RESUMO
Corpus callosum (CC) size is a complex trait, characterized by a gradation of values within a normal range, as well as abnormalities that include a small or totally absent CC. Among inbred mouse strains with defects of the CC, BTBR T(+)tf/J (BTBR) mice have the most extreme phenotype; all animals show total absence of the CC and severe reduction of the hippocampal commissure (HC). In contrast, the BALB/cByJ (BALB) strain has a low frequency of small CC and consistently normal HC. Reciprocal F(1) crosses between BTBR and BALB suggest the presence of X-linked quantitative trait loci (QTLs) affecting CC size. Through linkage analysis of backcross male progeny, we have localized two regions on the X chromosome, having peaks at 68.5 Mb (approximately 29.5 cM) and at 134.5 Mb (approximately 60.5 cM) that are largely responsible for the reciprocal differences, with the BTBR allele showing X-linked dominant inheritance associated with CC defects.
Assuntos
Corpo Caloso/anatomia & histologia , Genes Ligados ao Cromossomo X/genética , Organogênese/genética , Locos de Características Quantitativas/genética , Agenesia do Corpo Caloso , Análise de Variância , Animais , Mapeamento Cromossômico , Anormalidades Congênitas/genética , Corpo Caloso/embriologia , Ligação Genética , Hipocampo/anormalidades , Hipocampo/anatomia & histologia , Hipocampo/embriologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Mutantes Neurológicos , Tamanho do Órgão , Especificidade da Espécie , Cromossomo X/genéticaRESUMO
By use of chlorambucil, we have generated a mouse mutation called scraggly (sgl) that exhibits skin and hair defects. Homozygous mutant mice exhibit hair loss, skin defects, and abnormalities in sebaceous lipid composition. We have constructed a high-resolution genetic map of mouse Chromosome (Chr) 19 that links this mutation to the anonymous DNA marker D19Umi1. An additional cross, (BALB/c x CAST/Ei) F(1) x BALB/c, was used to map markers around this mutation as well as to map the potential candidate genes, Fgf8 and Cyp17. Allelism tests between sgl and asebia (ab), another hair loss mutation on mouse Chr 19, showed that these genes were separate and distinct.
Assuntos
Cabelo/anormalidades , Mutação , Proteínas , Animais , Sequência de Bases , Clorambucila/toxicidade , Mapeamento Cromossômico , Cruzamentos Genéticos , Primers do DNA/genética , Feminino , Cabelo/metabolismo , Homozigoto , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Mutagênicos/toxicidade , Fenótipo , Glândulas Sebáceas/anormalidades , Glândulas Sebáceas/metabolismo , Anormalidades da Pele/genética , Anormalidades da Pele/metabolismo , Proteínas WntRESUMO
Ornithine aminotransferase (OAT), a mitochondrial matrix enzyme, is deficient in patients with gyrate atrophy of the choroid and retina. In human, the OAT structural gene maps to Chromosome (Chr) 10q26 and several OAT-related sequences, some of which are known to be processed pseudogenes, which map to Xp11.3-11.21. Here, we report chromosomal localization in the mouse of the OAT gene and related sequences. Genomic DNA blot analysis of a well-characterized panel of Chinese hamster x mouse somatic cell hybrids using a human OAT probe revealed two murine loci, one on mouse Chr 7 and the other on Chr X. In addition, segregation of restriction fragment length polymorphisms (RFLPs) detected by the OAT probe in recombinant inbred (RI) strains detected a third locus on Chr 3 and positioned the X locus near Cf-8 and Rsvp. Progeny of an intersubspecific backcross were used to map the Chr 7 locus between Tyr and Int-2, near Cyp2e-1.