tailieunhanh - Báo cáo sinh học: "rossbreeding effect on sexual dimorphism of body weight in intergeneric hybrids obtained between"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh Original cung cấp cho các bạn kiến thức về sinh học đề tài:Crossbreeding effect on sexual dimorphism of body weight in intergeneric hybrids obtained between . | Genet. Sei. Evol. 30 1998 163-170 @ Inra Elsevier Paris 163 Original article Crossbreeding effect on sexual dimorphism of body weight in inter generic hybrids obtained between Muscovy and Pekin duck Chein Taia Roger Rouvierb a Taiwan Livestock Research Institute Hsin-Hua Tainan 71210 Taiwan Republic of China b Station d amelioration génétique des animaux Centre de recherches de Toulouse Institut national de la recherche agronomique BP 27 31326 Castanet-Tolosan cedex France Received 8 December 1997 accepted 6 March 1998 Abstract - From a factorial crossbreeding experiment between two Muscovy and Pekin duck strains it appears that the increased body weight sexual dimorphism in favour of males in the Muscovy growing duck depends on the Muscovy mother in pure breds and in the reciprocal cross. The ratio of male to female body weight averages took the values of 1-84 and respectively at 4 10 16 20 30 and 40 weeks of age in the Muscovy progeny. This tendency was similar in the Pekin X Muscovy progeny. On the contrary this ratio took the values of and at 10 and 16 weeks of age in the Pekin progeny being similar in the Muscovy X Pekin progeny and respectively at 16 20 and 30 weeks of age . These results are evidence of a contribution of the Muscovy female duck to increase the body weight sexual dimorphism in duck by depressing the body weight growth in female progeny and not in the male progeny either in pure or crossbreeding. If the maternal effects are assumed to be similar in male and female progeny the ranking of the four genotypes in the female progeny could be explained by adding to the effect of sex-linked genes z chromosome the effect of genes on the w chromosome. Within a Mendelian inheritance pattern it may be suggested that besides the usual sex-linked gene effects coding genes of the non-pseudo-autosomal region NPAR of the Muscovy w chromosome depress growth when compared to the Pekin w chromosome. Inra Elsevier