GENETIC CHARACTERIZATION OF THE HYPOTRICHOTIC MUTATION

描述：一种自发的少毛突变体，其特征是 身体大部分部分或完全没有毛发，是在 金博士的白化病实验室大鼠群体。初步数据显示 该性状暂时遗传为常染色体隐性基因 命名为修剪(Shn)，与任何其他已知的基因都不等位 大鼠的毛发缺失突变。Shn定位于大鼠染色体(Chr)10， 除RNU外，不包括任何其他已知的命名基因座 以影响被毛的形态。小鼠基因组的同源区域也缺乏 已知会导致隐性少毛的基因座。Shn突变 因此似乎确定了一种新的基因，这种基因对正常的 哺乳动物皮肤和毛发的发育或维持。要推进 了解shn基因在发育中的正常作用，金博士 建议从基因和基因两个方面描述shn突变。 典型的。在调查的基因水平上，他的目标是生产 Shn周围地区的精细结构遗传图谱。为了达到这个目标，他 将对杂合的Shn/+F1大鼠进行回交 可见的、生化的和可用于聚合酶链式反应的DNA标记的数量。分析 这个回交的大约250个后代将能够产生一个 高分辨率、高密度的区域遗传图谱，包括和 围绕着顺德。这一精细结构的遗传图谱，在推进 大鼠基因组20-30 cM区域的遗传特征，将 便于鉴定shn基因的探针和候选基因。 在表型水平上，他建议进行生化和 突变和非突变测交兄弟姐妹的组织学比较。 生化分析将集中在已知受控制的基因产品上。 通过与Shn相同区域的基因座定位。皮肤的组织学分析 而其他组织可能会显示出突变的多效性效应，并可能 有助于暗示特定的细胞类型、生物分子或特定时间 或参与突变表型发展的过程。这个 预计基因型别和表型调查将导致 对shn基因的鉴定，进而可能导致对其 在哺乳动物皮肤和毛发的正常发育中起着重要作用。

DESCRIPTION: A spontaneous hypotrichotic mutant, characterized by the partial or complete absence of hair over most of the body, was discovered in Dr. King's colony of albino laboratory rats. Preliminary data demonstrate that the trait is inherited as an autosomal recessive gene, provisionally named shorn (shn), that is not allelic with any of the other known hypotrichotic mutations in rats. Shn maps to rat Chromosome (Chr) 10, which, excepting rnu, does not include any other named loci that are known to affect coat morphology. Homologous regions of the mouse genome also lack loci that are known to cause recessive hypotrichosis. The shn mutation therefore appears to identify a new gene that is essential for the normal development or maintenance of mammalian skin and hair. To advance the understanding of the shn gene's normal role in development, Dr. King proposes to characterize the shn mutation both genotypically and phenotypically. At the genotypic level of investigation, he aims to produce a fine-structure genetic map of the region around shn. Toward this aim, he will conduct a backcross of shn/+ F1 rats that are heterozygous for a large number of visible, biochemical, and PCR-scorable DNA markers. Analysis of about 250 progeny from this backcross will allow generation of a high-resolution, high-density genetic map of the region including and surrounding shn. This fine-structure genetic map, while advancing the genetic characterization of a 20-30 cM region of the rat genome, will facilitate identification of probes and candidates for the shn gene. At the phenotypic level, he proposes to carry out biochemical and histological comparisons between mutant and non-mutant testcross siblings. The biochemical analysis will focus on gene products known to be controlled by loci mapping in the same region as shn. Histological analysis of skin and other tissues may reveal pleiotropic effects of the mutation, and could help to implicate particular cell types, biomolecules, or a particular time or process involved in the development of the mutant phenotype. The genotypic and phenotypic investigations are expected to result in the identification of the shn gene, which in turn could lead to studies on its role in the normal development of mammalian skin and hair.