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Can evolutionary diploid genome of tetraploid sturgeon species maintain the functional properties of the normal diploid genome?тезисы доклада
- Авторы: Vasil’ev V.P., Medvedev D.A., Rachek E.I., Amvrosov D.Yu, Mugue N.S., Barmintseva A.E., Vasil’eva Е.D.
- Сборник: Генетика популяций: прогресс и перспективы. Материалы Международной научной конференции, посвященной 80-летию со дня рождения академика Ю.П. Алтухова (1936-2006) и 45-летию основания лаборатории плопуляционной генетики им. Ю.П. Алтухова ИОГен РАН
- Тезисы
- Год издания: 2017
- Место издания: Ваш Формат Москва
- Первая страница: 50
- Последняя страница: 51
- Аннотация: The family Acipenseridae includes three genera - Acipenser (together with Huso), Scaphirhynchus, and Pseudoscaphirhynchus, which are represented by 25 species. The beginning of their evolution goes back to the Triassic, i.e. 245-208 millions years ago. During this period, they have passed through several separated in time acts of polyploidization, which resulted in the origin of three groups of species with different ploidy levels: diploids (8 species) with chromosome numbers about 120, tetraploids with 250-270 chromosomes, and the only hexaploid species with chromosome number about 372. However, according to some indirect data, 120-chromosome species have tetraploid origin (see Vasil'ev, 2009). Recently obtained convincing data prove that sterlet sturgeon (2n = 120) is a segmental tetraploid (Romanenko et al., 2016). Thus, considering tetraploid origin for 120-chromosome sturgeon species, the ploidy levels in these fishes should increased twice, namely tetraploids (120 chromosomes), octoploids (250-270 chromosomes), and didekaploids (372 chromosomes). In this connection, it was proposed to use two scales of ploidy levels in sturgeons (Vasil'ev, 2009): a recent scale (2n - 4n - 6n) and evolutionary scale (4n - 8n - 12n), whereby 120-chromosome species are evolutionary tetraploids, and thus the level of ploidy increases. At the same time, a number of multi-chromosome species (250-270 chromosomes) has an independent polyploid origin due to parallel acts of polyploidization. The problem posed in the title, and its solution, are associated with the study of fertile hybrid females obtained from sturgeon species with different ploidy levels: female of sterlet Acipenser ruthenus Linnaeus, 1758 (2n = 120) (S) x male of kaluga sturgeon A. dauricus Georgi, 1775 (2n≈264-270) (K). To determine the causes of fertility of one of SxK females we conducted microsatellite and cytometric analyses. The data show that the genome of this female originated by fertilization of the spontaneously diploidizated egg from sterlet. As a result, the genome of SxK hybrid does not contain the amount of haploid sets of sterlet and kaluga (190 chromosomes), as expected, but includes diploid genome from sterlet and haploid set of kaluga (about 260 chromosomes). The back-cross SxK x S hybrids had a chromosome number about 185, i.e. hybrid females produced the eggs with about 125 chromosomes. In this regard, it is believed that in meiosis 120 chromosomes from sterlet form 60 bivalents, and 130 chromosomes from kaluga form about 65 bivalents. This pattern of meiosis is also confirmed by the microsatellite analysis. Individuals from the offspring of this female obtained after insemination of its eggs by inactivated sperm (without fertilization) had about 125 chromosomes. This result is very interesting because the progeny with the genome consisting of haploid chromosome set from sterlet + a quarter of the genome (in this case evolutionary haploid set) from kaluga is viable. This is another good sign that cytogenetic and molecular evolution of sturgeon is a very slow process. Herewith, here we have integral evaluation, unlike the previously obtained estimates for individual molecular markers. Indeed, the tetraploid species of sturgeon appeared at least 100 Mya (judging from the chronology of Gondwana decay), and the time of the divergence of the genomes of sterlet and kaluga sturgeons, according to the method of molecular clock, is about 125 million years (Peng et al., 2007).
- Добавил в систему: Васильева Екатерина Денисовна