Sturgeon species (order Acipenseriformes) are prone for interspecific hybridization. Anthropogenic activities in river basins influence sturgeon reproduction by destruction of their natural spawning grounds. Consequently, spawning areas, as well as the time of spawning of sturgeon species overlap and different sturgeon species reproduce concurrently. This increases the probability of meeting of heterospecific gametes and pre-zygotic postcopulatory reproductive barriers, comprising of sperm competition and cryptic female choice, may play an important role in preventing undesirable interspecific hybridization. The goal of this study was to evaluate the role of interspecific sperm competition and cryptic female choice during interspecific hybridization of sterlet (Acipenser ruthenus) and Siberian sturgeon (Acipenser baerii). Reproductive characteristics (fertilization rate and hatching rate) were described in each of experimental and control groups showing similar values for competitive and non-competitive trials. Parentage assignment was performed in hatched larvae using combination of mitochondrial DNA and microsatellite DNA markers. Obtained results revealed higher fertilization success of sterlet spermatozoa, when these competed for fertilization with spermatozoa of Siberian sturgeon. Total reproductive success of starlet spermatozoa was 78.9 % and Siberian sturgeon 21.1 %. Contrary, when spermatozoa did not compete for fertilization, males of analysed species showed equal fertilization success. In the trials, where eggs of both studied species were mixed and fertilized by sperm from each species separately, eggs of any species did not show a tendency to bias fertilization by spermatozoa of conspecific males. Probably, there are no pre-zygotic postcopulatory reproductive barriers that prevent interspecific hybridization of sterlet and Siberian sturgeon at the gametic level.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:253071 |
| Date | January 2016 |
| Creators | ŠACHLOVÁ, Hana |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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