Latest Articles from Acta Ichthyologica et Piscatoria Latest 3 Articles from Acta Ichthyologica et Piscatoria https://aiep.pensoft.net/ Thu, 28 Mar 2024 17:49:58 +0200 Pensoft FeedCreator https://aiep.pensoft.net/i/logo.jpg Latest Articles from Acta Ichthyologica et Piscatoria https://aiep.pensoft.net/ Triploid forms’ karyotypes of spined loaches from the genus Cobitis (Actinopterygii: Cypriniformes: Cobitidae) of the upper Dnieper and Western Dvina rivers: Analysis of the triploids’ origin https://aiep.pensoft.net/article/81191/ Acta Ichthyologica et Piscatoria 52(1): 67-75

DOI: 10.3897/aiep.52.81191

Authors: Victor Vasil`ev, Ekaterina Vasil`eva

Abstract: Unisexual forms of lower vertebrates (fish, amphibians, and reptiles) reproduced by parthenogenesis, gynogenesis, or hybridogenesis are represented by diploids, triploids, or tetraploids, whose origin is associated with interspecific hybridization. Among fish species, the highest variability of unisexual polyploids was found in the genus Cobitis. The structure of their genomes and putative parental species holds great interest for the investigation in association with questions about possible evolutionary success. In particular, it serves to elucidate the possible high colonization properties of a few polyploid forms, in contrast to the local history of rather numerous hybrid forms with a limited distribution. Therefore, the aim of this study was to describe the karyotype structure of two newly discovered triploid forms of the genus Cobitis, to analyze their origin and putative parental species. The karyotype structure of 182 spined loach individuals from the Western Dvina River and 91 individuals from the upper Dnieper River of the Smolensk District of Russia was studied. A total of 121 studied individuals from the Western Dvina comprised triploid females with a chromosome number 74 and karyotype consisting of 13 meta-, 39 submeta-, and 22 subtelo-acrocentric chromosomes. Among loaches collected in the upper Dnieper River, 42 triploid females were found with 74 chromosome number including 23 meta-, 26 submeta-, and 25 subtelo-acrocentric chromosomes. Other individuals from both localities were karyologically identified as Cobitis taenia Linnaeus, 1758 with 2n = 48. The triploid form of spined loaches of the Western Dvina River most likely arose as a result of the hybridization of Cobitis tanaitica Bǎcescu et Mayer, 1969 and C. taenia. The range of C. tanaitica, whose karyotype is characterized by an evolutionarily fixed Y-autosomal translocation, is limited to the rivers of the northern coast of the Black Sea. Therefore, hybridization probably happened in late Pleistocene in the Dnieper River system, where both parental species occur. The triploid form that arose here is unique for the Baltic Sea basin. Probably, it colonized the Western Dvina through the artificial Berezinskaya water system (Berezina Canal = Daugava–Dnieper Canal), but at the same time it was forced out of its area of origin by other triploid forms which are now widespread there. According to the karyotype structure, the triploid form, common for both the upper and lower reaches of the Dnieper, has a trihybrid origin, with probable hybridization of Cobitis elongatoides Bǎcescu et Mayer, 1969, C. tanaitica, and yet unidentified species Cobitis sp. Both studied triploid forms are parts of unisexual-bisexual complexes, in which their putative diploid maternal species (C. tanaitica and C. elongatoides) are absent, and the role of the host species involved in reproduction belongs to C. taenia.

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Research Article Tue, 29 Mar 2022 22:10:08 +0300
Non-invasive ploidy determination in live fish by measuring erythrocyte size in capillaries https://aiep.pensoft.net/article/65718/ Acta Ichthyologica et Piscatoria 51(3): 275-280

DOI: 10.3897/aiep.51.65718

Authors: Karel Halačka, Karel Janko, Lukáš Vetešník

Abstract: Information about ploidy is important in both commercial and conservation aquaculture and fish research. Unfortunately, methods for its determination, such as karyology, determination of the amount of DNA in a cell using microdensitometry or flow cytometry and/or measuring erythrocytes in a blood smear can be stressful or even destructive. Some of these methods are also limited by the relatively large minimum size of the individual being measured. The aim of this study was to test a new low-stress method of determining ploidy by measuring the size of erythrocytes in the capillaries of a fish, including small individuals. First, we examined diploid and triploid loach (Cobitis sp.) and gibel carp, Carassius gibelio (Bloch, 1782), using flow cytometry and blood smears, with these results being used as a control. Subsequently, we measured the size of erythrocytes in the caudal fin capillaries of anesthetized fishes of known ploidy under a light microscope. For both the loaches and gibel carp, direct observation of the mean erythrocyte size in epithelial fin capillaries provided a consistent and reliable determination of ploidy when compared with the controls based on flow cytometry and blood smears. This new method allows for rapid determination of ploidy in living small fish, where collection of tissue using other methods may cause excessive stress or damage. The method outlined here simply requires the measurement of erythrocytes directly in the bloodstream of a live fish, thereby making it possible to determine ploidy without the need for blood sampling. The method described is sufficiently efficient, less demanding on equipment than many other procedures, can be used by relatively inexperienced personnel and has benefits as regards animal welfare, which is especially important for fish production facilities or when dealing with rare or endangered species.

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Research Article Thu, 9 Sep 2021 09:55:50 +0300
Cross-species amplification of microsatellites and identification of polyploid hybrids by allele dosage effects in Cobitis hankugensis × Iksookimia longicorpa hybrid complex (Actinopterygii: Cypriniformes: Cobitidae) https://aiep.pensoft.net/article/63591/ Acta Ichthyologica et Piscatoria 51(2): 167-174

DOI: 10.3897/aiep.51.63591

Authors: Seung-Woon Yun, Jong-Young Park, Karel Janko

Abstract: During the course of evolution, numerous taxa abandoned canonical sex and reproduced asexually. Examination of the Cobitis hankugensis × Iksookimia longicorpa asexual complex already revealed important evolutionary discoveries tackling phenomena like interspecific hybridization, non-Mendelian inheritance, polyploidy, and asexuality. Yet, as in other similar cases, the investigation is hampered by the lack of easily accessible molecular tools for efficient differentiation among genomotypes. Here, we tested the cross-species amplification of 23 microsatellite markers derived from distantly related species and investigated the extent to which such markers can facilitate the genome identification in the non-model hybrid complex. We found that 21 out of 23 microsatellite markers were amplified in all genomotypes. Five of them could be used for easy diagnostics of parental species and their hybrids due to species-specific amplification profiles. We also noted that three markers, i.e., IC654 and IC783 derived from Cobitis choii Kim et Son, 1984 and Iko_TTA01 from Iksookimia koreensis (Kim, 1975), had dosage-sensitive amplification efficiencies of species-specific alleles. This could be further used for reliable differentiation of genome composition in polyploids. The presently reported study introduces a noninvasive method applicable for the diagnosis of ploidy and genome composition of hybrids, which are not clearly distinguished morphologically. We showed that very detailed information may be obtained even from markers developed in distantly related taxa. Hybridization is being increasingly recognized as a driving force in evolution. Yet, proper detection of hybrids and their ploidy is particularly challenging, especially in non-model organisms. The present paper evaluates the power of microsatellite cross-amplification not only in the identification of hybrid forms but also in estimating their genome dosage on an example of a fish taxon that involves asexuality, hybridization as well as ploidy variation. It thus demonstrates the wide applicability of such cheap and non-invasive tools.

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Research Article Mon, 12 Jul 2021 10:13:11 +0300