Boettcher P J, Freeman A E, Johnston S D, Smith R K, Beitz D C, McDaniel B T
Department of Animal Science, Iowa State University, Ames 50011, USA.
J Dairy Sci. 1996 Apr;79(4):647-54. doi: 10.3168/jds.S0022-0302(96)76410-X.
Two independent data files from the breeding herd of Iowa State University and six North Carolina herds were used to examine relationships between yield traits and mtDNA polymorphism. Maternal lineages were established by tracing ancestry of cows to founder females in the herd book of the Holstein Association. Data from Iowa State University were 1476 records from 602 cows from 29 maternal lineages. The nucleotides of mtDNA encoding rRNA were sequenced. Eleven sites of polymorphism were found. An animal model for gene substitution was used to examine the relationship between sequence differences and yield traits. Traits analyzed were mature equivalent yield of milk, fat, SNF, and milk energy as well as concentrations of fat, SNF, and milk energy. Effects of sequence differences were significant for most traits. Sequence information from the D-loop was available for 12 lineages from North Carolina. The effect of polymorphism at 4 sites was examined using 1472 records from 668 cows. Traits measured were the same, except that protein replaced SNF. No significant relationships existed between any of the traits and D-loop polymorphism, but results suggested that an association might exist between polymorphism and concentrations of milk yield, fat percentage, and energy. Whenever a significant relationship was detected, the effect of mutation (rare genotype) was detrimental.
来自爱荷华州立大学的繁殖牛群以及北卡罗来纳州六个牛群的两个独立数据文件被用于检验产量性状与线粒体DNA多态性之间的关系。通过追溯奶牛的谱系至荷斯坦协会畜群登记簿中的创始母牛来确定母系血统。爱荷华州立大学的数据来自29个母系的602头奶牛的1476条记录。对编码rRNA的线粒体DNA的核苷酸进行了测序。发现了11个多态性位点。使用基因替代动物模型来检验序列差异与产量性状之间的关系。分析的性状包括牛奶、脂肪、非脂乳固体和牛奶能量的成熟当量产量以及脂肪、非脂乳固体和牛奶能量的浓度。序列差异对大多数性状的影响显著。可获得来自北卡罗来纳州12个谱系的D环序列信息。使用来自668头奶牛的1472条记录检验了4个位点多态性的影响。测量的性状相同，只是用蛋白质替代了非脂乳固体。任何性状与D环多态性之间均不存在显著关系，但结果表明多态性与牛奶产量、脂肪百分比和能量浓度之间可能存在关联。每当检测到显著关系时，突变（稀有基因型）的影响都是有害的。
