean environments, while the historical separation of olm lineages follows microtectonic and climatic changes in the area. The reconstructed phylogeny suggests at least four independent transitions to the cave phenotype. Two of the species-level lineages have miniscule ranges and may represent Europe's rarest amphibians. Their rarity and the decline in other lineages call for protection of their subterranean habitats.
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Affiliation(s)
- H Recknagel
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - V Zakšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - T Delić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Š Gorički
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Scriptorium biologorum, Murska Sobota, Slovenia
| | - P Trontelj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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3
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Xiao Y, Xiao Z, Liu L, Ma Y, Zhao H, Wu Y, Huang J, Xu P, Liu J, Li J. Innovative approach for high-throughput exploiting sex-specific markers in Japanese parrotfish Oplegnathus fasciatus. Gigascience 2024; 13:giae045. [PMID: 39028586 PMCID: PMC11258905 DOI: 10.1093/gigascience/giae045] [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: 12/06/2023] [Revised: 04/21/2024] [Accepted: 06/22/2024] [Indexed: 07/21/2024] Open
Abstract
BACKGROUND The use of sex-specific molecular markers has become a prominent method in enhancing fish production and economic value, as well as providing a foundation for understanding the complex molecular mechanisms involved in fish sex determination. Over the past decades, research on male and female sex identification has predominantly employed molecular biology methodologies such as restriction fragment length polymorphism, random amplification of polymorphic DNA, simple sequence repeat, and amplified fragment length polymorphism. The emergence of high-throughput sequencing technologies, particularly Illumina, has led to the utilization of single nucleotide polymorphism and insertion/deletion variants as significant molecular markers for investigating sex identification in fish. The advancement of sex-controlled breeding encounters numerous challenges, including the inefficiency of current methods, intricate experimental protocols, high costs of development, elevated rates of false positives, marker instability, and cumbersome field-testing procedures. Nevertheless, the emergence and swift progress of PacBio high-throughput sequencing technology, characterized by its long-read output capabilities, offers novel opportunities to overcome these obstacles. FINDINGS Utilizing male/female assembled genome information in conjunction with short-read sequencing data survey and long-read PacBio sequencing data, a catalog of large-segment (>100 bp) insertion/deletion genetic variants was generated through a genome-wide variant site-scanning approach with bidirectional comparisons. The sequence tagging sites were ranked based on the long-read depth of the insertion/deletion site, with markers exhibiting lower long-read depth being considered more effective for large-segment deletion variants. Subsequently, a catalog of bulk primers and simulated PCR for the male/female variant loci was developed, incorporating primer design for the target region and electronic PCR (e-PCR) technology. The Japanese parrotfish (Oplegnathus fasciatus), belonging to the Oplegnathidae family within the Centrarchiformes order, holds significant economic value as a rocky reef fish indigenous to East Asia. The criteria for rapid identification of male and female differences in Japanese parrotfish were established through agarose gel electrophoresis, which revealed 2 amplified bands for males and 1 amplified band for females. A high-throughput identification catalog of sex-specific markers was then constructed using this method, resulting in the identification of 3,639 (2,786 INS/853 DEL, ♀ as reference) and 3,672 (2,876 INS/833 DEL, ♂ as reference) markers in conjunction with 1,021 and 894 high-quality genetic sex identification markers, respectively. Sixteen differential loci were randomly chosen from the catalog for validation, with 11 of them meeting the criteria for male/female distinctions. The implementation of cost-effective and efficient technological processes would facilitate the rapid advancement of genetic breeding through expediting the high-throughput development of sex genetic markers for various species. CONCLUSIONS Our study utilized assembled genome information from male and female individuals obtained from PacBio, in addition to data from short-read sequencing data survey and long-read PacBio sequencing data. We extensively employed genome-wide variant site scanning and identification, high-throughput primer design of target regions, and e-PCR batch amplification, along with statistical analysis and ranking of the long-read depth of the variant sites. Through this integrated approach, we successfully compiled a catalog of large insertion/deletion sites (>100 bp) in both male and female Japanese parrotfish.
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Affiliation(s)
- Yongshuang Xiao
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Zhizhong Xiao
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Weihai Hao Huigan Marine Biotechnology Co., Weihai, 26449, China
| | - Lin Liu
- Wuhan Frasergen Bioinformatics Co., Ltd, East Lake High-Tech Zone, Wuhan, 430073, China
| | - Yuting Ma
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Haixia Zhao
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Yanduo Wu
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Jinwei Huang
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Pingrui Xu
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Jing Liu
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Jun Li
- Center for Ocean Mega-Science, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266071, China
- Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
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Swaminathan A, Xia F, Rohner N. From darkness to discovery: evolutionary, adaptive, and translational genetic insights from cavefish. Trends Genet 2024; 40:24-38. [PMID: 38707509 PMCID: PMC11068324 DOI: 10.1016/j.tig.2023.10.002] [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] [Indexed: 05/07/2024]
Abstract
How genotype determines phenotype is a well-explored question, but genotype-environment interactions and their heritable impact on phenotype over the course of evolution are not as thoroughly investigated. The fish Astyanax mexicanus, consisting of surface and cave ecotypes, is an ideal emerging model to study the genetic basis of adaptation to new environments. This model has permitted quantitative trait locus mapping and whole-genome comparisons to identify the genetic bases of traits such as albinism and insulin resistance and has helped to better understand fundamental evolutionary mechanisms. In this review, we summarize recent advances in A. mexicanus genetics and discuss their broader impact on the fields of adaptation and evolutionary genetics.
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Affiliation(s)
| | - Fanning Xia
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, MO, USA
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS, USA
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5
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Ponnimbaduge Perera P, Perez Guerra D, Riddle MR. The Mexican Tetra, Astyanax mexicanus, as a Model System in Cell and Developmental Biology. Annu Rev Cell Dev Biol 2023; 39:23-44. [PMID: 37437210 DOI: 10.1146/annurev-cellbio-012023-014003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Our understanding of cell and developmental biology has been greatly aided by a focus on a small number of model organisms. However, we are now in an era where techniques to investigate gene function can be applied across phyla, allowing scientists to explore the diversity and flexibility of developmental mechanisms and gain a deeper understanding of life. Researchers comparing the eyeless cave-adapted Mexican tetra, Astyanax mexicanus, with its river-dwelling counterpart are revealing how the development of the eyes, pigment, brain, cranium, blood, and digestive system evolves as animals adapt to new environments. Breakthroughs in our understanding of the genetic and developmental basis of regressive and constructive trait evolution have come from A. mexicanus research. They include understanding the types of mutations that alter traits, which cellular and developmental processes they affect, and how they lead to pleiotropy. We review recent progress in the field and highlight areas for future investigations that include evolution of sex differentiation, neural crest development, and metabolic regulation of embryogenesis.
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Affiliation(s)
| | | | - Misty R Riddle
- Department of Biology, University of Nevada, Reno, Nevada, USA;
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Brown AR, Comai K, Mannino D, McCullough H, Donekal Y, Meyers HC, Graves CW, Seidel HS. A community-science approach identifies genetic variants associated with three color morphs in ball pythons (Python regius). PLoS One 2022; 17:e0276376. [PMID: 36260636 PMCID: PMC9581371 DOI: 10.1371/journal.pone.0276376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 10/05/2022] [Indexed: 11/13/2022] Open
Abstract
Color morphs in ball pythons (Python regius) provide a unique and largely untapped resource for understanding the genetics of coloration in reptiles. Here we use a community-science approach to investigate the genetics of three color morphs affecting production of the pigment melanin. These morphs-Albino, Lavender Albino, and Ultramel-show a loss of melanin in the skin and eyes, ranging from severe (Albino) to moderate (Lavender Albino) to mild (Ultramel). To identify genetic variants causing each morph, we recruited shed skins of pet ball pythons via social media, extracted DNA from the skins, and searched for putative loss-of-function variants in homologs of genes controlling melanin production in other vertebrates. We report that the Albino morph is associated with missense and non-coding variants in the gene TYR. The Lavender Albino morph is associated with a deletion in the gene OCA2. The Ultramel morph is associated with a missense variant and a putative deletion in the gene TYRP1. Our study is one of the first to identify genetic variants associated with color morphs in ball pythons and shows that pet samples recruited from the community can provide a resource for genetic studies in this species.
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Affiliation(s)
- Autumn R. Brown
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Kaylee Comai
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Dominic Mannino
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Haily McCullough
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Yamini Donekal
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Hunter C. Meyers
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Chiron W. Graves
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
- * E-mail: (CWG); (HSS)
| | - Hannah S. Seidel
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
- * E-mail: (CWG); (HSS)
| | - The BIO306W Consortium
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
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7
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Wang C, Xu J, Kocher TD, Li M, Wang D. CRISPR knockouts of pmela and pmelb engineered a golden tilapia by regulating relative pigment cell abundance. J Hered 2022; 113:398-413. [PMID: 35385582 DOI: 10.1093/jhered/esac018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
Premelanosome protein (pmel) is a key gene for melanogenesis. Mutations in this gene are responsible for white plumage in chicken, but its role in pigmentation of fish remains to be demonstrated. In this study we found that most fishes have two pmel genes arising from the teleost-specific whole genome duplication. Both pmela and pmelb were expressed at high levels in the eyes and skin of Nile tilapia. We mutated both genes in tilapia using CRISPR/Cas9. Homozygous mutation of pmela resulted in yellowish body color with weak vertical bars and a hypo-pigmented retinal pigment epithelium (RPE) due to significantly reduced number and size of melanophores. In contrast, we observed an increased number and size of xanthophores in mutants compared to wild-type fish. Homozygous mutation of pmelb resulted in a similar, but milder phenotype than pmela-/- mutants. Double mutation of pmela and pmelb resulted in loss of additional melanophores compared to the pmela-/- mutants, and also an increase in the number and size of xanthophores, producing a golden body color. The RPE pigmentation of pmela-/-;pmelb-/- was similar to pmela-/- mutants, with much less pigmentation than pmelb-/- mutants and wild-type fish. Taken together, our results indicate that, while both pmel genes are important for the formation of body color in tilapia, pmela plays a more important role than pmelb. To our knowledge, this is the first report on mutation of pmelb or both pmela;pmelb in fish. Studies on these mutants suggest new strategies for breeding golden tilapia, and also provide a new model for studies of pmel function in vertebrates.
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Affiliation(s)
- Chenxu Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Jia Xu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Thomas D Kocher
- Department of Biology, University of Maryland College Park, Maryland, USA
| | - Minghui Li
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Deshou Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
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8
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O'Gorman M, Thakur S, Imrie G, Moran RL, Choy S, Sifuentes-Romero I, Bilandžija H, Renner KJ, Duboué E, Rohner N, McGaugh SE, Keene AC, Kowalko JE. Pleiotropic function of the oca2 gene underlies the evolution of sleep loss and albinism in cavefish. Curr Biol 2021; 31:3694-3701.e4. [PMID: 34293332 DOI: 10.1016/j.cub.2021.06.077] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 03/22/2021] [Accepted: 06/25/2021] [Indexed: 12/29/2022]
Abstract
Adaptation to novel environments often involves the evolution of multiple morphological, physiological, and behavioral traits. One striking example of multi-trait evolution is the suite of traits that has evolved repeatedly in cave animals, including regression of eyes, loss of pigmentation, and enhancement of non-visual sensory systems.1,2 The Mexican tetra, Astyanax mexicanus, consists of fish that inhabit at least 30 caves in Mexico and ancestral-like surface fish that inhabit the rivers of Mexico and southern Texas.3 Cave A. mexicanus are interfertile with surface fish and have evolved a number of traits, including reduced pigmentation, eye loss, and alterations to behavior.4-6 To define relationships between different cave-evolved traits, we phenotyped 208 surface-cave F2 hybrid fish for numerous morphological and behavioral traits. We found differences in sleep between pigmented and albino hybrid fish, raising the possibility that these traits share a genetic basis. In cavefish and other species, mutations in oculocutaneous albinism 2 (oca2) cause albinism.7-12 Surface fish with mutations in oca2 displayed both albinism and reduced sleep. Further, this mutation in oca2 fails to complement sleep loss when surface fish harboring this engineered mutation are crossed to independently evolved populations of albino cavefish with naturally occurring mutations in oca2. Analysis of the oca2 locus in wild-caught cave and surface fish suggests that oca2 is under positive selection in 3 cave populations. Taken together, these findings identify oca2 as a novel regulator of sleep and suggest that a pleiotropic function of oca2 underlies the adaptive evolution of albinism and sleep loss.
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Affiliation(s)
- Morgan O'Gorman
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Sunishka Thakur
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Gillian Imrie
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Rachel L Moran
- Department of Ecology, Evolution, and Behavior. University of Minnesota, St. Paul, MN 55108, USA
| | - Stefan Choy
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | | | - Helena Bilandžija
- Department of Molecular Biology, Rudjer Boskovic Institute, 10000 Zagreb, Croatia
| | - Kenneth J Renner
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Erik Duboué
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | | | - Suzanne E McGaugh
- Department of Ecology, Evolution, and Behavior. University of Minnesota, St. Paul, MN 55108, USA
| | - Alex C Keene
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Biology Science, Florida Atlantic University, Jupiter, FL 33458, USA.
| | - Johanna E Kowalko
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA.
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9
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Parichy DM. Evolution of pigment cells and patterns: recent insights from teleost fishes. Curr Opin Genet Dev 2021; 69:88-96. [PMID: 33743392 DOI: 10.1016/j.gde.2021.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/04/2021] [Accepted: 02/09/2021] [Indexed: 01/08/2023]
Abstract
Skin pigment patterns of vertebrates are stunningly diverse, and nowhere more so than in teleost fishes. Several species, including relatives of zebrafish, recently evolved cichlid fishes of East Africa, clownfishes, deep sea fishes, and others are providing insights into pigment pattern evolution. This overview describes recent advances in understanding periodic patterns, like stripes and spots, the loss of patterns, and the role of cell-type diversification in generating pigmentation phenotypes. Advances in this area are being facilitated by the application of modern methods of gene editing, genomics, computational analysis, and other approaches to non-traditional model organisms having interesting pigmentary phenotypes. Several topics worthy of future attention are outlined as well.
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Affiliation(s)
- David M Parichy
- Department of Biology, Department of Cell Biology, University of Virginia, Charlottesville, VA 22903, United States.
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10
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Zhao Y, Chen H, Li C, Chen S, Xiao H. Comparative Transcriptomics Reveals the Molecular Genetic Basis of Cave Adaptability in Sinocyclocheilus Fish Species. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.589039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cavefish evolved a series of distinct survival mechanisms for adaptation to cave habitat. Such mechanisms include loss of eyesight and pigmentation, sensitive sensory organs, unique dietary preferences, and predation behavior. Thus, it is of great interest to understand the mechanisms underlying these adaptability traits of troglobites. The teleost genus Sinocyclocheilus (Cypriniformes: Cyprinidae) is endemic to China and has more than 70 species reported (including over 30 cavefish species). High species diversity and diverse phenotypes make the Sinocyclocheilus as an outstanding model for studying speciation and adaptive evolution. In this study, we conducted a comparative transcriptomics study on the brain tissues of two Sinocyclocheilus species (surface-dwelling species – Sinocyclocheilus malacopterus and semi-cave-dwelling species – Sinocyclocheilus rhinocerous living in the same water body. A total of 425,188,768 clean reads were generated, which contributed to 102,839 Unigenes. Bioinformatic analysis revealed a total of 3,289 differentially expressed genes (DEGs) between two species Comparing to S. malacopterus, 2,598 and 691 DEGs were found to be respectively, down-regulated and up-regulated in S. rhinocerous. Furthermore, it is also found tens of DEGs related to cave adaptability such as insulin secretion regulation (MafA, MafB, MafK, BRSK, and CDK16) and troglomorphic traits formation (CEP290, nmnat1, coasy, and pqbp1) in the cave-dwelling S. rhinocerous. Interestingly, most of the DEGs were found to be down-regulated in cavefish species and this trend of DEGs expression was confirmed through qPCR experiments. This study would provide an appropriate genetic basis for future studies on the formation of troglomorphic traits and adaptability characters of troglobites, and improve our understanding of mechanisms of cave adaptation.
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Abstract
AbstractBiologists usually pursue the adaptationist paradigm in trying to explain the functional significance of animal coloration. Here I collate instances in which coloration may be a poor match in the context of background matching, Batesian mimicry, aposematism, and colour polymorphisms. This can occur because of trade-offs with other functions, relaxed selection from predation, or colour trait neutrality. Also, mechanistic, pleiotropic and chance genetic effects can all result in a poor match to the background environment or to signaling efficiently. While biologists implicitly recognise these constraints placed on adaptive coloration, they rarely explicitly acknowledge the heterodox notion that coloration might be under weak selection or no selection at all. Unfortunately, it is difficult to show this definitively, as illustrated in an investigation into the function of colour polymorphisms in coconut crabs.
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12
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Aardema ML, Stiassny MLJ, Alter SE. Genomic Analysis of the Only Blind Cichlid Reveals Extensive Inactivation in Eye and Pigment Formation Genes. Genome Biol Evol 2020; 12:1392-1406. [PMID: 32653909 PMCID: PMC7502198 DOI: 10.1093/gbe/evaa144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2020] [Indexed: 12/21/2022] Open
Abstract
Trait loss represents an intriguing evolutionary problem, particularly when it occurs across independent lineages. Fishes in light-poor environments often evolve “troglomorphic” traits, including reduction or loss of both pigment and eyes. Here, we investigate the genomic basis of trait loss in a blind and depigmented African cichlid, Lamprologus lethops, and explore evolutionary forces (selection and drift) that may have contributed to these losses. This species, the only known blind cichlid, is endemic to the lower Congo River. Available evidence suggests that it inhabits deep, low-light habitats. Using genome sequencing, we show that genes related to eye formation and pigmentation, as well as other traits associated with troglomorphism, accumulated inactivating mutations rapidly after speciation. A number of the genes affected in L. lethops are also implicated in troglomorphic phenotypes in Mexican cavefish (Astyanax mexicanus) and other species. Analysis of heterozygosity patterns across the genome indicates that L. lethops underwent a significant population bottleneck roughly 1 Ma, after which effective population sizes remained low. Branch-length tests on a subset of genes with inactivating mutations show little evidence of directional selection; however, low overall heterozygosity may reduce statistical power to detect such signals. Overall, genome-wide patterns suggest that accelerated genetic drift from a severe bottleneck, perhaps aided by directional selection for the loss of physiologically expensive traits, caused inactivating mutations to fix rapidly in this species.
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Affiliation(s)
- Matthew L Aardema
- Department of Biology, Montclair State University.,Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York
| | - Melanie L J Stiassny
- Department of Ichthyology, American Museum of Natural History, New York, New York
| | - S Elizabeth Alter
- Department of Ichthyology, American Museum of Natural History, New York, New York.,The Graduate Center, City University of New York.,Department of Biology, York College/The City University of New York
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13
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Zhang J, Qi J, Shi F, Pan H, Liu M, Tian R, Geng Y, Li H, Qu Y, Chen J, Seim I, Li M. Insights into the Evolution of Neoteny from the Genome of the Asian Icefish Protosalanx chinensis. iScience 2020; 23:101267. [PMID: 32593955 PMCID: PMC7327861 DOI: 10.1016/j.isci.2020.101267] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/28/2020] [Accepted: 06/08/2020] [Indexed: 12/23/2022] Open
Abstract
Salangids, known as Asian icefishes, represent a peculiar radiation within the bony fish order Protacanthopterygii where adult fish retain larval characteristics such as transparent and miniaturized bodies and a cartilaginous endoskeleton into adulthood. Here, we report a de novo genome of Protosalanx chinensis, the most widely distributed salangid lineage. The P. chinensis genome assembly is more contiguous and complete than a previous assembly. We estimate that P. chinensis, salmons, trouts, and pikes diverged from a common ancestor 185 million years ago. A juxtaposition with other fish genomes revealed loss of the genes encoding ectodysplasin-A receptor (EDAR), SCPP1, and four Hox proteins and likely lack of canonical fibroblast growth factor 5 (FGF5) function. We also report genomic variations of P. chinensis possibly reflecting the immune system repertoire of a species with a larval phenotype in sexually mature individuals. The new Asian icefish reference genome provides a solid foundation for future studies.
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Affiliation(s)
- Jie Zhang
- Chinese Academy of Sciences Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.
| | - Jiwei Qi
- Chinese Academy of Sciences Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China
| | - Fanglei Shi
- Chinese Academy of Sciences Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huijuan Pan
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Meng Liu
- Novogene Bioinformatics Institute, Beijing 100083, China
| | - Ran Tian
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China
| | - Yuepan Geng
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China
| | - Huaying Li
- Novogene Bioinformatics Institute, Beijing 100083, China
| | - Yujie Qu
- Novogene Bioinformatics Institute, Beijing 100083, China
| | - Jinping Chen
- Guangdong Key Laboratory of Animal Conservation and Resource, Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangdong Institute of Applied Biological Resources, Guangzhou 510260, China.
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China; Comparative and Endocrine Biology Laboratory, Translational Research Institute-Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Woolloongabba, QLD 4102, Australia.
| | - Ming Li
- Chinese Academy of Sciences Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China.
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14
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Developmental Transcriptomic Analysis of the Cave-Dwelling Crustacean, Asellus aquaticus. Genes (Basel) 2019; 11:genes11010042. [PMID: 31905778 PMCID: PMC7016750 DOI: 10.3390/genes11010042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/16/2019] [Accepted: 12/22/2019] [Indexed: 12/18/2022] Open
Abstract
Cave animals are a fascinating group of species often demonstrating characteristics including reduced eyes and pigmentation, metabolic efficiency, and enhanced sensory systems. Asellus aquaticus, an isopod crustacean, is an emerging model for cave biology. Cave and surface forms of this species differ in many characteristics, including eye size, pigmentation, and antennal length. Existing resources for this species include a linkage map, mapped regions responsible for eye and pigmentation traits, sequenced adult transcriptomes, and comparative embryological descriptions of the surface and cave forms. Our ultimate goal is to identify genes and mutations responsible for the differences between the cave and surface forms. To advance this goal, we decided to use a transcriptomic approach. Because many of these changes first appear during embryonic development, we sequenced embryonic transcriptomes of cave, surface, and hybrid individuals at the stage when eyes and pigment become evident in the surface form. We generated a cave, a surface, a hybrid, and an integrated transcriptome to identify differentially expressed genes in the cave and surface forms. Additionally, we identified genes with allele-specific expression in hybrid individuals. These embryonic transcriptomes are an important resource to assist in our ultimate goal of determining the genetic underpinnings of the divergence between the cave and surface forms.
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15
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Liu Z, Wen H, Hailer F, Dong F, Yang Z, Liu T, Han L, Shi F, Hu Y, Zhou J. Pseudogenization of
Mc1r
gene associated with transcriptional changes related to melanogenesis explains leucistic phenotypes in
Oreonectes
cavefish (Cypriniformes, Nemacheilidae). J ZOOL SYST EVOL RES 2019. [DOI: 10.1111/jzs.12286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhijin Liu
- State Key Laboratory Cultivation for Karst Mountain Ecology Environment of Guizhou ProvinceGuizhou Normal University Guiyang Guizhou China
- CAS Key Laboratory of Animal Ecology and Conservation BiologyInstitute of Zoology Chaoyang District Beijing China
| | - Huamei Wen
- State Key Laboratory Cultivation for Karst Mountain Ecology Environment of Guizhou ProvinceGuizhou Normal University Guiyang Guizhou China
| | - Frank Hailer
- School of BiosciencesCardiff University Cardiff UK
| | - Fang Dong
- CAS Key Laboratory of Animal Ecology and Conservation BiologyInstitute of Zoology Chaoyang District Beijing China
- Institute of Physical Science and Information TechnologyAnhui University Hefei Anhui China
| | - Zuomin Yang
- School of Life SciencesQufu Normal University Qufu Shandong China
| | - Tao Liu
- State Key Laboratory Cultivation for Karst Mountain Ecology Environment of Guizhou ProvinceGuizhou Normal University Guiyang Guizhou China
| | - Ling Han
- State Key Laboratory Cultivation for Karst Mountain Ecology Environment of Guizhou ProvinceGuizhou Normal University Guiyang Guizhou China
| | - Fanglei Shi
- CAS Key Laboratory of Animal Ecology and Conservation BiologyInstitute of Zoology Chaoyang District Beijing China
| | - Yibo Hu
- CAS Key Laboratory of Animal Ecology and Conservation BiologyInstitute of Zoology Chaoyang District Beijing China
| | - Jiang Zhou
- State Key Laboratory Cultivation for Karst Mountain Ecology Environment of Guizhou ProvinceGuizhou Normal University Guiyang Guizhou China
- CAS Key Laboratory of Animal Ecology and Conservation BiologyInstitute of Zoology Chaoyang District Beijing China
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16
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Soares D, Niemiller ML. Extreme Adaptation in Caves. Anat Rec (Hoboken) 2018; 303:15-23. [PMID: 30537183 DOI: 10.1002/ar.24044] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 04/17/2018] [Accepted: 05/03/2018] [Indexed: 12/31/2022]
Abstract
Cave adaptation leads to unique anatomical specializations in many taxonomic groups. As the role of vision is reduced or disappears in a subterranean environment, other specializations arise to allow the organism to successfully detect and interact with their environment. A suite of unique, convergent phenotypes associated with subterranean adaptation has emerged (termed troglomorphy), with reduction or loss of pigmentation and eyes being the most conspicuous. Two vertebrate groups that have successfully colonized and adapted to subterranean environments are cavefishes and cave salamanders. There are many shared troglomorphic anatomical characters shared between these two groups, and we describe herein the morphological traits that are unique to fishes and salamanders that are adapted to caves and other subterranean habitats. Troglobionts, animals strictly bound and adapted to underground habitats, are outcomes of not just regressive evolution, but also constructive adaptation. There are skeletal changes, such as broadening and flattening of the head, as well as hypertrophy of non-visual modalities. Cavefishes and salamanders have lost eyes and pigmentation, but also enhanced mechanosenzation, chemosenzation and, in some cases, electroreception. Both cavefishes and cave salamanders have become important models in the study of the ecology, behavior, and evolution of subterranean colonization and adaptation. However, our knowledge is primarily limited to a few taxa and many questions remain to be studied. Anat Rec, 2018. © 2018 American Association for Anatomy.
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Affiliation(s)
- Daphne Soares
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Matthew L Niemiller
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, Alabama
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17
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Herman A, Brandvain Y, Weagley J, Jeffery WR, Keene AC, Kono TJY, Bilandžija H, Borowsky R, Espinasa L, O'Quin K, Ornelas-García CP, Yoshizawa M, Carlson B, Maldonado E, Gross JB, Cartwright RA, Rohner N, Warren WC, McGaugh SE. The role of gene flow in rapid and repeated evolution of cave-related traits in Mexican tetra, Astyanax mexicanus. Mol Ecol 2018; 27:4397-4416. [PMID: 30252986 PMCID: PMC6261294 DOI: 10.1111/mec.14877] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/08/2018] [Accepted: 08/19/2018] [Indexed: 12/13/2022]
Abstract
Understanding the molecular basis of repeatedly evolved phenotypes can yield key insights into the evolutionary process. Quantifying gene flow between populations is especially important in interpreting mechanisms of repeated phenotypic evolution, and genomic analyses have revealed that admixture occurs more frequently between diverging lineages than previously thought. In this study, we resequenced 47 whole genomes of the Mexican tetra from three cave populations, two surface populations and outgroup samples. We confirmed that cave populations are polyphyletic and two Astyanax mexicanus lineages are present in our data set. The two lineages likely diverged much more recently than previous mitochondrial estimates of 5-7 mya. Divergence of cave populations from their phylogenetically closest surface population likely occurred between ~161 and 191 k generations ago. The favoured demographic model for most population pairs accounts for divergence with secondary contact and heterogeneous gene flow across the genome, and we rigorously identified gene flow among all lineages sampled. Therefore, the evolution of cave-related traits occurred more rapidly than previously thought, and trogolomorphic traits are maintained despite gene flow with surface populations. The recency of these estimated divergence events suggests that selection may drive the evolution of cave-derived traits, as opposed to disuse and drift. Finally, we show that a key trogolomorphic phenotype QTL is enriched for genomic regions with low divergence between caves, suggesting that regions important for cave phenotypes may be transferred between caves via gene flow. Our study shows that gene flow must be considered in studies of independent, repeated trait evolution.
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Affiliation(s)
- Adam Herman
- Plant and Microbial Biology, Gortner Lab, University of Minnesota, Saint Paul, Minnesota
- Department of Molecular Biology, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Yaniv Brandvain
- Plant and Microbial Biology, Gortner Lab, University of Minnesota, Saint Paul, Minnesota
| | - James Weagley
- Ecology, Evolution, and Behavior, Gortner Lab, University of Minnesota, Saint Paul, Minnesota
| | - William R Jeffery
- Department of Biology, University of Maryland, College Park, Maryland
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
| | - Thomas J Y Kono
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota
| | - Helena Bilandžija
- Department of Molecular Biology, Rudjer Boskovic Institute, Zagreb, Croatia
- Department of Biology, University of Maryland, College Park, Maryland
| | | | - Luis Espinasa
- School of Science, Marist College, Poughkeepsie, New York
| | - Kelly O'Quin
- Department of Biology, Centre College, Danville, Kentucky
| | - Claudia P Ornelas-García
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Coyoacán, Mexico
| | - Masato Yoshizawa
- Department of Biology, University of Hawai'i at Mānoa, Honolulu, Hawaii
| | - Brian Carlson
- Department of Biology, College of Wooster, Wooster, Ohio
| | - Ernesto Maldonado
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Joshua B Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
| | - Reed A Cartwright
- The Biodesign Institute, Arizona State University, Tempe, Arizona
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, Missouri
- Department of Molecular and Integrative Physiology, The University of Kansas Medical Center, Kansas City, Kansas
| | - Wesley C Warren
- McDonnell Genome Institute, Washington University, St Louis, Missouri
| | - Suzanne E McGaugh
- Department of Molecular Biology, Rudjer Boskovic Institute, Zagreb, Croatia
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18
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Re C, Fišer Ž, Perez J, Tacdol A, Trontelj P, Protas ME. Common Genetic Basis of Eye and Pigment Loss in Two Distinct Cave Populations of the Isopod Crustacean Asellus aquaticus. Integr Comp Biol 2018; 58:421-430. [DOI: 10.1093/icb/icy028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Cassandra Re
- Dominican University of California, 50 Acacia Avenue, San Rafael, CA 94901, USA
| | - Žiga Fišer
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana SI-1000, Slovenia
| | - Justin Perez
- Dominican University of California, 50 Acacia Avenue, San Rafael, CA 94901, USA
| | - Allyson Tacdol
- Dominican University of California, 50 Acacia Avenue, San Rafael, CA 94901, USA
| | - Peter Trontelj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana SI-1000, Slovenia
| | - Meredith E Protas
- Dominican University of California, 50 Acacia Avenue, San Rafael, CA 94901, USA
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19
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Jaggard JB, Stahl BA, Lloyd E, Prober DA, Duboue ER, Keene AC. Hypocretin underlies the evolution of sleep loss in the Mexican cavefish. eLife 2018; 7:32637. [PMID: 29405117 PMCID: PMC5800846 DOI: 10.7554/elife.32637] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/25/2017] [Indexed: 01/09/2023] Open
Abstract
The duration of sleep varies dramatically between species, yet little is known about the genetic basis or evolutionary factors driving this variation in behavior. The Mexican cavefish, Astyanax mexicanus, exists as surface populations that inhabit rivers, and multiple cave populations with convergent evolution on sleep loss. The number of Hypocretin/Orexin (HCRT)-positive hypothalamic neurons is increased significantly in cavefish, and HCRT is upregulated at both the transcript and protein levels. Pharmacological or genetic inhibition of HCRT signaling increases sleep in cavefish, suggesting enhanced HCRT signaling underlies the evolution of sleep loss. Ablation of the lateral line or starvation, manipulations that selectively promote sleep in cavefish, inhibit hcrt expression in cavefish while having little effect on surface fish. These findings provide the first evidence of genetic and neuronal changes that contribute to the evolution of sleep loss, and support a conserved role for HCRT in sleep regulation.
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Affiliation(s)
- James B Jaggard
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
| | - Bethany A Stahl
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
| | - Evan Lloyd
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
| | - David A Prober
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Erik R Duboue
- Department of Embryology, Carnegie Institution for Science, Baltimore, United States.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, United States
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
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20
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Jaggard J, Robinson BG, Stahl BA, Oh I, Masek P, Yoshizawa M, Keene AC. The lateral line confers evolutionarily derived sleep loss in the Mexican cavefish. ACTA ACUST UNITED AC 2017; 220:284-293. [PMID: 28100806 DOI: 10.1242/jeb.145128] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/23/2016] [Indexed: 01/19/2023]
Abstract
Sleep is an essential behavior exhibited by nearly all animals, and disruption of this process is associated with an array of physiological and behavioral deficits. Sleep is defined by changes in sensory gating that reduce sensory input to the brain, but little is known about the neural basis for interactions between sleep and sensory processing. Blind Mexican cavefish comprise an extant surface dwelling form and 29 cave morphs that have independently evolved increased numbers of mechanoreceptive lateral line neuromasts and convergent evolution of sleep loss. Ablation of the lateral line enhanced sleep in the Pachón cavefish population, suggesting that heightened sensory input underlies evolutionarily derived sleep loss. Targeted lateral line ablation and behavioral analysis localized the wake-promoting neuromasts in Pachón cavefish to superficial neuromasts of the trunk and cranial regions. Strikingly, lateral line ablation did not affect sleep in four other cavefish populations, suggesting that distinct neural mechanisms regulate the evolution of sleep loss in independently derived cavefish populations. Cavefish are subject to seasonal changes in food availability, raising the possibility that sensory modulation of sleep is influenced by metabolic state. We found that starvation promotes sleep in Pachón cavefish, and is not enhanced by lateral line ablation, suggesting that functional interactions occur between sensory and metabolic regulation of sleep. Taken together, these findings support a model where sensory processing contributes to evolutionarily derived changes in sleep that are modulated in accordance with food availability.
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Affiliation(s)
- James Jaggard
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Beatriz G Robinson
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Bethany A Stahl
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Ian Oh
- Davidson Academy of Nevada, Reno, NV 89557, USA
| | - Pavel Masek
- Department of Biology, SUNY Binghamton, Binghamton, NY 13902, USA
| | - Masato Yoshizawa
- Department of Biology, University of Hawaii, Manoa, Honolulu, HI 96822, USA
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
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21
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Xu T, Deng H, Zhou J. The Cavefish Oreonectes jiarongensis can be Induced to Differentiate and Recover under the Light Condition. TRANSYLVANIAN REVIEW OF SYSTEMATICAL AND ECOLOGICAL RESEARCH 2017. [DOI: 10.1515/trser-2017-0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
This research indicated that one cave fish species of Oreonectes jiarongensis can recover the transparent to black under the light condition, this species belongs to the Oreonectes, Nemacheilinae, and distributes in Libo County, Guizhou Province, China. The changing process time was 14 days. This is the first time that suggests the cave vertebrates which lived in the dark environment not longer time could change the body color in the light environment, and has a new adaptive strategy for the darkness condition. The result may indicate that this species entrance the underground river not so long time, and the genes not mutation, which control the melanin express, it still has the physiological regulation mechanism under the light condition.
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Affiliation(s)
- Tielong Xu
- School of Life Sciences-Guizhou Normal University , Yunyan District, Baoshan Beilu Street 116, Guiyang , China , CN-550001
| | - Huaiqing Deng
- School of Life Sciences-Guizhou Normal University , Yunyan District, Baoshan Beilu Street 116, Guiyang , China , CN-550001
| | - Jiang Zhou
- School of Life Sciences-Guizhou Normal University , Yunyan District, Baoshan Beilu Street 116, Guiyang , China , CN-550001
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22
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Stahl BA, Gross JB. A Comparative Transcriptomic Analysis of Development in Two Astyanax Cavefish Populations. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2017; 328:515-532. [PMID: 28612405 DOI: 10.1002/jez.b.22749] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/24/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022]
Abstract
Organisms that are isolated into extreme environments often evolve extreme phenotypes. However, global patterns of dynamic gene expression changes that accompany dramatic environmental changes remain largely unknown. The blind Mexican cavefish, Astyanax mexicanus, has evolved a number of severe cave-associated phenotypes including loss of vision and pigmentation, craniofacial bone fusions, increased fat storage, reduced sleep, and amplified nonvisual sensory systems. Interestingly, surface-dwelling forms have repeatedly entered different caves throughout Mexico, providing a natural set of "replicate" instances of cave isolation. These surrogate "ancestral" surface-dwelling forms persist in nearby rivers, enabling direct comparisons to the "derived" cave-dwelling form. We evaluated changes associated with subterranean isolation by measuring differential gene expression in two geographically distinct cave-dwelling populations (Pachón and Tinaja). To understand the impact of these expression changes on development, we performed RNA-sequencing across four critical stages during which troglomorphic traits first appear in cavefish embryos. Gene ontology (GO) studies revealed similar functional profiles evolved in both independent cave lineages. However, enrichment studies indicated that similar GO profiles were occasionally mediated by different genes. Certain "master" regulators, such as Otx2 and Mitf, appear to be important loci for cave adaptation, as remarkably similar patterns of expression were identified in both independent cave lineages. This work reveals that adaptation to an extreme environment, in two distinct cavefish lineages, evolves through a combination of unique and shared gene expression patterns. Shared expression profiles reflect common environmental pressures, while unique expression likely reflects the fact that similar adaptive traits evolve through diverse genetic mechanisms.
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Affiliation(s)
- Bethany A Stahl
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
| | - Joshua B Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
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23
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Ligon RA, Simpson RK, Mason NA, Hill GE, McGraw KJ. Evolutionary innovation and diversification of carotenoid‐based pigmentation in finches. Evolution 2016; 70:2839-2852. [DOI: 10.1111/evo.13093] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/03/2016] [Accepted: 10/08/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Russell A. Ligon
- School of Life Sciences Arizona State University Tempe Arizona 85287
- Laboratory of Ornithology Cornell University Ithaca New York 14850
| | | | - Nicholas A. Mason
- Laboratory of Ornithology Cornell University Ithaca New York 14850
- Department of Ecology and Evolutionary Biology Cornell University Ithaca New York 14853
| | - Geoffrey E. Hill
- Department of Biological Sciences Auburn University Auburn Alabama 36849
| | - Kevin J. McGraw
- School of Life Sciences Arizona State University Tempe Arizona 85287
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24
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Genetic Convergence in the Evolution of Male-Specific Color Patterns in Drosophila. Curr Biol 2016; 26:2423-2433. [DOI: 10.1016/j.cub.2016.07.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/10/2016] [Accepted: 07/13/2016] [Indexed: 11/23/2022]
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25
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Gross JB, Powers AK, Davis EM, Kaplan SA. A pleiotropic interaction between vision loss and hypermelanism in Astyanax mexicanus cave x surface hybrids. BMC Evol Biol 2016; 16:145. [PMID: 27363593 PMCID: PMC4929771 DOI: 10.1186/s12862-016-0716-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/28/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Cave-dwelling animals evolve various traits as a consequence of life in darkness. Constructive traits (e.g., enhanced non-visual sensory systems) presumably arise under strong selective pressures. The mechanism(s) driving regression of features, however, are not well understood. Quantitative trait locus (QTL) analyses in Astyanax mexicanus Pachón cave x surface hybrids revealed phenotypic effects associated with vision and pigmentation loss. Vision QTL were uniformly associated with reductions in the homozygous cave condition, however pigmentation QTL demonstrated mixed phenotypic effects. This implied pigmentation might be lost through both selective and neutral forces. Alternatively, in this report, we examined if a pleiotropic interaction may exist between vision and pigmentation since vision loss has been shown to result in darker skin in other fish and amphibian model systems. RESULTS We discovered that certain members of Pachón x surface pedigrees are significantly darker than surface-dwelling fish. All of these "hypermelanic" individuals demonstrated severe visual system malformations suggesting they may be blind. A vision-mediated behavioral assay revealed that these fish, in stark contrast to surface fish, behaved the same as blind cavefish. Further, hypermelanic melanophores were larger and more dendritic in morphology compared to surface fish melanophores. However, hypermelanic melanophores responded normally to melanin-concentrating hormone suggesting darkening stemmed from vision loss, rather than a defect in pigment cell function. Finally, a number of genomic regions were coordinately associated with both reduced vision and increased pigmentation. CONCLUSIONS This work suggests hypermelanism in hybrid Astyanax results from blindness. This finding provides an alternative explanation for phenotypic effect studies of pigmentation QTL as stemming (at least in part) from environmental, rather than exclusively genetic, interactions between two regressive phenotypes. Further, this analysis reveals persistence of background adaptation in Astyanax. As the eye was lost in cave-dwelling forms, enhanced pigmentation resulted. Given the extreme cave environment, which is often devoid of nutrition, enhanced pigmentation may impose an energetic cost. Such an energetic cost would be selected against, as a means of energy conservation. Thus, the pleiotropic interaction between vision loss and pigmentation may reveal an additional selective pressure favoring the loss of pigmentation in cave-dwelling animals.
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Affiliation(s)
- Joshua B. Gross
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
- />Department of Biological Sciences, University of Cincinnati, Rieveschl Hall Room 711B, 312 Clifton Court, Cincinnati, Ohio 45221 USA
| | - Amanda K. Powers
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
| | - Erin M. Davis
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
| | - Shane A. Kaplan
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
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Wilkens H. Genetics and hybridization in surface and caveAstyanax(Teleostei): a comparison of regressive and constructive traits. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12773] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Horst Wilkens
- University of Hamburg; Centrum für Naturkunde - CeNak; Zoological Museum; Martin-Luther-King-Platz 3 20146 Hamburg Germany
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Gross JB, Stahl BA, Powers AK, Carlson BM. Natural bone fragmentation in the blind cave-dwelling fish, Astyanax mexicanus: candidate gene identification through integrative comparative genomics. Evol Dev 2016; 18:7-18. [PMID: 26153732 PMCID: PMC5226847 DOI: 10.1111/ede.12131] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Animals that colonize dark and nutrient-poor subterranean environments evolve numerous extreme phenotypes. These include dramatic changes to the craniofacial complex, many of which are under genetic control. These phenotypes can demonstrate asymmetric genetic signals wherein a QTL is detected on one side of the face but not the other. The causative gene(s) underlying QTL are difficult to identify with limited genomic resources. We approached this task by searching for candidate genes mediating fragmentation of the third suborbital bone (SO3) directly inferior to the orbit of the eye. We integrated positional genomic information using emerging Astyanax resources, and linked these intervals to homologous (syntenic) regions of the Danio rerio genome. We identified a discrete, approximately 6 Mb, conserved region wherein the gene causing SO3 fragmentation likely resides. We interrogated this interval for genes demonstrating significant differential expression using mRNA-seq analysis of cave and surface morphs across life history. We then assessed genes with known roles in craniofacial evolution and development based on GO term annotation. Finally, we screened coding sequence alterations in this region, identifying two key genes: transforming growth factor β3 (tgfb3) and bone morphogenetic protein 4 (bmp4). Of these candidates, tgfb3 is most promising as it demonstrates significant differential expression across multiple stages of development, maps close (<1 Mb) to the fragmentation critical locus, and is implicated in a variety of other animal systems (including humans) in non-syndromic clefting and malformations of the cranial sutures. Both abnormalities are analogous to the failure-to-fuse phenotype that we observe in SO3 fragmentation. This integrative approach will enable discovery of the causative genetic lesions leading to complex craniofacial features analogous to human craniofacial disorders. This work underscores the value of cave-dwelling fish as a powerful evolutionary model of craniofacial disease, and demonstrates the power of integrative system-level studies for informing the genetic basis of craniofacial aberrations in nature.
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Affiliation(s)
- Joshua B. Gross
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
| | - Bethany A. Stahl
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
| | - Amanda K. Powers
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
| | - Brian M. Carlson
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
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Amelanism in the corn snake is associated with the insertion of an LTR-retrotransposon in the OCA2 gene. Sci Rep 2015; 5:17118. [PMID: 26597053 PMCID: PMC4657000 DOI: 10.1038/srep17118] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/26/2015] [Indexed: 12/21/2022] Open
Abstract
The corn snake (Pantherophis guttatus) is a new model species particularly appropriate for investigating the processes generating colours in reptiles because numerous colour and pattern mutants have been isolated in the last five decades. Using our captive-bred colony of corn snakes, transcriptomic and genomic next-generation sequencing, exome assembly, and genotyping of SNPs in multiple families, we delimit the genomic interval bearing the causal mutation of amelanism, the oldest colour variant observed in that species. Proceeding with sequencing the candidate gene OCA2 in the uncovered genomic interval, we identify that the insertion of an LTR-retrotransposon in its 11th intron results in a considerable truncation of the p protein and likely constitutes the causal mutation of amelanism in corn snakes. As amelanistic snakes exhibit white, instead of black, borders around an otherwise normal pattern of dorsal orange saddles and lateral blotches, our results indicate that melanocytes lacking melanin are able to participate to the normal patterning of other colours in the skin. In combination with research in the zebrafish, this work opens the perspective of using corn snake colour and pattern variants to investigate the generative processes of skin colour patterning shared among major vertebrate lineages.
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Alterations in Mc1r gene expression are associated with regressive pigmentation in Astyanax cavefish. Dev Genes Evol 2015; 225:367-75. [PMID: 26462499 DOI: 10.1007/s00427-015-0517-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 09/08/2015] [Indexed: 12/16/2022]
Abstract
Diverse changes in coloration across distant taxa are mediated through alterations in certain highly conserved pigmentation genes. Among these genes, Mc1r is a frequent target for mutation, and many documented alterations involve coding sequence changes. We investigated whether regulatory mutations in Mc1r may also contribute to pigmentation loss in the blind Mexican cavefish, Astyanax mexicanus. This species comprises multiple independent cave populations that have evolved reduced (or absent) melanic pigmentation as a consequence of living in darkness for millions of generations. Among the most salient cave-associated traits, complete absence (albinism) or reduced levels of pigmentation (brown) have long been the focus of degenerative pigmentation research in Astyanax. These two Mendelian traits have been linked to specific coding mutations in Oca2 (albinism) and Mc1r (brown). However, four of the seven caves harboring the brown phenotype exhibit unaffected coding sequences compared to surface fish. Thus, diverse genetic changes involving the same genes likely impact reduced pigmentation among cavefish populations. Using both sequence and expression analyses, we show that certain cave-dwelling populations harboring the brown mutation have substantial alterations to the putative Mc1r cis-regulatory region. Several of these sequence mutations in the Mc1r 5' region were present across multiple, independent cave populations. This study suggests that pigmentation reduction in Astyanax cavefish evolves through a combination of both coding and cis-regulatory mutations. Moreover, this study represents one of the first attempts to identify regulatory alterations linked to regressive changes in cave-dwelling populations of A. mexicanus.
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Gross JB, Meyer B, Perkins M. The rise of Astyanax cavefish. Dev Dyn 2015; 244:1031-1038. [PMID: 25601346 PMCID: PMC4508244 DOI: 10.1002/dvdy.24253] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/08/2015] [Accepted: 01/10/2015] [Indexed: 01/01/2023] Open
Abstract
Numerous animals have invaded subterranean caverns and evolved remarkably similar features. These features include loss of vision and pigmentation, and gains in nonvisual sensation. This broad convergence echoes smaller-scale convergence, in which members of the same species repeatedly evolve the same cave-associated phenotypes. The blind Mexican tetra of the Sierra de El Abra region of northeastern Mexico has a complex origin, having recurrently colonized subterranean environments through numerous invasions of surface-dwelling fish. These colonizations likely occurred ∼1-5 MYa. Despite evidence of historical and contemporary gene flow between cave and surface forms, the cave-associated phenotype appears to remain quite stable in nature. This model system has provided insight to the mechanisms of phenotypic regression, the genetic basis for constructive trait evolution, and the origin of behavioral novelties. Here, we document the rise of this model system from its discovery by a Mexican surveyor in 1936, to a powerful system for cave biology and contemporary genetic research. The recently sequenced genome provides exciting opportunities for future research, and will help resolve several long-standing biological problems. Developmental Dynamics 244:1031-1038, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Joshua B Gross
- University of Cincinnati, Department of Biological Sciences, Cincinnati Ohio
| | - Bradley Meyer
- University of Cincinnati, Department of Biological Sciences, Cincinnati Ohio
| | - Molly Perkins
- University of Cincinnati, Department of Biological Sciences, Cincinnati Ohio
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McGaugh SE, Gross JB, Aken B, Blin M, Borowsky R, Chalopin D, Hinaux H, Jeffery WR, Keene A, Ma L, Minx P, Murphy D, O’Quin KE, Rétaux S, Rohner N, Searle SMJ, Stahl BA, Tabin C, Volff JN, Yoshizawa M, Warren WC. The cavefish genome reveals candidate genes for eye loss. Nat Commun 2014; 5:5307. [PMID: 25329095 PMCID: PMC4218959 DOI: 10.1038/ncomms6307] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
Natural populations subjected to strong environmental selection pressures offer a window into the genetic underpinnings of evolutionary change. Cavefish populations, Astyanax mexicanus (Teleostei: Characiphysi), exhibit repeated, independent evolution for a variety of traits including eye degeneration, pigment loss, increased size and number of taste buds and mechanosensory organs, and shifts in many behavioural traits. Surface and cave forms are interfertile making this system amenable to genetic interrogation; however, lack of a reference genome has hampered efforts to identify genes responsible for changes in cave forms of A. mexicanus. Here we present the first de novo genome assembly for Astyanax mexicanus cavefish, contrast repeat elements to other teleost genomes, identify candidate genes underlying quantitative trait loci (QTL), and assay these candidate genes for potential functional and expression differences. We expect the cavefish genome to advance understanding of the evolutionary process, as well as, analogous human disease including retinal dysfunction.
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Affiliation(s)
- Suzanne E. McGaugh
- The Genome Institute, Washington University, Campus Box 8501, St Louis, Missouri 63108, USA
| | - Joshua B. Gross
- Department of Biological Sciences, University of Cincinnati, 711B Rieveschl Hall, 312 College Drive, Cincinnati, Ohio 45221, USA
| | - Bronwen Aken
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Maryline Blin
- DECA group, Neurobiology and Development Laboratory, CNRS-Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - Richard Borowsky
- Department of Biology, New York University, New York, New York 10003-6688, USA
| | - Domitille Chalopin
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR 5242, UCBL, 46 allée d’Italie, Lyon F-69364, France
| | - Hélène Hinaux
- DECA group, Neurobiology and Development Laboratory, CNRS-Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - William R. Jeffery
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
| | - Alex Keene
- Department of Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Li Ma
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
| | - Patrick Minx
- The Genome Institute, Washington University, Campus Box 8501, St Louis, Missouri 63108, USA
| | - Daniel Murphy
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Kelly E. O’Quin
- Department of Biology, Centre College, 600 West Walnut St, Danville, Kentucky 40422, USA
| | - Sylvie Rétaux
- DECA group, Neurobiology and Development Laboratory, CNRS-Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - Nicolas Rohner
- Harvard Medical School Department of Genetics, 77 Avenue Louis Pasteur; NRB 360, Boston, Massachusetts 02115, USA
| | - Steve M. J. Searle
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Bethany A. Stahl
- Department of Biological Sciences, University of Cincinnati, 711B Rieveschl Hall, 312 College Drive, Cincinnati, Ohio 45221, USA
| | - Cliff Tabin
- Harvard Medical School Department of Genetics, 77 Avenue Louis Pasteur; NRB 360, Boston, Massachusetts 02115, USA
| | - Jean-Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR 5242, UCBL, 46 allée d’Italie, Lyon F-69364, France
| | - Masato Yoshizawa
- Department of Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Wesley C. Warren
- The Genome Institute, Washington University, Campus Box 8501, St Louis, Missouri 63108, USA
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Next generation phylogeography of cave and surface Astyanax mexicanus. Mol Phylogenet Evol 2014; 79:368-74. [PMID: 25014568 DOI: 10.1016/j.ympev.2014.06.029] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/25/2014] [Accepted: 06/30/2014] [Indexed: 01/08/2023]
Abstract
The loss of traits is a commonly observed evolutionary pattern in cave organisms, but due to extensive morphological convergence, inferring relationships between cave and surface populations can be difficult. For instance, Astyanax mexicanus (the blind Mexican cavefish) is thought to have repeatedly lost its eyes following colonization of cave environments, but the number of evolutionarily independent invasions of this species into caves remains unclear. Because of these repeated losses, it has become a model organism for studying the genetic basis of phenotypic trait loss. Here we reconstruct a high-resolution phylogeography for A. mexicanus inferred from both mitochondrial DNA and several thousand single nucleotide polymorphisms. We provide novel insight into the origin of cave populations from the Sabinos and Río Subterráneo caves and present evidence that the Sabinos cave population is part of a unique cave lineage unrelated to other A. mexicanus cave populations. Our results indicate A. mexicanus cave populations have at least four independent origins.
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Katz PS, Lillvis JL. Reconciling the deep homology of neuromodulation with the evolution of behavior. Curr Opin Neurobiol 2014; 29:39-47. [PMID: 24878891 DOI: 10.1016/j.conb.2014.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/02/2014] [Accepted: 05/05/2014] [Indexed: 01/05/2023]
Abstract
The evolution of behavior seems inconsistent with the deep homology of neuromodulatory signaling. G protein coupled receptors (GPCRs) evolved slowly from a common ancestor through a process involving gene duplication, neofunctionalization, and loss. Neuropeptides co-evolved with their receptors and exhibit many conserved functions. Furthermore, brain areas are highly conserved with suggestions of deep anatomical homology between arthropods and vertebrates. Yet, behavior evolved more rapidly; even members of the same genus or species can differ in heritable behavior. The solution to the paradox involves changes in the compartmentalization, or subfunctionalization, of neuromodulation; neurons shift their expression of GPCRs and the content of monoamines and neuropeptides. Furthermore, parallel evolution of neuromodulatory signaling systems suggests a route for repeated evolution of similar behaviors.
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Affiliation(s)
- Paul S Katz
- Neuroscience Institute, Georgia State University, PO Box 5030, Atlanta, GA 30302, United States.
| | - Joshua L Lillvis
- Janelia Farm Research Campus, Howard Hughes Medical Institute, United States
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Roesti M, Gavrilets S, Hendry AP, Salzburger W, Berner D. The genomic signature of parallel adaptation from shared genetic variation. Mol Ecol 2014; 23:3944-56. [PMID: 24635356 DOI: 10.1111/mec.12720] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/12/2014] [Accepted: 03/12/2014] [Indexed: 12/19/2022]
Abstract
Parallel adaptation is common and may often occur from shared genetic variation, but the genomic consequences of this process remain poorly understood. We first use individual-based simulations to demonstrate that comparisons between populations adapted in parallel to similar environments from shared variation reveal a characteristic genomic signature around a selected locus: a low-divergence valley centred at the locus and flanked by twin peaks of high divergence. This signature is initiated by the hitchhiking of haplotype tracts differing between derived populations in the broader neighbourhood of the selected locus (driving the high-divergence twin peaks) and shared haplotype tracts in the tight neighbourhood of the locus (driving the low-divergence valley). This initial hitchhiking signature is reinforced over time because the selected locus acts as a barrier to gene flow from the source to the derived populations, thus promoting divergence by drift in its close neighbourhood. We next empirically confirm the peak-valley-peak signature by combining targeted and RAD sequence data at three candidate adaptation genes in multiple marine (source) and freshwater (derived) populations of threespine stickleback. Finally, we use a genome-wide screen for the peak-valley-peak signature to discover additional genome regions involved in parallel marine-freshwater divergence. Our findings offer a new explanation for heterogeneous genomic divergence and thus challenge the standard view that peaks in population divergence harbour divergently selected loci and that low-divergence regions result from balancing selection or localized introgression. We anticipate that genome scans for peak-valley-peak divergence signatures will promote the discovery of adaptation genes in other organisms.
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Affiliation(s)
- Marius Roesti
- Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
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36
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Complex craniofacial changes in blind cave-dwelling fish are mediated by genetically symmetric and asymmetric loci. Genetics 2014; 196:1303-19. [PMID: 24496009 DOI: 10.1534/genetics.114.161661] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The genetic regulators of regressive craniofacial morphologies are poorly understood. To shed light on this problem, we examined the freshwater fish Astyanax mexicanus, a species with surface-dwelling and multiple independent eyeless cave-dwelling forms. Changes affecting the skull in cavefish include morphological alterations to the intramembranous circumorbital bones encircling the eye. Many of these modifications, however, have evolved separately from eye loss, such as fragmentation of the third suborbital bone. To understand the genetic architecture of these eye-independent craniofacial alterations, we developed and scored 33 phenotypes in the context of an F2 hybrid mapping pedigree bred from Pachón cavefish and surface fish. We discovered several individuals exhibiting dramatic left-right differences in bone formation, such as extensive fragmentation on the right side only. This observation, along with well-known eye size asymmetry in natural cave-dwelling animals, led us to further evaluate left-right genetic differences for the craniofacial complex. We discovered three phenotypes, inclusive of bone fragmentation and fusion, which demonstrated a directional heritable basis only on one side. Interestingly, the overall areas of affected bones were genetically symmetric. Phenotypic effect plots of these novel craniofacial QTL revealed that cave alleles are associated with abnormal conditions such as bony fusion and fragmentation. Moreover, many linked loci overlapped with other cave-associated traits, suggesting regressive craniofacial changes may evolve through linkage or as antagonistic pleiotropic consequences of cave-associated adaptations. These novel findings illuminate significant craniofacial changes accompanying evolution in complete darkness and reveal complex changes to the skull differentially influenced by genetic changes affecting the left and right sides.
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Bilandžija H, Ma L, Parkhurst A, Jeffery WR. A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis. PLoS One 2013; 8:e80823. [PMID: 24282555 PMCID: PMC3840000 DOI: 10.1371/journal.pone.0080823] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/14/2013] [Indexed: 12/15/2022] Open
Abstract
Albinism, the loss of melanin pigmentation, has evolved in a diverse variety of cave animals but the responsible evolutionary mechanisms are unknown. In Astyanax mexicanus, which has a pigmented surface dwelling form (surface fish) and several albino cave-dwelling forms (cavefish), albinism is caused by loss of function mutations in the oca2 gene, which operates during the first step of the melanin synthesis pathway. In addition to albinism, cavefish have evolved differences in behavior, including feeding and sleep, which are under the control of the catecholamine system. The catecholamine and melanin synthesis pathways diverge after beginning with the same substrate, L-tyrosine. Here we describe a novel relationship between the catecholamine and melanin synthesis pathways in Astyanax. Our results show significant increases in L-tyrosine, dopamine, and norepinephrine in pre-feeding larvae and adult brains of Pachón cavefish relative to surface fish. In addition, norepinephrine is elevated in cavefish adult kidneys, which contain the teleost homologs of catecholamine synthesizing adrenal cells. We further show that the oca2 gene is expressed during surface fish development but is downregulated in cavefish embryos. A key finding is that knockdown of oca2 expression in surface fish embryos delays the development of pigmented melanophores and simultaneously increases L-tyrosine and dopamine. We conclude that a potential evolutionary benefit of albinism in Astyanax cavefish may be to provide surplus L-tyrosine as a precursor for the elevated catecholamine synthesis pathway, which could be important for adaptation to the challenging cave environment.
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Affiliation(s)
- Helena Bilandžija
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
- Department of Biology, University of Maryland, Maryland, United States of America
| | - Li Ma
- Department of Biology, University of Maryland, Maryland, United States of America
| | - Amy Parkhurst
- Department of Biology, University of Maryland, Maryland, United States of America
| | - William R. Jeffery
- Department of Biology, University of Maryland, Maryland, United States of America
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