RESUMO
Comparative mapping between the rat and mouse genomes has shown that some chromosomes are entirely or almost entirely conserved with respect to gene content. Such is the case of rat chromosome 11 (RNO11) and mouse chromosome 16 (MMU16). We determined to what extent such an extensive conservation of synteny is associated with a conserved gene order. Therefore, we regionally localized several genes on RNO11. The comparison of the gene map of RNO11 and MMU16 unambiguously shows that the gene order has not been conserved in the Murinae lineage, thereby implying the occurrence of intrachromosomal evolutionary rearrangements. The transition from one chromosome configuration to the other one can be explained either by two intrachromosomal recombinations or by a single intrachromosomal recombination accompanied by neocentromere emergence.
Assuntos
Cromossomos de Mamíferos/genética , Sequência Conservada/genética , Evolução Molecular , Ordem dos Genes/genética , Rearranjo Gênico/genética , Sintenia/genética , Animais , Mapeamento Cromossômico/métodos , Genoma , Camundongos , RatosRESUMO
The rat gene encoding the microphthalmia-associated transcription factor (Mitf) was assigned to rat Chromosome (Chr) 4q34-q41, as well as the Gata2 and Mem1 genes. Rat Chr 4 is homologous to mouse Chr 6 and human Chr 3, which carry the Mitf (MITF) gene in these species (MMU 6, 40.0 cM, and HSA 3p14.1-p12.3). mib/mib rats, which are characterized by depigmentation, microphtalmy, osteopetrosis, and neurological disorders were shown to bear a deletion covering several kilobases of genomic DNA in the Mitf gene and to lack Mitf mRNA. The Mitf mutation in the mib/mib rats is thus very likely to be a Mitf null mutation, causing a phenotype similar to the one observed in the miVGA-9 mice, but including osteopetrosis as an additional feature.
Assuntos
Mapeamento Cromossômico , Proteínas de Ligação a DNA/genética , Microftalmia/genética , Fatores de Transcrição/genética , Animais , Cromossomos Humanos Par 3 , Proteínas de Ligação a DNA/biossíntese , Marcadores Genéticos , Humanos , Células Híbridas , Camundongos , Fator de Transcrição Associado à Microftalmia , Reação em Cadeia da Polimerase , Ratos , Ratos MutantesRESUMO
Seven genes were regionally localized on rat Chromosome (Chr) 1, from 1p11 to 1q42, and two of these genes were also included in a linkage map. This mapping work integrates the genetic linkage map and the cytogenetic map, and allows us to orient the linkage map with respect to the centromere, and to deduce the approximate position of the centromere in the linkage map. These mapping data also indicate that the Slc9a3 gene, encoding the Na+/H+ exchanger 3, is an unlikely candidate for the blood pressure loci assigned to rat Chr 1. These new localizations expand comparative mapping between rat Chr 1 and mouse or human chromosomes.
