The disease progression of neurodegenerative disorders (NDD), including Alzheimer's, Parkinson's and Huntington's disease, is inextricably tied to mitochondrial dysfunction. However, although the contribution by nuclear gene mutations is recognised for familial onset of NDD, the degree to which cytoplasmic inheritance serves as a predetermining factor for the predisposition and onset of NDD is not yet fully understood. We review the reproductive mechanisms responsible for ensuring a healthy mitochondrial population within each new generation and elucidate how advanced maternal age can constitute an increased risk for the onset of NDD in the offspring, through the increased heteroplasmic burden. On the one hand, this review draws attention to how assisted reproductive technologies (ART) can impair mitochondrial fitness in offspring. On the other hand, we consider qualified ART approaches as a significant tool for the prevention of NDD pathogenesis.

• MeSH
• cvičení MeSH
• lidé MeSH
• mitochondrie genetika   MeSH
• neurodegenerativní nemoci * genetika   MeSH
• progrese nemoci MeSH
• rozmnožování MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

In pigs, in vitro production is difficult with a high occurrence of polyspermy and low blastocyst formation rates. To test the hypothesis that this may, at least in part, be due to chromosomal errors, we employed whole genome amplification and comparative genomic hybridization, performing comprehensive chromosome analysis to assess both cells of the two-cell stage in vitro porcine embryos. We thus described the incidence, nature and origin of chromosome abnormalities, i.e. whether they derived from incorrect meiotic division during gametogenesis or aberrant mitotic division in the zygote. We observed that 19 out of 51 (37%) of two-cell stage early pig IVP embryos had a chromosome abnormality, mostly originating from an abnormal division in the zygote. Moreover, we frequently encountered multiple aneuploidies and segmental chromosome aberrations. These results indicate that the pig may be particularly sensitive to in vitro production, which may, in turn, be due to incorrect chromosome segregations during meiosis and early cleavage divisions. We thus accept our hypothesis that chromosome abnormality could explain poor IVP outcomes in pigs.

• Klíčová slova
• Aneuploidy, Comparative genomic hybridization, Embryo, Pig,
• MeSH
• aneuploidie MeSH
• chromozomální aberace * MeSH
• embryo savčí MeSH
• fertilizace in vitro veterinární   MeSH
• srovnávací genomová hybridizace MeSH
• Sus scrofa embryologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mammalian female gametes frequently suffer from numerical chromosomal aberrations, the main cause of miscarriages and severe developmental defects. The underlying mechanisms responsible for the development of aneuploidy in oocytes are still not completely understood and remain a subject of extensive research. From studies focused on prevalence of aneuploidy in mouse oocytes, it has become obvious that reported rates of aneuploidy are strongly dependent on the method used for chromosome counting. In addition, it seems likely that differences between mouse strains could influence the frequency of aneuploidy as well; however, up till now, such a comparison has not been available. Therefore, in our study, we measured the levels of aneuploidy which has resulted from missegregation in meiosis I, in oocytes of three commonly used mouse strains-CD-1, C3H/HeJ, and C57BL/6. Our results revealed that, although the overall chromosomal numerical aberration rates were similar in all three strains, a different number of oocytes in each strain contained prematurely segregated sister chromatids (PSSC). This indicates that a predisposition for this type of chromosome segregation error in oocyte meiosis I is dependent on genetic background.

• MeSH
• aneuploidie MeSH
• chromatidy genetika   MeSH
• meióza genetika   MeSH
• myši inbrední C3H MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• oocyty cytologie   MeSH
• počet buněk MeSH
• polární tělísko metabolismus   MeSH
• segregace chromozomů genetika   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chromosome segregation errors are highly frequent in mammalian female meiosis, and their incidence gradually increases with maternal age. The fate of aneuploid eggs is obviously dependent on the stringency of mechanisms for detecting unattached or repairing incorrectly attached kinetochores. In case of their failure, the newly formed embryo will inherit the impaired set of chromosomes, which will have severe consequences for its further development. Whether spindle assembly checkpoint (SAC) in oocytes is capable of arresting cell cycle progression in response to unaligned kinetochores was discussed for a long time. It is known that abolishing SAC increases frequency of chromosome segregation errors and causes precocious entry into anaphase; SAC, therefore, seems to be essential for normal chromosome segregation in meiosis I. However, it was also reported that for anaphase-promoting complex (APC) activation, which is a prerequisite for entering anaphase; alignment of only a critical mass of kinetochores on equatorial plane is sufficient. This indicates that the function of SAC and of cooperating chromosome attachment correction mechanisms in oocytes is different from somatic cells. To analyze this phenomenon, we used live cell confocal microscopy to monitor chromosome movements, spindle formation, APC activation and polar body extrusion (PBE) simultaneously in individual oocytes at various time points during first meiotic division. Our results, using oocytes from aged animals and interspecific crosses, demonstrate that multiple unaligned kinetochores and severe congression defects are tolerated at the metaphase to anaphase transition, although such cells retain sensitivity to nocodazole. This indicates that checkpoint mechanisms, operating in oocytes at this point, are essential for accurate timing of APC activation in meiosis I, but they are insufficient in detection or correction of unaligned chromosomes, preparing thus conditions for propagation of the aneuploidy to the embryo.

• MeSH
• anafáze MeSH
• anafázi podporující komplex MeSH
• aneuploidie MeSH
• časosběrné zobrazování metody   MeSH
• histony genetika   metabolismus   MeSH
• kinetochory metabolismus   MeSH
• komplexy ubikvitinligas genetika   metabolismus   MeSH
• konfokální mikroskopie metody   MeSH
• kontrolní body M fáze buněčného cyklu MeSH
• metafáze MeSH
• mikroinjekce MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• oocyty cytologie   metabolismus   MeSH
• párování chromozomů * MeSH
• proteolýza MeSH
• savčí chromozomy genetika   metabolismus   MeSH
• savci MeSH
• segregace chromozomů * MeSH
• sekurin MeSH
• transportní proteiny genetika   metabolismus   MeSH
• tubulin genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• anafázi podporující komplex MeSH
• histony MeSH
• komplexy ubikvitinligas MeSH
• sekurin MeSH
• transportní proteiny MeSH
• tubulin MeSH

Data on the frequency of aneuploidy in farm animals are lacking and there is the need for a reliable technique which is capable of detecting all chromosomes simultaneously in a single cell. With the employment of comparative genomic hybridization coupled with the whole genome amplification technique, this study brings new information regarding the aneuploidy of individual chromosomes in pigs. Focus is directed on in vivo porcine blastocysts and late morulas, 4.7% of which were found to carry chromosomal abnormality. Further, ploidy abnormalities were examined using FISH in a sample of porcine embryos. True polyploidy was relatively rare (1.6%), whilst mixoploidy was presented in 46.8% of embryos, however it was restricted to only a small number of cells per embryo. The combined data indicates that aneuploidy is not a prevalent cause of embryo mortality in pigs.

• MeSH
• aneuploidie * MeSH
• blastocysta cytologie   metabolismus   fyziologie   MeSH
• embryo savčí MeSH
• gestační stáří MeSH
• nemoci prasat diagnóza   embryologie   genetika   MeSH
• oocyty cytologie   metabolismus   fyziologie   MeSH
• prasata genetika   MeSH
• srovnávací genomová hybridizace metody   veterinární   MeSH
• těhotenství MeSH
• ztráta embrya diagnóza   genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH