Marklund S, Kijas J, Rodriguez-Martinez H, Rönnstrand L, Funa K, Moller M, Lange D, Edfors-Lilja I, Andersson L
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala Biomedical Centre, S-75124 Uppsala, Sweden.
Genome Res. 1998 Aug;8(8):826-33. doi: 10.1101/gr.8.8.826.
The change of phenotypic traits in domestic animals and crops as a response to selective breeding mimics the much slower evolutionary change in natural populations. Here, we describe that the dominant white phenotype in domestic pigs is caused by two mutations in the KIT gene encoding the mast/stem cell growth factor receptor (MGF), one gene duplication associated with a partially dominant phenotype and a splice mutation in one of the copies leading to the fully dominant allele. The splice mutation is a G to A substitution in the first nucleotide of intron 17 and leads to skipping of exon 17. The duplication is most likely a regulatory mutation affecting KIT expression, whereas the splice mutation is expected to cause a receptor with impaired or absent tyrosine kinase activity. Immunocytochemistry showed that this variant form is expressed in 17- to 19-day-old pig embryos. Hundreds of millions of white pigs around the world are assumed to be heterozygous or homozygous for the two mutations. [The EMBL accession numbers for porcine KIT10101, KIT10202, KIT20202, and KIT20101 are AJ223228-AJ223231, respectively.]
家畜和农作物的表型性状变化作为对选择性育种的反应，类似于自然种群中慢得多的进化变化。在此，我们描述了家猪中的显性白色表型是由编码肥大/干细胞生长因子受体（MGF）的KIT基因中的两个突变引起的，一个基因重复与部分显性表型相关，另一个拷贝中的剪接突变导致完全显性等位基因。剪接突变是内含子17第一个核苷酸中的G到A替换，导致外显子17跳跃。该重复很可能是影响KIT表达的调控突变，而剪接突变预计会导致酪氨酸激酶活性受损或缺失的受体。免疫细胞化学显示这种变异形式在17至19日龄的猪胚胎中表达。全世界数亿头白猪被认为对于这两个突变是杂合或纯合的。[猪KIT10101、KIT10202、KIT20202和KIT20101的EMBL登录号分别为AJ223228 - AJ223231。]
