Genetic diversity of diploid and triploid Carassius gibelio (Bloch, 1782) from bisexual population

Abstract

Event Abstract Back to Event Genetic diversity of diploid and triploid Carassius gibelio (Bloch, 1782) from bisexual population Karolina Kowalewska1*, Anna Przybył1, Natalia Jędrzejewska1, Edyta Kurantowicz1 and Alicja Boron1, 2 1 Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Poland 2 University of Warmia and Mazury in Olsztyn, Poland The silver crucian carp Carassius gibelio is a cyprinid (Cyprinidae) species living in almost all available water bodies as it is the most invasive freshwater species in Europe (Tóth et al. 2005; Grabowska and Przybylski 2015). It spread due to its enormous resistance to adverse environmental conditions, plasticity of reproduction and the possibility of creating viable, better adopted hybrids. It reproduces sexually and clonally, through gynogenesis; females lay eggs, which are stimulated to develop by the sperm of males, including related species (Zhang et al. 2015). This species is an interesting object of research, also due to recently reported changes in the sex and ploidy structure occurring in its populations. Initially, in Europe, unisexual populations, consisting of triploid (3n) gynogenetic females were dominated. Recently, however, more diploid-triploid populations have been described with varying numbers of diploid and sometimes triploid males (Vetemaa et al. 2005; Šlimková et al. 2015). This trend is also visible in Poland, where females with single males and bisexuals populations were recorded (Boroń et al. 2011; Szabelska et al. 2017). The causes of changes in the sex ratio and the associated reproduction in C. gibelio populations are not precisely understood. Genetic diversity plays an important role in the survival of species, populations and in their response to environmental changes. Relatively large differences in the genetic variability of the C. gibelio populations can be explained by the dominance of different modes of reproduction (Zhigileva et al. 2015). For this reason, this preliminary study aimed to compare the genetic diversity of C. gibelio diploid and triploid males and females inhabiting the diploid-polyploid population in the Siemianówka Reservoir. This population is interesting because of the unclear origin of 3n males and also because of the lack of knowledge about the reproduction of triploids individuals. Materials for investigation, fin or muscle tissues were taken 10 each from diploid and triploid females and males. Animals were treated in accordance with the Act of 15 January 2015 on the protection of animals for scientific and educational purposes, according to the opinion (No. 20/2013/N) of the Local Ethics Committee of the University of Warmia and Mazury in Olsztyn, Poland. Genetic diversity was analyzed by random amplification of polymorphic DNA fragments (RAPD) and by microsatellite markers. The DNA was extracted with the modified phenol-chloroform method using a urea buffer and a phenol-chloroform-isoamyl alcohol mixture (24:25:1). Ten primers selected were tested as the most useful for the C. gibelio genetic diversity using the RAPD method (Tóth et al. 2005; Dong et al. 2013). Among them, we managed to achieve effective amplification for five primers at 52 °C. The ZJ6 starter was characterized by the biggest differentiation of obtained banding DNA profiles, but starters AR5 and ZJ7 also maintained a high diversity of obtained profiles. Some individuals were characterized by the similarity of the obtained RAPD profile. However, in order to be considered as clonal lines, it was necessary to conduct further analyzes using more specific molecular markers. Amplification of microsatellite markers was carried out using multiplex PCR with universal fluorochrome labeled primers (Li et al. 2017). The conducted research confirmed the high efficiency of amplification of the 16 microsatellite markers used. The obtained products were subjected to capillary electrophoresis in the ABI3130xl sequencer (Applied Biosystem) using the GeneScan LIZ-500 marker. All the loci were polymorphic, and a total of 148 alleles were identified. The most polymorphic was GF19 (14 alleles), while the MFW2 was the less polymorphic (three alleles). The lengths of the ranges for the tested primers and the number of alleles deviated from the literature data, but these differences may result primarily from species and population differences and the presence of C. gibelio hybrids. The relatively large genetic diversity of the triploid C. gibelio males demonstrated, seems to be confirmed by literature data indicating the possibility of sexual reproduction between triploid females and males. The obtained results using microsatellite sequences require comparison with similar data of progeny from experimental crosses between diploid and triploid C. gibelio females and males. The presented data will be used in planning further experiments. Acknowledgements We express our thanks to the Polish Angling Association in Bialystok and Mr. Andrzej Filinowicz for collecting fish and to Dr. Anna Leska for collected tissue. This work was carried out within the projects no. 12.610.006-300 and 12.620.029-500 of the UWM in Olsztyn, financed by Ministry of Science and Higher Education, Poland.