系譜矩陣與數值模擬協助乳用公牛遺傳資源保存

黃鈺嘉 李世昌 林德育 廖仁寶 陳佳萱 張秀鑾

行政院農業委員會畜產試驗所

利用矩陣式系譜圖展示乳用公牛子代、孫代及曾孫代的冷凍精液保存頭數(k x 16，k個存有遺傳物質的後裔，含本身共15個祖先)，並藉助''公正''銅板的模擬及公牛的性染色體Y只能由父方而來的限制，從保有的特定重要公牛的''染色體數''估計保有遺傳物質百分率及標準偏差。若持有2頭子代精液可保有74.1±4.5%染色體，若保有8頭子代則可保有98.0±0.8%，但是保有源自相同子代的孫代，並無法增加保存的遺傳物質(源自同子的4頭孫代，僅可保有47.0±2.2%)，需要提高源自不同子代的孫代才能有效率的提高保存的遺傳物質。以現有保存的68頭源自多國的公牛冷凍精液，就2001年美國貢獻最大的20頭公牛遺傳資源保存進行模擬分析，發現標示顏色的系譜矩陣與保存特定遺傳資源的估算，可作為保種研究的協助工具。

關鍵語：矩陣式系譜圖、模擬、遺傳資源。

A MATRIX PEDIGREE ALONG WITH CHROMOSOME SEGREGATION SIMULATION FOR GENETIC RESOURCE CONSERVATION OF DAIRY CATTLE

Y. C. Huang, S. C. Lee, D. Y. Lin, R. B. Liaw, C. H. Cheng and H. L. Chang

Taiwan Livestock Research Institute, Council of Agriculture

A color edited pedigree matrix (k x 15, k offsprings with semen tanked and his 15 ancestors, including animal self) displays three generation genetic information for evaluation the desired genetic resources conserved. Mean and standard deviation of percentage of gene deposited from a particular sire was asymptotic estimated by sex-constrained chromosome segregation simulations through a serial of Bernoulli trails. Collection of semen from two and eight different sons can gather 74.1±4.5% and 98.0±0.8% chromosomes of the desired bull respectively. But, collection of semen from grandsons of the same son do not improve the conservation efficiency, four grandsons from the same son can only accumulate 47.0±2.2% chromosomes of the interested male ancestor. Semen from grandsons of different sons will be helpful to increase the percentage of the desired genomic material reserved when sons’ is not available. Analysis pedigrees of 68 bulls of a semen bank, the 20 most popular ancestors of USA top bulls in 2001were estimated as ideal genomic source individually. Results from pedigree matrices and simulations offer feasible directions in targeting favorite genetic resource.

Key words: Matrix pedigree, Simulation, Genetic resources.