Segregation of a major gene influencing ovulation in progeny of Lacaune meat sheep
Segregation of a major gene influencing ovulation in progeny of Lacaune meat sheep
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DOI：
10.1186/1297-9686-34-4-447
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发表时间：
2002-07-01
影响因子：
4.1
通讯作者：
Elsen, JM
中科院分区：
文献类型：
--
作者：
Bodin, L;SanCristobal, M;Elsen, JM
根据36只超高产母羊的自然产羔数和3个精选种母羊的子代资料，对拉考纳肉用母羊的排卵率(OR)遗传进行了研究。这些公熊是在人工智能中心根据其女儿产仔大小的平均值和变异性估计的繁殖值挑选出来的。非携带者拉考恩母羊受精后，产下121只F1子代和27只F1子代。12个儿子(每个父系4只)轮流用来给非携带者的拉考恩母羊授精，提供了公元前260只后代母羊。F1和BC后代来自私人农场，在第一和第二繁殖季节记录排卵率的实验农场断奶后收集。平均每只母羊有6.5条记录，超高产母羊的平均OR值很高(5.34)，其中38.4%的记录出现6条或更多的记录。F1代数据显示母羊内OR重复性高(r=0.54)，母羊间变异显著。每个家系的OR值都很高(大于或等于4)。分离分析提供了一个显著的似然比，并将这三个创始人归类为杂合子。BC母羊也表现出很高的OR重复性(r=0.47)，家系间的平均OR差异很大(从1.24到1.78)。在BC的12个家系中，有7个家系的母羊排卵量高(至少有一个大于或等于4的记录)，与经验检验分布相比，分离分析得出了非常显著的似然比。一小群BC母羊的平均排卵率表现出很高的变异性，其中一些母羊的排卵率非常高，证实了常染色体所携带的主基因和两个共显性等位基因的分离。纯合子非携带者母羊和杂合子母羊之间的差异约为观察尺度上的一个排卵量和潜在尺度上的2.2个标准偏差。
Inheritance of the ovulation rate (OR) in the Lacaune meat breed was studied through records from a small nucleus of 36 hyper-prolific ewes screened on farms on the basis of their natural litter size, and from progeny data of three selected Lacaune sires. These sires were chosen at the AI centre according to their breeding values estimated for the mean and the variability of their daughters' litter size. Non-carrier Lacaune dairy ewes were inseminated to produce 121 F1 daughters and 27 F1 sons. Twelve sons (four from each sire) were used in turn to inseminate non-carrier Lacaune dairy ewes providing 260 BC progeny ewes. F1 and BC progeny were brought from private farms and gathered after weaning on an experimental farm where ovulation rates were recorded in the first and second breeding seasons. With an average of 6.5 records each, the mean OR of hyper-prolific ewes was very high (5.34), and 38.4% of records showed a rate of 6 or more. F1 data showed high repeatability of OR (r = 0.54) within ewe, with significant variability among ewes. High OR (greater than or equal to 4) were observed in each family. A segregation analysis provided a significant likelihood ratio and classified the three founders as heterozygous. BC ewes also displayed high repeatability of OR (r = 0.47) and the mean OR varied considerably between families (from 1.24 to 1.78). Seven of the 12 BC families presented high-ovulating ewes (at least one record greater than or equal to 4) and segregation analysis yielded a highly significant likelihood ratio as compared to an empirical test distribution. The high variability of the mean ovulation rate shown by a small group of daughters of BC ewes inseminated by putative carrier F1 rams, and the very high ovulation rate observed for some of these ewe lambs, confirmed the segregation of a major gene with two co-dominant alleles borne by an autosome. The difference between homozygous non-carriers and heterozygous ewes was about one ovulation on the observed scale and 2.2 standard deviations on the underlying scale.