https://orcid.org/0009-0007-4019-5489
Figures
Abstract
The Labeoninae subfamily is a highly diversified but demonstrably monophyletic lineage of cyprinid fishes comprising five tribes and six incertae sedis genera. This widely distributed assemblage contains some 48 genera and around 480 recognized species distributed in freshwaters of Africa and Asia. In this study, the karyotypes and other chromosomal properties of five Labeoninae species found in Thailand Labeo chrysophekadion (Labeonini) and Epalzeorhynchos bicolor, Epalzeorhynchos munense, Henicorhynchus siamensis, Thynnichthys thynnoides (´Osteochilini´) were examined using conventional and molecular cytogenetic protocols. Our results confirmed a diploid chromosome number (2n) invariably 2n = 50, but the ratio of uni- and bi-armed chromosomes was highly variable among their karyotypes, indicating extensive structural chromosomal rearrangements. Karyotype of L. chrysophekadion contained 10m+6sm+20st+14a, 32m+10sm+8st for H. siamensis, 20m+12sm+10st+8a in E. bicolor, 20m+8sm+8st+14a in E. munense, and 18m+24sm+8st in T. thynnoides. Except for H. siamensis, which had four sites of 5S rDNA sites, other species under study had only one chromosome pair with those sites. In contrast, only one pair containing 18S rDNA sites were found in the karyotypes of three species, whereas two sites were found in that of E. bicolor. These cytogenetic patterns indicated that the cytogenomic divergence patterns of these labeonine species largely corresponded to the inferred phylogenetic tree. In spite of the 2n stability, diverse patterns of rDNA and microsatellite distribution as well as their various karyotype structures demonstrated significant evolutionary differentiation of Labeoninae genomes as exemplified in examined species. Labeoninae offers a traditional point of view on the evolutionary forces fostering biological diversity, and the recent findings add new pieces to comprehend the function of structural chromosomal rearrangements in adaption and speciation.
Citation: Khensuwan S, de Menezes Cavalcante Sassi F, Rosa de Moraes RL, Rab P, Liehr T, Supiwong W, et al. (2024) Chromosomes of Asian cyprinid fishes: Novel insight into the chromosomal evolution of Labeoninae (Teleostei, Cyprinidae). PLoS ONE 19(2): e0292689. https://doi.org/10.1371/journal.pone.0292689
Editor: Ishtiyaq Ahmad, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, INDIA
Received: May 12, 2023; Accepted: September 26, 2023; Published: February 7, 2024
Copyright: © 2024 Khensuwan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper.
Funding: This research was supported by the National Research Council of Thailand (NCRT) in the form of a grant to SK [NRCT-RGJ63003-068] and by the Thailand science research and innovation fund and the University of Phayao in the form of a grant to KS [FF66-UoE013]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."
Competing interests: The authors have declared that no competing interests exist.
Introduction
Around 48 genera and more than 480 species compose the demonstrably monophyletic Labeoninae (Cyprinidae, Cypriniformes) [1], which inhabits the fast-flowing rivers and streams of Africa and Asia [2]. Because of their beautiful body patterns and large size of some species, these fishes are frequently targets of the aquarium trade as well as artisanal fisheries, accounting for 18% of total aquatic animal production in 2020 [3]. However, most cytogenetic research in this group is limited to the report of the diploid chromosome number (2n) and the karyotype composition [4, 5], which does not preclude recognition of a wide range of chromosomal diversity.
All Labeoninae species are evolutionary diploid, with 2n ranging from 48 to 50, in contrast to the tetra- and hexaploid lineages of other Cyprinidae subfamilies, namely Barbinae, Cyprininae, Probarbinae, Schizopygopsinae, Schizothoracinae, Smiliogastrinae, Spinibarbinae, and Torinae [1, 4, 6, 7]. Phylogenetic reconstructions suggest that the divergence of cyprinid lineages began with diploid species about 70 million years ago (Mya), progressed through a tetraploidization stage between 45 and 20 Mya, and then experienced a more recent hexaploidization event in the last 20 Mya. However, the exact timing of this divergence is still debated [7]. According to Yang et al. [7], the Labeoninae family underwent diversification around 43.6 Mya and was found to be the sister basal branch of all other cyprinids [6–9].
The species of the evolutionary diploid subfamilies Acrossocheilinae and ’Poropuntiinae’ both have a conserved 2n of 50, however those of Labeoninae and Smiliogastrinae vary between values of 48 and 50 chromosomes (Table 1). This reduction in 2n was most likely caused by chromosomal fusions, which, in certain rare cases, are associated with the origin of the sex chromosomes [10]. Despite the widespread conservation of their 2n, Labeoninae species have differences in the macro- and microstructure of the karyotypes as evidenced by the different fundamental numbers (NF) and 18S rDNA sites distribution (Table 1). This suggests that pericentric inversions played a significant role in their karyotype evolution. In this context, molecular cytogenetics emerges as a crucial tool to identify the karyotype dynamics in fishes, as has already been demonstrated for several Cyprinidae species [11–18]. Indeed, the mapping of repetitive sequences, which make up the majority of the eukaryotic genome, is widely utilized in fish cytogenetics and has a significant potential to further understand the origin process of sex and B chromosomes, as well as karyotype differentiation [19].
The species analyzed in this study are highlighted in red.
In general, available data demonstrate that although almost all cyprinoid species share the same macrostructure of their karyotypes (i.e.: 2n = 50 and karyotypes dominated by bi-armed chromosomes), they diverge in patterns of C-positive heterochromatin, and rDNA distribution [18, 20–26]. Considering this scenario, our study provides novel cytogenetic data for five Labeoninae species, namely Epalzeorhynchos bicolor Smith (1931), E. munense Smith (1934), Henicorhynchus siamensis Sauvage (1881), Thynnichthys thynnoides Bleeker (1852) and Labeo chrysophekadion Bleeker (1849) from two tribes (Osteochilini and Labeonini sensu Tan & Armbruster, 2018). These results add to our understanding of the ways in which structural chromosomal rearrangements play a role in speciation and adaptation.
Material and methods
Sampling
Samples have been collected at five distinct sites that belong to Thailand’s Mae Klong, Songkhram, and Chao Phraya drainage systems, as indicated in Fig 1 and Table 2. We included two species that were collected in the same basins, but were very low abundance in wild habitats [73, 74]. Considering that bloodstock wilds have been successfully produced by artificial insemination in aquaculture farms in Thailand, fish samples were also purchased directly from the Ban Pong Fish Market in Ratchaburi province. The analyzed individuals have been deposited in the fish collections at KhonKaen University’s Cytogenetic Laboratory, Department of Biology, and Faculty of Science. All the species examined here were correctly identified using the morphological criteria [75, 76]. Mitotic chromosomes were obtained from the anterior kidney according to Bertollo et al. [77]. We used silver nitrate (AgNO3) to visualize the nucleolar organizer regions (Ag-NOR) [78]. We used clove oil (Eugenol 3%) for anesthesia following the sacrifice of the individuals, as approved by the Animal Ethics Committee of KhonKaen University based on the Ethics of Animal Experimentation of the National Research Council of Thailand (Record No. IACUC-KKU-105/63). This research also received authorization to the animal care and use license for scientific research U1-07864-2561 (COA.No.MU-IACUC 2019/007). For the fishes of the Mae Klong Basin, study was approved in Mahidol University and fish collection authorized by Department of fisheries in Thailand, license number was 49/2564.
Thailand map showing the collection sites of the five species studied including 1. Labeo chrysophekadion (green circles); 2. Henicorhynchus siamensis (orange circles); 3. Epalzeorhynchos bicolor (pink circles); 4. Epalzeorhynchos munense (yellow circles); 5. Thynnichthys thynnoides (red circles). Scale bar = 1 cm.
Individuals of E. bicolor and E. munense were gathered from Ban Pong Fish Market, Ratchaburi province (13°51’42.6"N 99°52’48.8"E).
Fluorescence in situ hybridization (FISH)
Fluorescence in situ hybridization experiments were conducted under high stringency conditions [79] to identify both 5S and 18S ribosomal DNA classes and the microsatellites (CA)15, (GC)15, (TA)15, (CAA)10 (GAA)10 (CAG)10 (CAT)10 and (CGG)10 The 5S ribosomal probe had 200 bp of the non-transcribed spacer (NTS) and 120 base pairs (bp) of the 5S rRNA transcribing gene [80]. The 18S rDNA was derived from the nuclear DNA of the wolf fish Hoplias malabaricus using PCR, and it corresponded to the 1400 bp segment of the 18S rRNA gene [81]. Both rDNA probes were directly labelled with the Nick-Translation mix kit (Jena Bioscience, Jena, Germany), where 5S rDNA was labeled in red with Atto550-dUTP and the 18S rDNA was labelled in green with Atto448-dUTP, according to the manufacturer’s instructions. The microsatellite sequences were directly labelled with Cy-3 during the synthesis, described by Kubat et al. [82].
Image processing
To confirm the results, we used at least 20 metaphase spreads per individual. Images were captured with an Axioplan II microscope (Carl Zeiss Jena GmbH, Germany) with CoolSNAP, and processed using ISIS (MetaSystems Hard & Software GmbH). Chromosomes were classified as metacentric (m), submetacentric (sm), subtelocentric (st), and acrocentric (a) according to their short/long arms ratio [83].
Results
All five examined species, for both females and males, possessed invariably, 2n = 50, but with distinct karyotype compositions: 10m+6sm+20st+14a in Labeo chrysophekadion, 32m+10sm+8st in Henicorhynchos siamensis (Fig 2A and 2B), 20m+12sm+10st+8a in Epalzeorhynchos bicolor, 20m+8sm+8st+14a in E. munense, and 18m+24sm+8st in Thynnichthys thynnoides (Fig 3A, 3B and 3G). Single Ag-NOR sites were detected in all species at the telomeric region of p arms. In the genome of E. bicolor and E. munense, the 5S rDNA was distributed in the centromeric region of st pairs 20 and 15. On the other hand, H. siamensis had these sites located in four chromosomal pairs at the centromeric region (pairs 3, 6, 17, 19). For L. chrysophekadion (pair 7, Fig 2E) and T. thynnoides (pairs 17, 22, Fig 3I), the 5S rDNA was found in the telomeric region of the p arms. The 18S rDNA distribution corresponded to the Ag-NOR signals: pair 9 in L. chrysophekadion, pair 18 in H. siamensis pairs 19 and 21 in E. bicolor, pair 11 in E. munense, and pair 10 in T. thynnoides.
Karyotypes of L. chrysophekadion (A,C,E) and Henicorhyncus siamensis (B,D,F) organized from chromosomes after Giemsa-staining, Ag-NOR impregnation and FISH with 5S and 18S probes. Chromosomes were counterstained with DAPI (blue). Arrows indicate the positive FISH results. Bar = 5 μm.
Karyotypes of E. bicolor (A,C,E), E. munense (B,D,F), and T. thynnoides (G,H,I) arranged from Giemsa- and Ag-NOR-stained chromosomes and chromosomes after FISH with 5S (red) and 18S (green) rDNA probes. Chromosomes were counterstained with DAPI (blue). The positive FISH signals are indicated by arrows. Scale bar = 5 μm.
Microsatellite mapping showed species-specific patterns and mostly telomeric signals for all species (Figs 4–8). For the (CA)15, dispersed signals were seen in the chromosomes of L. chrysophekadion, whereas T. thynnoides and H. siamensis only displayed telomeric signals, in contrast to E. bicolor and E. munense, which additionally display one set of signals marked in the pericentromeric region. The (GC)15 was found in the telomeres of T. thynnoides and E. munense; however, in E. bicolor and H. siamensis, only one chromosome pair was marked, and this motif was dispersed in L. chrysophekadion. The (GAA)10 accumulates in the telomeres of other species but was distributed in the chromosomes of T. thynnoides and E. munense. On the other hand, (CAT)10 was only accumulated in telomeres of E. bicolor, in contrast to dispersed in other species. All species, except E. munense with a single chromosome pair marked, had telomeric signals for the (CAA)10 probe. The (TA)15 was dispersed in L. chrysophekadion and H. siamensis chromosomes, but accumulated in telomeres of all other species. The (CAG)10 was found dispersed in L. chrysophekadion and T. thynnoides, in the telomeres of all chromosomes of E. munense, restricted to the telomeric region of a single chromosome pair in E. bicolor, and bitelomeric in a single pair of H. siamensis in addition to a telomeric mark on short arm of a metacentric pair. Finally, in H. siamensis and T. thynnoides, the (CGG)10 probe was found in the telomeres of all chromosomes, but in E. munense, it was only identified as a strong signal on one pair in the centromeric region, in contrast to a scattered pattern in E. bicolor and T. thynnoides chromosomes.
Distribution of microsatellite sequences (CA)15, (GC)15, (TA)15, (CAA)10 (GAA)10 (CAG)10 (CAT)10, and (CGG)10 onto L. chrysophekadion metaphase chromosomes.
Distribution of microsatellite sequences (CA)15, (GC)15, (TA)15, (CAA)10 (GAA)10 (CAG)10 (CAT)10 and (CGG)10 onto H. siamensis metaphase chromosomes.
Distribution of microsatellite sequences (CA)15, (GC)15, (TA)15, (CAA)10 (GAA)10 (CAG)10 (CAT)10 and (CGG)10 onto E. bicolor metaphase chromosomes.
Distribution of microsatellite sequences (CA)15, (GC)15, (TA)15, (CAA)10 (GAA)10 (CAG)10 (CAT)10 and (CGG)10 onto E. munense metaphase chromosomes.
Distribution of microsatellite sequences (CA)15, (GC)15, (TA)15, (CAA)10 (GAA)10 (CAG)10 (CAT)10 and (CGG)10 onto T. thynnoides metaphase chromosomes.
Discussion
For the great majority of species reviewed in Table 1, including those in this study, Labeoninae has 2n = 50, a diploid number which is also hypothesized as a basal for cypriniform fishes [11, 18, 84]. Despite their conservative 2n, significant variations in karyotype structures were observed in both Epalzeorhynchos species as well as other ones investigated herein. The different proportions of bi-armed chromosomes (metacentric and submetacentric) in the karyotypes imply that rearrangements like pericentric inversions may have acted during their karyotypic differentiation. It is also remarkable that a variety of karyotype re-organization events occured among the diversification of populations, as observed in the distribution of Ag-NOR/18S rDNA. Even though rDNAs are conservative elements of the eukaryotic genomes [85], the 18S rDNA typically occupies a terminal position in chromosomes, suggesting that these regions could represent recombination hotspots [86], feature also observed in Labeoninae karyotypes here investigated. In comparison, the 5S rDNA was found in both telomeric and centromeric regions, as also observed in the sister family ´Poropuntiinae´ (Cyprinidae). There, the 5S rDNA shows mostly a centromeric distribution, as observed in Hypsibarbus spp. and Mystacoleucus spp. [87]. Indeed, rDNA elements showed strikingly different patterns among cyprinid species, particularly in terms of variability in the number and position of 5S rDNA sites versus the more stable pattern of 18S rDNA sites. Such differences were especially notable in the sister clades Epalzeorhynchos and Henichorhynchus, where the former has a single chromosome pair carrying the 5S rDNA, while the last, four pairs. The mapping of repetitive sequences, especially ribosomal genes, has proven useful for estimating evolutionary karyotype changes in related species [86].
We demonstrated that the karyotype of E. bicolor is notably distinct from other populations described by Donsakul and Magtoon [44] (treated as Labeo bicolor). In their report, the karyotype contains a higher number of “a” chromosomes (12 pairs) than in our study (4 pairs). Such an enormous difference does not occur in the description of the karyotype of E. munense, where the acrocentrics vary from 6 to 8 pairs among populations. The extensive numerical variation of acrocentric chromosomes indicates that pericentric inversions might have occurred during the differentiation of their karyotypes. These rearrangements have been hypothesized to be crucial for local speciation and adaptation as well as for recombination suppression, especially in sex chromosomes [88–93]. This anticipated mechanism is widespread in cyprinoids chromosome evolution since most maintain the common 2n = 50, but are variable in the karyotype composition. Both Epalzeorhynchos species also greatly differ in the distribution of microsatellite sequences, as for the (GC)15, (CAA)10, and (CAG)10 microsatellites. Although mostly restricted to telomeric regions, where a significant fraction of repetitive DNA is localized [19], the number of chromosomes carrying these abovementioned motifs suggests that the dynamics of repetitive DNAs can be related to species divergences of this genus. In the genome evolution of various fish groups, the role of repetitive DNAs has been demonstrated [17–20, 94–98].
The proportion of biarmed chromosomes in Cyprinidae karyotypes is typically significantly greater than that of uniarmed ones [11]. The Epalzeorhynchos + Henicorhynchus + Thynnichthys clade (Osteochilinae) has a significantly higher number of (20) metacentric chromosomes than its sister clade Labeoninae, which possessed approximately 10 metacentric chromosomes making up their karyotypes as exemplified here in L. chrysophekadion (Fig 9). However, Labeo bata and L. dero have a more similar pattern to Osteochilini, with 18 and 26 metacentrics in karyotypes, respectively. The same higher proportion of metacentrics also occurs in Garrinae [4] and a high number of “m” chromosomes might be a plesiomorphic feature of the Osteochilinae and Garrinae, while the lower metacentric number in Labeoninae could represent a apomorphic feature of this tribe.
The common names of the species are indicated under the scientific name. The position of Epalzeorhynchos munense was manually added to our figure, since it is not included in the [2] phylogeny, thus requiring confirmation.
There are several fish species were 2n conservatism is found. Karyotype stasis/conservatism is primarily observed in marine fishes and is associated with a high degree of synteny between various DNA classes (e.g. Ellegren [99], Zhang et al. [100]). However, the conservation of 2n frequently follows the substantial changes in the karyotype structures and the distribution of repetitive DNAs in some families of Cyprinoidea. For example, the great 2n variation spanning from 42 in Acheilognathus gracilis (Acheilognathidae) [101] to 446 in Ptychobarbus dipogon (Cyprinidae) [102] has been recorded by families that experienced polyploidy throughout their chromosome evolution processes. In this context, the maintenance of 2n = 50 could represent the conservation of an ancestral trait in cyprinids [11, 84].
Our findings contributed to the knowledge of karyotypes and chromosome characteristics in the Labeoninae. Overall, these characteristics show that structural chromosome rearrangements, such as pericentric inversions, were mainly in charge of the wide numerical diversity of acrocentric chromosomes and had a major impact on the evolution of this cyprinid group. According to the detailed cytogenetic survey, trends of cytogenomic divergences can be identified in these Labeoninae species, which largely correspond to the inferred phylogenetic tree. Repetitive DNAs that demonstrated specificity in their distribution among species, such as ribosomal and microsatellite DNAs, were also effective indicators and drivers of particular genomic differentiation within Labeoninae.
References
- 1. Tan M, Armbruster JW. Phylogenetic classification of extant genera of fishes of the order Cypriniformes (Teleostei: Ostariophysi). Zootaxa 2018;4476(1): 6–39. pmid:30313339
- 2. Yang L, Arunachalam M, Sado T, Levin BA, Golubtsov AS, Freyhof J, et al. Molecular phylogeny of the cyprinid tribe Labeonini (Teleostei: Cypriniformes). Mol. Phylogenet. Evol. 2012;65(2): 362–379. pmid:22728909
- 3.
FAO. The State of World Fisheries and Aquaculture. 2022. Towards Blue Transformation: Rome; 2022. https://www.fao.org/3/cc0461en/cc0461en.pdf
- 4.
Arai R. Fish karyotypes: a check list. 1st ed.Springer Science & Business Media; 2011.
- 5. Phimphan S, Chaiyasan P, Suwannapoom C, Reungsing M, Juntaree S, Tanomtong A, et al. Comparative karyotype study of three Cyprinids (Cyprinidae, Cyprininae) in Thailand by classical cytogenetic and FISH techniques. Comp. Cytogenet. 2020;14(4):597. pmid:33384854
- 6. Yang L, Sado T, Hirt MV, Pasco-Viel E, Arunachalam M, Li J, et al. Phylogeny and polyploidy: resolving the classification of cyprinine fishes (Teleostei: Cypriniformes). Mol. Phylogenet. Evol. 2015;85: 97–116. pmid:25698355
- 7. Yang L, Naylor GJ, Mayden RL. Deciphering reticulate evolution of the largest group of polyploid vertebrates, the subfamily cyprininae (Teleostei: Cypriniformes). Mol. Phylogenet. Evol. 2022;166: 107323. pmid:34634450
- 8. Conway KW. Osteology of the South Asian Genus Psilorhynchus McClelland, 1839 (Teleostei: Ostariophysi: Psilorhynchidae), with investigation of its phylogenetic relationships within the order Cypriniformes. Zool. J. Lin. Soc. 2011;163: 50–154.
- 9. Stout CC, Tan M, Lemmon AR, Lemmon EM, Armbruster JW. Resolving Cypriniformes relationships using an anchored enrichment approach. BMC Evol. Biol. 2016;16: 1–13. pmid:27829363
- 10. Kim DS, Song HY, Bang IC, Nam YK. Cytogenetic analysis of Korean shinner, Coreoleuciscus splendidus (Cyprinidae). J. Aquac. 2007;20(2): 140–143.
- 11. Sola L, Gornung E. Classical and molecular cytogenetics of the zebrafish, Danio rerio (Cyprinidae, Cypriniformes): an overview. Genetica 2001;111: 397–412. pmid:11841183
- 12. Rábová M, Ráb P, Ozouf-Costaz C, Ene C, Wanzeböck J. Comparative cytogenetics and chromosomal characteristics of ribosomal DNA in the fish genus Vimba (Cyprinidae). Genetica 2003;118: 83–91. pmid:12733667
- 13. Libertini A, Sola L, Rampin M, Rossi A.R., Iijima K, Ueda T. Classical and molecular cytogenetic characterization of allochthonous European bitterling Rhodeus amarus (Cyprinidae, Acheilognathinae) from Northern Italy. Genes Genet. Syst. 2008;83(5): 417–422. pmid:19168992
- 14. Boron A, Porycka K, Ito D, Abe S, Kirtiklis L. Comparative molecular cytogenetic analysis of three Leuciscus species (Pisces, Cyprinidae) using chromosome banding and FISH with rDNA. Genetica 2009;135: 199–207. pmid:18473124
- 15.
Bishani A, Prokopov DY, Romanenko SA, Druzhkova AS, Interesova EA, Graphodatsky AS, et al. Repetitive DNA characterization in Cyprinid species with different ploidy level. In: Chromosomes and Mitosis (pp. 25–25). Russia: Novosibirsk National Research State University; 2019. pp. 25–25.
- 16. Aiumsumang S, Chaiyasan P, Khoomsab K, Supiwong W, Phim-phan ATS. Comparative chromosome mapping of repetitive DNA in four min-now fishes (Cyprinidae, Cypriniformes). Caryologia 2022;75(2): 71–80.
- 17. Saenjundaeng P, Kaewmad P, Supiwong W, Pinthong K, Pengseng P, Tanomtong A. Karyotype and characteristics of nucleolar organizer regions in longfin carp, Labiobarbus leptocheilus (Cypriniformes, Cyprinidae). Cytologia 2018;83(3): 265–269.
- 18. Saenjundaeng P, Supiwong W, Sassi FMC, Bertollo LAC, Rab P, Kretschmer R,. Chromosomes of Asian cyprinid fishes: Variable karyotype patterns and evolutionary trends in the genus Osteochilus (Cyprinidae, Labeoninae,“Osteochilini”). Genet. Mol. Biol. 2020;43: e20200195. pmid:33156892
- 19. Cioffi MB, Bertollo LAC. Chromosomal distribution and evolution of repetitive DNAs in fish. Genome Dyn. 2012;7: 197–221. pmid:22759820
- 20. Yüksel E, Gaffaroğlu M. The analysis of nucleolar organizer regions in Chalcalburnus mossulensis (Pisces: Cyprinidae). J. fish. Sci. 2008;2(4): 587–591.
- 21. Gromicho M, Ozouf-Costaz C, Collares-Pereira MJ. Lack of correspondence between CMA3-, Ag-positive signals and 28S rDNA loci in two Iberian minnows (Teleostei, Cyprinidae) evidenced by sequential banding. Cytogenet. Genome Res. 2005;109(4): 507–511. pmid:15905646
- 22. Knytl M, Kalous L, Symonová R, Rylková K, Ráb P. Chromosome studies of European cyprinid fishes: cross-species painting reveals natural allotetraploid origin of a Carassius female with 206 chromosomes. Cytogenet. Genome Res. 2013;139(4): 276–283. pmid:23652770
- 23. Kirtiklis L, Ocalewicz K, Wiechowska M, Boroń A, Hliwa P. Molecular cytogenetic study of the European bitterling Rhodeus amarus (Teleostei: Cyprinidae: Acheilognathinae). Genetica 2014;142: 141–148. pmid:24677088
- 24. Li S, Zhou Y, Yang C, Fan S, Huang L, Zhou T, et al. Comparative analyses of hypothalamus transcriptomes reveal fertility-, growth-, and immune-related genes and signal pathways in different ploidy cyprinid fish. Genomics 2021;113(2): 595–605. pmid:33485949
- 25. Gaffaroğlu M, Karasu-Ayata M, Unal-Karakus S. Karyomorphology of Two Cyprinid Barbels (Teleostei: Cyprinidae) from Gediz River, Turkey. Cytol. Genet. 2022;56: 41–547.
- 26. Kentachalee N, Pinthong K, Tongnunui S, Tanomtong A, Juntharat S, Supiwong W. First Report on Genetic Structure of Lobocheilos rhabdoura (Fowler, 1934) (Labeoninae, Cyprinidae) in Thailand: Insight the Basic Knowledge for Fish Breeding. FAST 2023;9: 90–103.
- 27.
Donsakul T, Rangsiruji A, Magtoon W. Karyotypes of five cyprinid fishes (Family Cyprinidae): Bangana devdevi, Osteobrama alfrediana, Systomus stoliczkanus, Oxygaster anomalura and Aspidoparia morar in Thailand. In: Proceedings of the 49th Kasetsart University Annual Conference: Fisheries. Thailand: Kasetsart University; 2011. pp. 169–177
- 28.
Donsakul T, Magtoon W, Rangsiruji A. Karyological studies of four Cyprinid fishes: Barbichthys nitidus, Mystacoleucus argenteus, Cychocheilichthys lagleri and Systomus sp. 1 from Thailand. In: Proceedings of the 44rd Kasetsart University Annual Conference: Fisheries. Thailand: Kasetsart University; 2006.
- 29. Magtoon W, Arai R. Karyotypes and distribution of nucleolus organizer regions in cyprinid fishes from Thailand. J. Ichthyol. 1993;40(1): 77–85.
- 30.
Donsakul T, Rangsiruji A, Magtoon W. Karyotypes of four cyprinid fishes: Poropuntius normani, Hypsibarbus malcolmi, Scaphognathops bandanensis and Henicorhynchus caudiguttatus from Thailand. In: Proceedings of the 45th Kasetsart University Annual Conference: Fisheries. Thailand: Kasetsart University; 2007. pp. 740–748.
- 31. Zhang JX, Liu XF, Wang ZX, Jin GQ. A comparative study on the karyotypes among the hybrid fish (Sinilabeo decorus tungting male × Cirrhinus molitorella female) and its parental fishes. Acta Hydrobiol. Sin. 1984;8: 313–320.
- 32. Gui JF, Li YC, Li K, Zhou T. Studies on the karyotype of Chinese cyprinid fish. (VII) Karyotypic analyses of fifteen species of Barbinae with consideration for their phyletic evolution. Transactions Chi. Ichthyol. Soc. 1986;5: 119–127.
- 33. Ren XH, Yu XJ. Characterization of nucleolar organizer regions of twelve species of Chinese cyprinid fishes. Caryologia 1993;46: 201–207.
- 34. Ren XH, Cui J, Yu Q. Chromosomal heterochromatin differentiation of cyprinid fishes. Genetica 1992;87: 47–51.
- 35.
Yu XJ, Zhou T, Li YC, Li K, Zhou M. Chromosomes of Chinese freshwater fishes. Science Publishing House: USA; 1989.
- 36. Lakra WS & Krishna G. G-banded karyotypes of three species of Indian major carps. CIS 1994;57: 23–25.
- 37. Rishi K.K. Chromosomal studies on four cyprinid fishes. Int. J. Acad. Ich. 1981;2: 1–4.
- 38. Nagpure NS, Kushwaha B, Srivastava SK, Ponniah AG. Comparative cytogenetic studies in Indian major carps Labeo rohita, Catla catla and Cirrhinus mrigala (Cyprinidae, Pisces). Chromosome Sci. 2001;5: 153–158.
- 39. Manna GK, Khuda-Bukhsh AR. Karyomorphology of cyprinid fishes and cytological evaluation of the family. Nucleus 1977;20: 119–127.
- 40. Khuda-Bukhsh AR, Rahman A, Chanda T, Nayak K, Khuda-Bukhsh A. Diploid numbers and chromosome formulae of some 29 species of Indian teleosts (Pisces). CIS 1995;58: 38–39.
- 41.
Chanda T. Aspidoparia morar, Chagunius chagunio, Crossocheilus latius latius, Mystus bleekeri, Mystus menoda menoda, Ailia coila, Clupisoma garua, Pseudeutropius atherinoides, Glyptothorax trilineatus, Laguvia rebeiroi, Nangra punctata, Johnius dussumieri, Colisa sota. In: Ponniah AG, John G, editors. Fish chromosome atlas. India: National Bureau of Fish Genetic Resources; 1998. pp. 22–23, 48–49, 58–59, 158–159, 164–165, 190–191, 192–193, 196–197, 208–213, 244–245, 286–287).
- 42. Tripathi NK, Sharma OP. Cytological studies on six cyprinid fishes. Genetica 1987;73: 243–246.
- 43. Lakra WS, Rishi KK. Chromosomes of Indian fishes: an annotated list. Indian J. Anim. Sci. 1991;61: 342–349.
- 44.
Donsakul T, Magtoon W. A chromosome study of three Cyprinid fishes, Labeo erythrurus, L. bicolor and L. rohita. In: Proceedings of the 31st Kasetsart University Annual Conference. Thailand: Kasetsart University; 1993.
- 45.
Donsakul T, Magtoon W, Rangsiruji A. Karyotypes of five cyprinid fishes (family Cyprinidae): Macrochirichthys macrochirus, Scaphiodonichthys acanthopterus, Epalzeorhynchos munensis, Opsarius koratensis and Parachela sp. from Thailand. In: Proceedings of the 50th Kasetsart University Annual Conference. Thailand: Kasetsart University; 2012. pp. 439–446.
- 46. Donsakul T, Runsiruji A, Magtoon W. Karyotypes of three species of cyprinid fishes Garra cambodgiensis, G. fasciacauda and G. notata (Cypriniformes, Cyprinidae) from Thailand. Knowl. Res. 2016;2(2): 30–35.
- 47. Suzuki A, Taki Y, Mochizuki M, Hirata J. Chromosomal speciation in Eurasian and Japanese Cyprinidae (Pisces, Cypriniformes). Cytobios 1995;83: 171–186.
- 48. Hinegardner R, Rosen DE. Cellular DNA content and the evolution of teleostean fishes. Am. Nat. 1972;106(951):621–644.
- 49. Krysanov EY, Golubtsov AS. Karyotypes of three Garra species from Ethiopia. J. Fish Biol. 1993;42(3):465–467.
- 50. Khuda-Bukhsh AR. Karyotype studies in two species of hill stream fishes, Labeo diplostomus and Garra gotyla gotyla (Pisces, Cyprinidae). Cytol. Genet. 1984;4:421–424.
- 51. Khuda-Bukhsh AR, Barat A. Chromosomes in fifteen species of Indian teleosts (Pisces). Caryologia 1987;40(1–2):131–144.
- 52. Sahoo PK, Nanda P, Barat A. Karyotypic Analysis of Neolissocheilus hexagonolepis (McClelland), Puntius ticto (Ham.) and P. chola (Ham.) (Family: Cyprinidae, Pisces). Cytologia 2007;72(4):409–413.
- 53. Li K, Li YC, Gui JF, Xie XZ, Zhou T. Studies on the karyotypes of Chinese cyprinid fishes. IX. Karyotypes of nine species of Abramidinae and one species of Xenocyprininae. Acta Hydrobiol. Sin. 1986;10:189–193.
- 54. Khuda-Bukhsh AR, Chanda T, Barat A. Karyomorphology and evolution in some Indian hillstream fishes with particular reference to polyploidy in some species. Indo-Pac. Fishes 1986; 886–898.
- 55. Khuda-Bukhsh AR, Gupta SK, Goswami S. Karyotypic studies in Garra lamta and Mystus cavassius (Pisces). J. Anim. Sci. 1980;89: 557–562.
- 56. Nagpure NS, Kumar R, Srivastava SK, Kushwaha B, Gopalakrishnan A, Basheer VS. Cytogenetic characterization of two marine ornamental fishes, Chaetodon collare and Stegastes insularis. J. Mar. Biol. Ass. 2006;48(2):267–269.
- 57. Guégan JF, Morand S. Polyploid hosts: strange attractors for parasites?. Oikos 1996;77(2):366–370.
- 58. Duran A, Barquinero JF, Caballín MR, Ribas M, Puig P, Egozcue J, et al. Suitability of FISH painting techniques for the detection of partial-body irradiations for biological dosimetry. Radiat. Res. 2002; 157(4):461–468. pmid:11893249
- 59. Olaoluwa PM, Idowu AI. Karyological Studies of Garra trewavasae Monod 1950 from Jos Plateau, Nigeria. Environtropica 2019;(15):120–128.
- 60. John G, Barat A, Lakra WS. 1993. Localization of nucleolar organizer regions in Labeo (Cyprinidae). La Kromosomo 1993;70:2381–2384.
- 61. Arai R, Magtoon W. Karyotypes of four cyprinid fishes from Thailand. Bull. Nat. Mus. Nat. Sci. 1991;17: 183–188.
- 62. Rishi KK, Rishi S. Giemsa banding in fish chromosomes. Cytol. Genet. 1981;3:103–106.
- 63. Rock J, Eldridge M, Champion A, Johnston P, Joss J. Karyotype and nuclear DNA content of the Australian lungfish, Neoceratodus forsteri (Ceratodidae: Dipnoi). Cytogenet. Cell Genet. 1996;73:187–189. pmid:8697805
- 64.
Seetapan K. Karyotypes of sex fish species of the family Cyprinidae. In: Proceedings of the 45th Kasetsart University Annual Conference: Fisheries. Thailand: Kasetsart University; 2007. pp. 749–758
- 65. Sărășan A, Józsa E, Ardelean AC, Drăguț L. Sensitivity of geomorphons to mapping specific landforms from a digital elevation model: A case study of drumlins. Area 2019;51(2):257–267.
- 66. Paugy D, Guégan JF, Agnèse JF. Three simultaneous and independent approaches to the characterization of a new species of Labeo (Teleostei, Cyprinidae) from West Africa. Can. J. Zoo. 1990;68:1124–1131.
- 67.
Khuda-Bukhsh AR, Chanda T. Somatic chromosomes of three species of hillstream fishes from Assam. In: Das P, Jhingran AG, editors. Fish genetics in India. Today & Tomorrow’s Printers and Publishers; 1989. pp. 69–73.
- 68. Kligerman AD, Bloom SE. Rapid chromosome preparations from solid tissues of fishes. J. Fish. Res. Board Can. 1977;34:266–269.
- 69. Nagpure NS, Kushwaha B, Srivastava SK, Kumar R, Gopalakrishnan A, Baseer VS, et al. Characterization of three endemic fish species from Western Ghats using cytogenetic markers. Nucleus 2003;46:110–114.
- 70. Rishi KK, Mandhan RP. Analysis of C-banded heterochromatin in the chromosomes of Labeo rohita (Ham.) (Cyprinidae). CIS 1990;48:3–4.
- 71. Magtoon W, Arai R. Karyotypes of three cyprinid fishes, Osteochilus hasselti, O. vittatus, and Labiobarbus lineatus, from Thailand. Japan. J. of Ichthyol. 1990;36:483–487.
- 72. Wang RF, He WS, Wu SF. Study on the karyotype and banding of Semilabeo prochilus (Pisces). Zool. Res. 1997;18:411–414.
- 73. Kulabtong S, Suksri S, Nonpayom C, Soonthornkit Y. Rediscovery of the critically endangered cyprinid fish Epalzeorhynchos bicolor (Smith, 1931) from West Thailand (Cypriniformes, Cyprinidae). Biodivers. J. 2014;5(2):371–373.
- 74. Phomikong P, Udduang S, Fukushima M, Srichareondham B, Rattanachamnong D, Jutagate T. Larval fish assemblage patterns in three tributaries of Mekong River in Thailand. Indian J. Fish. 2018;65(2):1–15.
- 75. Yang JX, Winterbottom R. Phylogeny and zoogeography of the cyprinid Genus Epalzeorhynchos Bleeker (Cyprinidae: Ostariophysi). Copeia 1998;1:48–63.
- 76. Kottelat M. The fishes of the inland waters of Southeast Asia: a catalogue and core bibliography of the fishes known to occur in freshwaters, mangroves and estuaries. Raffles Bull. Zool. 2013;27:1–663.
- 77.
Bertollo LAC, Cioffi MB, Moreira-Filho O. Direct chromosome preparation from freshwater teleost fishes. In: Ozouf-Costaz C, Pisano E, Foresti F, Toledo LFA, editors. Fish cytogenetic techniques: Ray-fin fishes and chondrichthyans. CRC Press; 2015. pp. 21–26.
- 78. Howell WM, Black DA. 1980. Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method. Experientia 1980;36:1014–1015. pmid:6160049
- 79.
Yano CF, Bertollo LAC, Cioffi MB. Fish-FISH: Molecular cytogenetics in fish species. In: Liehr T, editor. Fluorescence In Situ Hybridization (FISH). Springer; 2017. pp. 429–443.
- 80. Martins C, Ferreira IA, Oliveira C, Foresti F, Galetti PM. A tandemly repetitive centromeric DNA sequence of the fish Hoplias malabaricus (Characiformes: Erythrinidae) is derived from 5S rDNA. Genetica 2006;127:133–141. pmid:16850219
- 81. Cioffi MB, Martins C, Centofante L, Jacobina U, Bertollo LAC. Chromosomal variability among allopatric populations of Erythrinidae fish Hoplias malabaricus: Mapping of three classes of repetitive DNAs. Cytogene. Genome Res. 2009;125:132–141. pmid:19729917
- 82. Kubat Z, Hobza R, Vyskot B, Kejnovsky E. Microsatellite accumulation on the Y chromosome in Silene latifolia. Genome 2008;51:350–356. pmid:18438438
- 83. Levan A, Fredga K, Sandberg AA. Nomenclature for centromeric position on chromosomes. Hereditas 1964;52,:201–220.
- 84. Wolf U, Ritter H, Atkin NB, Ohno S. Polyploidization in the fish family Cyprinidae, order Cypriniformes. Humangenetik 1969;7:240–244.
- 85. Gerbi SA. The evolution of eukaryotic ribosomal DNA. Biosyst. 1986;19(4):247–258. pmid:3026507
- 86. Sochorová J, Garcia S, Gálvez F, Symonová R, Kovařík A. Evolutionary trends in animal ribosomal DNA loci: Introduction to a new online database. Chromosoma 2018;127:141–150. pmid:29192338
- 87. Khensuwan S, Sassi FMC, Moraes RLR, Jantarat S, Seetapan K, Phintong K, et al. Chromosomes of Asian Cyprinid Fishes: Genomic Differences in Conserved Karyotypes of ‘Poropuntiinae’ (Teleostei, Cyprinidae). Animals 2023;13(8):1415. pmid:37106978
- 88.
White MJD. Animal cytology and evolution. 3rd ed. England: Cambridge University Press; 1973.
- 89. Hoffmann AA, Rieseberg LH. Revisiting the impact of inversions in evolution: from population genetic markers to drivers of adaptive shifts and speciation?. Annu. Rev. Ecol. Evol. Syst. 2008;39:21–42. pmid:20419035
- 90. Kirkpatrick M. How and why chromosome inversions evolve. PLoS Biol. 2010;8(9):e1000501. pmid:20927412
- 91. Charlesworth B, Barton NH. The spread of an inversion with migration and selection. Genetics 2018; 208(1):377–382. pmid:29158424
- 92. Wellenreuther M, Bernatchez L. Eco-evolutionary genomics of chromosomal inversions. Trends Ecol. Evol. 2018;33(6):427–440. pmid:29731154
- 93. Terêncio ML, Schneider CH, Gross MC, Vicari MR, Farias IP, Passos KB, et al. Evolutionary dynamics of repetitive DNA in Semaprochilodus (Characiformes, Prochilodontidae): a fish model for sex chromosome differentiation. Sex. Dev. 2013;7(6):325–333. pmid:24296872
- 94. Yano CF, Poltronieri J, Bertollo LAC, Artoni RF, Liehr T, B Cioffi M. Chromosomal mapping of repetitive DNAs in Triportheus trifurcatus (Characidae, Characiformes): insights into the differentiation of the Z and W chromosomes. PLoS One 2014;9(3):e90946. pmid:24632562
- 95. Cioffi MB, Bertollo LAC, Villa MA, de Oliveira EA, Tanomtong A, Yano CF, et al. Genomic organization of repetitive DNA elements and its implications for the chromosomal evolution of channid fishes (Actinopterygii, Perciformes). PLoS One 2015;10(6):e0130199. pmid:26067030
- 96. Moraes RLR, Bertollo LAC, Marinho MMF, Yano CF, Hatanaka T, Barby FF, et al. Evolutionary relationships and cytotaxonomy considerations in the genus Pyrrhulina (Characiformes, Lebiasinidae). Zebrafish 2017;14(6):536–546. pmid:28767325
- 97. Moraes RLR, Sember A, Bertollo LAC, De Oliveira EA, Ráb P, Hatanaka T, et al. Comparative cytogenetics and neo-Y formation in small-sized fish species of the genus Pyrrhulina (Characiformes, Lebiasinidae). Front. Genet. 2019;10: 678. pmid:31428127
- 98. Sassi FMC, de Oliveira EA, Bertollo LAC, Nirchio M, Hatanaka T, Marinho MMF, et al. Chromosomal evolution and evolutionary relationships of Lebiasina species (Characiformes, Lebiasinidae). Int. J. Mol. Sci. 2019;20(12):2944. pmid:31208145
- 99. Ellegren H. Evolutionary stasis: the stable chromosomes of birds. Trends Ecol. Evol. 2010;25(5):283–291. pmid:20363047
- 100. Zhang X, Zhang S, Zhao Q, Ming R, Tang H. Assembly of allele-aware, chromosomal-scale autopolyploid genomes based on Hi-C data. Nat. plants 2019;5(8):833–845. pmid:31383970
- 101. Hong Y, Zhou T. Studies on the karyotype and C-banding patterns in Acheilognathus gracilis with a discussion on the evolution of acheilognathid fishes. Act. Gen. Sin. 1985;12:143–148.
- 102. Yu XY, Yu XJ. A schizothoracine fish species, Diptychus dipogon, with a very high number of chromosomes. CIS 1990;48:17–18.