Study Of Microsatellite Markers On Genetic Characteristic Of The Multiple Pengze Crucian Carp

Known as gynogenetic crucian carp in China, Pengze crucian carp (Carassiusauratus of Pengze) is an endemic bisexual population with natural gynogeneticreproduction mode. The multiple pengze crucian carp is the minority of the offspringof Pengze crucian carp activated by heterogenous sperm, and possesses some obviouspatrilineal characteristics, such as the body form, color, the length of rostrum and thecolor of the lateral scales and so on. There are two different types in multiple pengzecrucian carp: The chromosome number of one group is 206, exactly the summation ofthe total chromosome number (156) of the maternal pengze crucian carp and thehaploid chromosome number (50) of the paternal sharpfin carp(Cyprinusacutidorsalis), we called them multiple tetraploid allogynogenetic pengze cruciancarp (in this paper, multiple tetraploid form in short); DNA content of the other groupwere between triploid and tetraploidy, we called them aneuploid multiple pengzecrucian carp (in this paper, aneuploid form in short). The phenomenon that two typesexisted in multiple pengze crucian carp has important meanings for further studies onthe mechanism underlying allogynogenesis.In the thesis, microsatellite variation among the multiple pengze crucian carp andits parents were anasyzed; the two offsprings of the multiple tetraploid form, activatedby homologous and heterogenous sperm respectively, were studied by SSR. Thepossible mechanism of creation of the multiple tetraploid form and aneuploid form aswell as the development mode of multiple tetraploid allogynogenetic pengze cruciancarp were discussed.The results showed that: (1) The multiple tetraploid form and sharpfin carp hadsome identical DNA fragments, these were detected in part of aneuploid form and innone of the pengze crucian carp; The genetic similarity index between aneuploid form,multiple tetraploid form and their female parent pengze crucian carp was much higher(0.87 and 0.83)than with male parent sharpfin carp (0.42 and 0.48), whereas the latter was much higher than the genetic similarity between their parents(0.322); Thephylogenetic tree showed that the multiple pengze crucian carp and pengze cruciancarp were in the same group, which indicated a near phylogenetic relationship; whilethe sharpfin carp was in the other group; (2) The two offsprings of the multipletetraploid allogynogenetic pengze crucian carp, activated by maternal (Carassiusauratus of Pengze) and paternal (Cyprinus acutidorsalis) sperm respectively, mostlyamplified the identical band patterns with their female parent; The genetic similarityindex between the two offsprings and their female parent multiple tetraploid form(0.96 and 0.98)was obviously higher than with their male parent(0.49 and 0.822),whereas the latter was almost the same as the genetic similarity between their femaleparent and two kinds of male parents (0.5 and 0.820).The above results suggested that: (1) The multiple tetraploid form preserved allof the chromosomes of pengze crucian carp and also contained the paternal haploidchromosomes of the sharpfin carp, while the insert of the haploid genome of agnatewas instable, had some random drops, accordingly a few aneuploid form appeared inthe offersprings. (2) The multiple tetraploid allogynogenetic pengze crucian carpinherited the characteristic of gynogenesis from its female parent (Carassius auratusof Pengze), basically, sperms had few contribution to the heredity.The multiple tetraploid allogynogenetic pengze crucian carp possesses specialsignificance to the research of the monosexual, especially bisexual fish. It is not onlyone favorable material to research the mechanism of gynogenesis, but also havetremendous potential on breeding.