RESUMO
Haplotype analysis was performed in 35 autosomal dominant polycystic kidney disease (ADPKD) families typed with 13 markers close to the PKD1 locus. The identification of recombinants close to the PKD1 gene on chromosome 16p indicates that PKD1 lies between CMM65 distally and 26-6 proximally. In addition, three unlinked (PKD2) families and two families with potential new mutation were identified.
Assuntos
Haplótipos/genética , Rim Policístico Autossômico Dominante/genética , Adulto , Idoso , Cromossomos Humanos Par 16 , Feminino , Ligação Genética , Marcadores Genéticos , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Proteínas/genética , Canais de Cátion TRPPRESUMO
A genetic heterogeneity analysis of 35 kindreds with adult-onset polycystic kidney disease (ADPKD) was carried out using the D16S85, D16S84, D16S125 and D16S94 loci that are closely linked to the PKD1 locus on chromosome 16. The results show that the likelihood of two ADPKD loci is 2,514.9 times greater than for a single locus (P < 0.0001). The maximum likelihood lod score is 27.38 under heterogeneity with PKD1 lying 4.9 cM proximal to D16S85 (in males). At least 3% of kindreds are unlinked to PKD1, since the 95% confidence limits of alpha, the proportion of families linked to PKD1, are 0.54-0.97. Only 2 out of 35 kindreds (5.7%) show statistically significant evidence of non-linkage to PKD1, with conditional probabilities of 0.987 and 0.993 that the disease locus is unlinked. This confirms the existence of a small subgroup of ADPKD kindreds that are unlinked to PKD1 and provides a firm basis for genetic counselling of this population on the basis of DNA probes.
Assuntos
Cromossomos Humanos Par 16 , Ligação Genética , Rim Policístico Autossômico Dominante/genética , Adulto , Distribuição de Qui-Quadrado , Feminino , Testes Genéticos , Variação Genética , Genótipo , Humanos , Funções Verossimilhança , Masculino , Rim Policístico Autossômico Dominante/diagnósticoRESUMO
Analysis of genetic linkage data in 33 adult onset polycystic kidney (ADPKD) families was carried out using probes for the D16S85, D16S84, and D16S94 loci. The data set of 33 families shows no evidence of genetic heterogeneity since one unlinked family was previously excluded. Two point linkage analysis showed maximum likelihood values of the recombination fraction of 0.07 for ADPKD and D16S85 (lod score 18.78), 0.02 for ADPKD and D16S84 (lod score 7.55), and 0.00 for ADPKD and D16S94 (lod score 6.73). Multipoint analysis showed a maximum likelihood order of tel-D16S85-0.06-D16S84-0.02-(PKD1, D16S94)-cen with a multipoint lod score of 32.16. Analysis of rare recombinants lying close to PKD1 gave results consistent with this order.
Assuntos
Cromossomos Humanos Par 16 , Rim Policístico Autossômico Dominante/genética , Mapeamento Cromossômico , Marcadores Genéticos , Humanos , Escore LodRESUMO
In Drosophila melanogaster, the P-M and I-R systems of hybrid dysgenesis are associated with high rates of transposition of P and I elements, respectively, in the germlines of dysgenic hybrids formed by crossing females of strains without active elements to males of strains containing them. Transposition rates are not markedly accelerated in the reciprocal, nondysgenic hybrids. Previous attempts to evaluate the extent to which hybrid dysgenesis-mediated P transposition contributes to mutational variance for quantitative characters by comparing the responses to selection of P-M dysgenic and nondysgenic hybrids have given variable results. This experimental design has been extended to include an additional quantitative trait and the I-R hybrid dysgenesis system. The selection responses of lines founded from both dysgenic and nondysgenic crosses showed features that would be expected from the increase in frequency of initially rare genes with major effects on the selected traits. These results differ from those of previous experiments which showed additional selection response only in lines started from dysgenic crosses, and can be explained by the occasional occurrence of large effect transposable element-induced polygenic mutations in both dysgenic and nondysgenic selection lines. High rates of transposition in populations founded from nondysgenic crosses may account for the apparently contradictory results of the earlier selection experiments, and an explanation is proposed for its occurrence.
