Isolation of subtelomeric DNA sequences labelling sheep and goat chromosome ends

Two techniques that make it possible to isolate telomere DNA are presented, using sheep as an example. The first technique is based upon the screening of a sheep BAC library with PCR amplified DNA segments preserved from high-power laser beam irradiation. Twenty-three BACs hybridising to 13 subtelomeric regions in sheep and goats were obtained (out of 27 in the sheep complement), of which 13 recognised more than one region, telomeric or not. Twenty-three microsatellites were isolated from these BACs and 22 were genetically mapped on the sheep international genetic map, always consistently with the cytogenetical localisation in 17 cases out of 22. These results are discussed. The second technique is based upon the selective cloning of subtelomeric enriched DNA. Preliminary results were obtained by this approach

Improvement of flow cytometry analysis and sorting of bull spermatozoa by optical monitoring of cell orientation as evaluated by DNA specific probing

International audienc

Improvement of flow cytometry analysis and sorting of bull spermatozoa by optical monitoring of cell orientation as evaluated by DNA specific probing

International audienc

Isolation of subtelomeric DNA sequences labelling sheep and goat chromosome ends

Two techniques that make it possible to isolate telomere DNA are presented, using sheep as an example. The first technique is based upon the screening of a sheep BAC library with PCR amplified DNA segments preserved from high-power laser beam irradiation. Twenty-three BACs hybridising to 13 subtelomeric regions in sheep and goats were obtained (out of 27 in the sheep complement), of which 13 recognised more than one region, telomeric or not. Twenty-three microsatellites were isolated from these BACs and 22 were genetically mapped on the sheep international genetic map, always consistently with the cytogenetical localisation in 17 cases out of 22. These results are discussed. The second technique is based upon the selective cloning of subtelomeric enriched DNA. Preliminary results were obtained by this approach.Isolement de séquences d'ADN subtélomériques chez les ruminants. Deux techniques permettant d'isoler l'ADN télomérique sont présentées, le mouton servant d'exemple. La première technique est basée sur le criblage d'une banque de BACs ovins avec des segments d'ADN amplifiés par PCR préservés de l'irradiation par un laser à forte puissance. Vingt trois BACs s'hybridant à 13 régions sub-télomériques (parmi les 27 du génome ovin) ont été obtenus, dont treize reconnaissent plus qu'une région unique, télomérique ou non. Vingt-trois microsatellites ont été isolés à partir des BACs et 22 cartographiés génétiquement sur la carte ovine internationale, de façon cohérente avec la localisation cytogénétique dans 17 cas sur 22. Ces résultats sont discutés. La seconde technique est basée sur le clonage sélectif d'ADN enrichi en régions sub-télomériques. Des résultats préliminaires ont été obtenus par cette approche