tailieunhanh - báo cáo khoa học: "Note Selection for increased and decreased total number of young born in the first three parities in mice"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Note Selection for increased and decreased total number of young born in the first three parities in mice | Génét. Sél. Evol. 1988 20 2 259-266 Note Selection for increased and decreased total number of young born in the first three parities in mice Yolanda BAYON . FUENTE and F. SAN PRIMITIVO Departamento de Production Animal Universidad de León León Spain Summary A selection experiment carried out in mice for increased L and decreased L total number of young born alive in the first three parities TNY-3 had been started in our laboratory. Data from the first 8 generations reported by Fuente San Primitivo 1985 showed considerable responses for upward and downward selection. In the present article results obtained for generations 9-13 are described. Realized heritability in the L line showed a gradual decline through generations the value obtained for generations 9-13 being considerably lower than that estimated in the first 8 generations by Fuente San Primitivo 1985 . No response was detected in the L line in this second period and a reversion towards the control line mean C occuưed. After 13 generations of selection cumulated response measured as a deviation from the control line was young in L and - young in L . Means for 1st 2nd and 3rd litter size in generation 13 were and young in L and young in c and and young in zr respectively. Means for 6week body weight in generation 13 were g g and g in L c and L respectively. Key words mice litter size selection. Resume Selection divergente sur le nombre total de Jeunes nés dans les trois premieres portées chez la souris Une experience de selection a été conduite sur des souris dans notre laboratoire afin d augmenter dans la lignée L et de diminuer dans la lignée L le nombre total de jeunes nés vivants dans les trois premieres portées TNY-3 . Les observations faites sur les huit premières generations décrites par Fuente San Primitivo 1985 mettaient en evidence d importantes réponses à la sélection dans les deux lignées. L .