Chromosome-specific subfamilies within human alphoid repetitive DNA

Detection of chromosome aberrations in the human interphase nucleus by visualization of specific target DNAs with radioactive and non-radioactive in situ hybridization techniques: diagnosis of trisomy 18 with probe L1.84

“…Evidence is accumulating that the sequence heterogeneity within this family is distributed in a chromosome specific manner, so that each individual chromosome may be characterized by the presence of its own distinct alphoid DNA subfamily (Wolfe et al 1985;JCrgensen et al 1986). Alphoid subfamilies may display a characteristic restriction-site spacing, which would allow their detection in Southern blot experiments (Willard 1985;JCrgensen 1986;Devilee et al 1986b). Clone L1.84 represents such a subfamily on chromosome 18.…”

PCR-generated padlock probes distinguish homologous chromosomes through quantitative fluorescence analysis

“…The binding solution was removed and the beads were washed three times with washing buffer before adding 50 ml of 0.15 M LiOH. After 5 min, the denaturing solution with the single-stranded padlock probes was removed to a clean test tube and neutralized with 50 ml of 0.15 M NH 4 Cl. The released padlock probes were precipitated with 3 mg of glycogen (Roche, Basel, Switzerland) added as carrier, resuspended in 25 ml TE-buffer, and quantitated by spectrophotometry.…”

“…These subfamilies differ in the number of monomer units within each higher-order repeat and in monomer sequence. 2,4 Analysis of alpha satellite DNA arrays from several homologous chromosomes has revealed polymorphisms both within and between individual centromeres, both with respect to the number of higher-order repeats and their sequence composition. 5 -7 Chromosomal heteromorphisms have been used to distinguish homologous chromosomes, and they were used to map the first gene to a human autosome -the Duffy blood group locus to chromosome 1.…”

Ultraviolet light-induced cleavage of DNA in presence of iodoHoechst 33258: the sequence specificity of the reaction

“…The columns of four numbers show the incidence of each of the G,T,A, and C, in the respective positions in the consensus sequence, amongst the twenty-nine strong and very strong sites. The effect of base substitutions on the UV/iodoHoechst 33258 cleavage reaction The natural microheterogeneity of alpha-DNA allows the cloning of 340bp alpha-DNA sequences containing a small number of base substitutions (17,18). Relative to alpha-32, clone alpha-82 has 12 and alpha-22 has 25 base substitutions in the 185 bp region that was analyzed (see Figure 4).…”

“…By use of a sequencing primer, the sequence selectivity of a DNA damaging agent can be examined for any DNA sequence cloned into the polylinker site of M13 vectors. The natural sequence microheterogeneity in the 340bp (base pair) repeat sequence in human alpha-DNA was exploited to generate clones with random base substitutions (17,18). Three 340 bp alpha-DNA clones were employed to examine the effect of base substitutions on the UV/iodoHoechst 33258 cleavage reaction.…”