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Somatic cell nuclear transfer in cattle
Abstract
The development of somatic nuclear transfer procedures and the factors that are likely to affect the success of nuclear transplantation were discussed in the first chapter. In chapter 2, the effects of cell cycle stage and age of the cell donor animal on in vitro development of bovine nuclear transfer embryos were investigated. Cultures of primary bovine fibroblasts were established from animals of various ages and the in vitro life span of these cell lines were analyzed. The cell cycle characteristics of both fetal and adult cells were analyzed as a population of cells in culture. To study the individual cells from a population, a “shake off” method was developed to isolate G1 cells and evaluate progression through cell cycle. Irrespective of the age of the cell donor, the mean cell cycle length in isolated cells was shorter than what was observed for cells cultured as a population. In vitro development was analyzed after fusing confluent and isolated G1 cells to enucleated metaphase II oocytes. These results indicate that there were no differences in either the number of cells in blastocysts or the percentage of blastocysts between the embryos reconstructed with G1 cells and confluent cells. Because previous studies do not clearly demonstrate the cell cycle stage of the donor cell that resulted in development to term, Chapter 2 evaluates the methods of producing populations of G0 and G1 cells and the cell cycle characteristics of G0 and G1 cells. Furthermore, in vitro and in vivo development of embryos derived from high confluent, G0 cells and “shake off” G1 cells were evaluated. These results indicate that the isolated G1 cells supported development to term better than confluent cells. Finally, in Chapter 3, pregnancy establishment, pregnancy loss and health of newborn calves were evaluated for nuclear transfer embryos derived from cells of different genotypes from dairy and beef breeds. In addition, the effect of overnight shipping of cloned embryos and the synchrony between the age of the embryo and the estrus cycle of the recipient female on development were assessed. The results indicate that genotype has an effect on development of nuclear transfer embryos.
Subject Area
Cellular biology|Veterinary services
Recommended Citation
Kasinathan, Poothappillai, "Somatic cell nuclear transfer in cattle" (2002). Doctoral Dissertations Available from Proquest. AAI3039366.
https://scholarworks.umass.edu/dissertations/AAI3039366