Christensen V L, Havenstein G B, Ort D T, McMurtry J P, Nestor K E
Department of Poultry Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695, USA.
Poult Sci. 2007 Sep;86(9):1861-72. doi: 10.1093/ps/86.9.1861.
Inheritance of embryo thyroid function was measured in lines of turkeys. Two lines that had been selected for either increased egg production (E) or increased 16-wk BW (F) and their respective randombred controls (i.e., RBC1 and RBC2) were examined. Reciprocal crosses of dams and sires from each selected line and its randombred control were made to estimate sire line and dam line effects. Orthogonal contrasts were used to determine if the differences found were due to the presence of additive, nonadditive, or maternal, sex-linked, or both, gene effects. With the data involved, sex-linkage and maternal effects could not be separated. Embryo survival was measured for all lines and their reciprocal crosses. Crossing the RBC1 sire and E dam also resulted in better embryo survival and lower death losses at pipping than for the other cross- or purelines. Reciprocal crosses of the F and RBC2 lines showed better total embryo survival, and they survived pipping better than the F or RBC2 purelines. Thyroxine (T(4)) and triiodothyronine (T(3)) concentrations differed between the reciprocal crosses at external pipping, but the effects were inconsistent for the 2 data sets. Reciprocal tests indicated that maternal, sex-linked, or both, effects were present for T(3) concentrations at internal pipping in the E and RBC1 lines and at external pipping for the F and RBC2 lines. Reciprocal effects were significant for T(4) at internal pipping for both data sets. The RBC1 sire embryos had significantly higher T(3):T(4) ratios than the E line sire embryos at internal and external pipping, and the pureline RBC1 embryos had consistently higher ratios than the pureline E embryos. The differences for the T(3):T(4) ratios between these 2 lines at internal pipping, external pipping, and hatch appeared to be consistently additive in nature, although significant nonadditive or heterotic effects were present for the ratio at external pipping. Similar effects on the T(3):T(4) ratio were observed for the F and RBC2 lines at external pipping.
在火鸡品系中测定了胚胎甲状腺功能的遗传情况。对两个分别因产蛋量增加（E）或16周龄体重增加（F）而被选择的品系及其各自的随机交配对照（即RBC1和RBC2）进行了研究。对每个选择品系及其随机交配对照的母本和父本进行正反交，以估计父本品系和母本品系的效应。使用正交对比来确定所发现的差异是否归因于加性、非加性、或母体、性连锁或两者兼有的基因效应。根据所涉及的数据，无法区分性连锁效应和母体效应。对所有品系及其正反交组合测定了胚胎存活率。与其他杂交组合或纯系相比，RBC1父本与E母本的杂交也导致胚胎存活率更高，出雏时的死亡损失更低。F品系与RBC2品系的正反交组合显示出更好的总体胚胎存活率，且它们出雏时的存活情况优于F或RBC2纯系。在外部出雏时，正反交组合之间的甲状腺素（T(4)）和三碘甲状腺原氨酸（T(3)）浓度存在差异，但对这两个数据集而言，这些效应并不一致。正反交试验表明，在E和RBC1品系内部出雏时以及F和RBC2品系外部出雏时，T(3)浓度存在母体、性连锁或两者兼有的效应。对于两个数据集，在内部出雏时T(4)的正反交效应均显著。在内部和外部出雏时，RBC1父本的胚胎T(3):T(4)比值显著高于E品系父本的胚胎，并且纯系RBC1胚胎的比值始终高于纯系E胚胎。尽管在外部出雏时该比值存在显著的非加性或杂种优势效应，但这两个品系在内部出雏、外部出雏和出壳时T(3):T(4)比值的差异在本质上似乎始终是加性的。在外部出雏时，F和RBC2品系对T(3):T(4)比值也观察到类似的效应。
