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Kavalco KF, Pasa R. Chromosomal Radiation: A model to explain karyotypic diversity in cryptic species. Genet Mol Biol 2023; 46:e20230116. [PMID: 37815421 PMCID: PMC10563172 DOI: 10.1590/1678-4685-gmb-2023-0116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/22/2023] [Indexed: 10/11/2023] Open
Abstract
We present a concept that explains the pattern of occurrence of widely distributed organisms with large chromosomal diversity, large or small molecular divergence, and the insufficiency or absence of morphological identity. Our model is based on cytogenetic studies associated with molecular and biological data and can be applied to any lineage of sister species, chronospecies, or cryptic species. Through the evaluation of the karyotypic macrostructure, as the physical location of genes e satellites DNAs, in addition to phylogenetic reconstructions from mitochondrial and nuclear genes, per example, we have observed morphologically indistinguishable individuals presenting different locally fixed karyomorphs with phylogeographic discontinuity. The biological process behind this pattern is seen in many groups of cryptic species, in which variation lies mainly in the organization of their genomes but not necessarily in the ecosystems they inhabit or in their external morphology. It's similar to the processes behind other events observed in the distribution of lineages. In this work, we explore the hypothesis of a process analogous to ecological-evolutionary radiation, which we called Chromosomal Radiation. Chromosomal Radiation can be adaptive or non-adaptive and applied to different groups of organisms.
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Affiliation(s)
- Karine Frehner Kavalco
- Universidade Federal de Viçosa, Instituto de Ciências Biológicas e da Saúde, Laboratório de Genética Ecológica e Evolutiva (LaGEEvo), Campus Rio Paranaíba, Rio Paranaíba, MG, Brazil
- Universidade Federal de Viçosa, Instituto de Ciências Biológicas e da Saúde, Laboratório de Bioinformática e Genômica, Campus Rio Paranaíba, Rio Paranaíba, MG, Brazil
| | - Rubens Pasa
- Universidade Federal de Viçosa, Instituto de Ciências Biológicas e da Saúde, Laboratório de Genética Ecológica e Evolutiva (LaGEEvo), Campus Rio Paranaíba, Rio Paranaíba, MG, Brazil
- Universidade Federal de Viçosa, Instituto de Ciências Biológicas e da Saúde, Laboratório de Bioinformática e Genômica, Campus Rio Paranaíba, Rio Paranaíba, MG, Brazil
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Srikulnath K, Ahmad SF, Singchat W, Panthum T. Why Do Some Vertebrates Have Microchromosomes? Cells 2021; 10:2182. [PMID: 34571831 PMCID: PMC8466491 DOI: 10.3390/cells10092182] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 12/27/2022] Open
Abstract
With more than 70,000 living species, vertebrates have a huge impact on the field of biology and research, including karyotype evolution. One prominent aspect of many vertebrate karyotypes is the enigmatic occurrence of tiny and often cytogenetically indistinguishable microchromosomes, which possess distinctive features compared to macrochromosomes. Why certain vertebrate species carry these microchromosomes in some lineages while others do not, and how they evolve remain open questions. New studies have shown that microchromosomes exhibit certain unique characteristics of genome structure and organization, such as high gene densities, low heterochromatin levels, and high rates of recombination. Our review focuses on recent concepts to expand current knowledge on the dynamic nature of karyotype evolution in vertebrates, raising important questions regarding the evolutionary origins and ramifications of microchromosomes. We introduce the basic karyotypic features to clarify the size, shape, and morphology of macro- and microchromosomes and report their distribution across different lineages. Finally, we characterize the mechanisms of different evolutionary forces underlying the origin and evolution of microchromosomes.
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Affiliation(s)
- Kornsorn Srikulnath
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- The International Undergraduate Program in Bioscience and Technology, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Amphibian Research Center, Hiroshima University, 1-3-1, Kagamiyama, Higashihiroshima 739-8526, Japan
| | - Syed Farhan Ahmad
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- The International Undergraduate Program in Bioscience and Technology, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Worapong Singchat
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Thitipong Panthum
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
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Lunghi E, Manenti R, Canciani G, Scarì G, Pennati R, Ficetola GF. Thermal equilibrium and temperature differences among body regions in European plethodontid salamanders. J Therm Biol 2016; 60:79-85. [PMID: 27503719 DOI: 10.1016/j.jtherbio.2016.06.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 06/13/2016] [Indexed: 12/23/2022]
Abstract
Information on species thermal physiology is extremely important to understand species responses to environmental heterogeneity and changes. Thermography is an emerging technology that allows high resolution and accurate measurement of body temperature, but until now it has not been used to study thermal physiology of amphibians in the wild. Hydromantes terrestrial salamanders are strongly depending on ambient temperature for their activity and gas exchanges, but information on their body temperature is extremely limited. In this study we tested if Hydromantes salamanders are thermoconform, we assessed whether there are temperature differences among body regions, and evaluated the time required to reach the thermal equilibrium. During summers of 2014 and 2015 we analysed 56 salamanders (Hydromantes ambrosii and Hydromantes italicus) using infrared thermocamera. We photographed salamanders at the moment in which we found them and 1, 2, 3, 4, 5 and 15min after having kept them in the hands. Body temperature was equal to air temperature; salamanders attained the equilibrium with air temperature in about 8min, the time required to reach equilibrium was longer in individuals with large body size. We detected small temperature differences between body parts, the head being slightly warmer than the body and the tail (mean difference: 0.05°C). These salamanders quickly reach the equilibrium with the environment, thus microhabitat measurement allows obtaining accurate information on their tolerance limits.
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Affiliation(s)
- Enrico Lunghi
- Universität Trier Fachbereich VI Raum-und Umweltwissenschaften Biogeographie, Campus I, Gebäude N Universitätsring 15, 54286 Trier, Germany; Natural Oasis, Via di Galceti 141, 59100 Prato, Italy; Museo di Storia Naturale dell'Università di Firenze, Sezione di Zoologia "La Specola", Via Romana 17, 50125 Firenze, Italy.
| | - Raoul Manenti
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | | | - Giorgio Scarì
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Roberta Pennati
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Gentile Francesco Ficetola
- Laboratoire d'Ecologie Alpine (LECA), Université Grenoble-Alpes, F-38000 Grenoble, France; Centre National de la Recherche Scientifique (CNRS), LECA, F-38000 Grenoble, France
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Kawakami T, Butlin RK, Cooper SJB. Chromosomal Speciation Revisited: Modes of Diversification in Australian Morabine Grasshoppers (Vandiemenella, viatica Species Group). INSECTS 2011; 2:49-61. [PMID: 26467499 PMCID: PMC4553423 DOI: 10.3390/insects2010049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 03/10/2011] [Accepted: 03/15/2011] [Indexed: 11/30/2022]
Abstract
Chromosomal rearrangements can alter the rate and patterns of gene flow within or between species through a reduction in the fitness of chromosomal hybrids or by reducing recombination rates in rearranged areas of the genome. This concept, together with the observation that many species have structural variation in chromosomes, has led to the theory that the rearrangements may play a direct role in promoting speciation. Australian morabine grasshoppers (genus Vandiemenella, viatica species group) are an excellent model for studying the role of chromosomal rearrangement in speciation because they show extensive chromosomal variation, parapatric distribution patterns, and narrow hybrid zones at their boundaries. This species group stimulated development of one of the classic chromosomal speciation models, the stasipatric speciation model proposed by White in 1968. Our population genetic and phylogeographic analyses revealed extensive non-monophyly of chromosomal races along with historical and on-going gene introgression between them. These findings suggest that geographical isolation leading to the fixation of chromosomal variants in different geographic regions, followed by secondary contact, resulted in the present day parapatric distributions of chromosomal races. The significance of chromosomal rearrangements in the diversification of the viatica species group can be explored by comparing patterns of genetic differentiation between rearranged and co-linear parts of the genome.
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Affiliation(s)
- Takeshi Kawakami
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA.
| | - Roger K Butlin
- Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
| | - Steven J B Cooper
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA 5000, Australia.
- Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, SA 5005, Australia.
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