Submitted to: Colloquium on Domestic Animal Cytogenetics and Gene Mapping
Publication Type: Proceedings
Publication Acceptance Date: 6/12/2006
Publication Date: 6/22/2006
Citation: Pinton, A., Favetta, L.A., Coppola, G., Ducos, A., Powell, A.M., Wall, R.J., King, W.A. 2006. Cytological and molecular analysis of normal and cloned bulls’ meiosis. Colloquium on Domestic Animal Cytogenetics and Gene Mapping. Interpretive Summary:
Technical Abstract: Cytological and molecular analysis of meiotic cells from two bull clones and three non-clones was performed in order to detect effects of somatic cell nuclear transfer (SNCT) on the meiotic process. Pachytene cells were analyzed by immunohistology using antibodies against the synaptonemal complex protein 3, (SCP3) and a mismatch repair protein1 (MLH1) located on the crossing over sites. The average number of cross overs per spermatocyte for the non-SCNT bulls were 45.04 ± 2.00, 39.17 ± 2.20, 42.04 ±2.54 (50 cells analysed per animal) and 46.63± 2.46 and 45.47±4.44 (per 20 cells analyzed) for SCNT bulls were similar, however, inter-individual variation was observed. A significantly higher (p<0.05) level of MLH1 expression in the cloned animals versus the normal animals was detected using a quantitative PCR approach. These results suggest meiotic recombination is not affected by the SCNT process but that the higher levels of MLH1 mRNA, in its role of DNA repair protein, could be a reflection of increased DNA damage within the SCNT animals. Further investigations are required to better elucidate the role of MLH1 in the cloned bulls. (Funded by the CRC program, AP was recipient of an OECD fellowship).