Exon skipping in the KIT gene causes a Sabino spotting pattern in horses
Exon skipping in the KIT gene causes a Sabino spotting pattern in horses
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DOI：
10.1007/s00335-005-2472-y
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发表时间：
2005-11-01
期刊：
影响因子：
2.5
通讯作者：
Bailey, E
中科院分区：
文献类型：
--
作者：
Brooks, SA;Bailey, E
特征为面部、小腿或腹部有白色斑点，腹部有散布的白色毛发。基于人和猪的可比表型，研究了KIT基因作为Sabino表型的起源。在这篇文章中，我们报告了一种类型的萨比诺斑点模式的遗传基础，我们称之为萨比诺1，与符号SB 1和sb 1代表的等位基因。通过逆转录聚合酶链反应（RT-PCR）和测序基因型SB 1/SB 1，SB 1/sb 1和sb 1/sb 1的马的cDNA的KIT的转录本进行了表征。具有Sabino I性状的马产生了不具有外显子17的KIT剪接变体。KIT基因组DNA测序显示，在内含子16，外显子16后的1037个碱基的T与A的碱基取代引起的单核苷酸多态性（SNP）。与SB 1相关的SNP被命名为KI 16 + 1037 A。这种取代消除了MnlI限制性位点，并允许使用PCR-RFLP来表征这种碱基变化的个体。在田纳西州走马家族中观察到该SNP与Sabino 1之间的完全连锁（对于θ = 0，LOD = 9.02）。还对其他品种的个体马进行了测试。该SNP的所有5匹纯合马均为白色，并且具有该SNP的一个拷贝的所有68匹马均表现出Sabino I表型或为多模式。由于白色斑点图案的加性效应，一些多图案个体出现白色。然而，13匹具有其他Sabino型模式的马没有这种SNP。基于这些结果，我们提出以下结论：（1）在内含子16中发现的这种SNP负责外显子17的跳跃和SB 1表型，（2）白色和Sabino表型是异质的，并且这种机制不是产生描述为“Sabino”或“白色”模式的唯一方式，以及（3）SB 1的纯合性导致完全或几乎完全的白色表型。
characterized by white patches on the face, lower legs, or belly, and interspersed white hairs on the midsection. Based on comparable phenotypes in humans and pigs, the KIT gene was investigated as the origin of the Sabino phenotype. In this article we report the genetic basis of one type of Sabino spotting pattern in horses that we call Sabino 1, with the alleles represented by the symbols SB1 and sb1. Transcripts of KIT were characterized by reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing cDNA from horses with the genotypes SB1/SB1, SB1/sb1, and sb1/sb1. Horses with the Sabino I trait produced a splice variant of KIT that did not possess exon 17. Genomic DNA sequencing of KIT revealed a single nucleotide polymorphism (SNP) caused by a base substitution for T with A in intron 16, 1037 bases following exon 16. The SNP associated with SB1 was designated KI16+1037A. This substitution eliminated a MnlI restriction site and allowed the use of PCR-RFLP to characterize individuals for this base change. Complete linkage was observed between this SNP and Sabino 1 in the Tennessee Walking Horse families (LOD = 9.02 for Theta = 0). Individual horses from other breeds were also tested. All five horses homozygous for this SNP were white, and all 68 horses with one copy of this SNP either exhibited the Sabino I phenotype or were multipatterned. Some multipatterned individuals appeared white due to the additive effect of white spotting patterns. However, 13 horses with other Sabino-type patterns did not have this SNP. Based on these results we propose the following: (1) this SNP, found within intron 16, is responsible for skipping of exon 17 and the SB1 phenotype, (2) the White and Sabino phenotypes are heterogeneous and this mechanism is not the only way to produce the pattern described as "Sabino" or "White," and (3) homozygosity for SB1 results in a complete or nearly completely white phenotype.