Biomedical subjects

A Sertedaki

Publications and source records attributed to A Sertedaki.

4 recordsLinked to original sources

PubMed1996

CAC--the neglected repeat.

It is becoming increasingly clear that repetitive DNA is of biological significance as well as experimental importance. Here we review the information available about one type of repetitive DNA, the trinucleotide repeat (CAC)n, and briefly compare it with other trinucleotide repeats. Although much work has been done in analysing DNA fingerprinting patterns produced using the synthetic oligonucleotide (CAC)5 as a probe, there is relatively little information about individual (CAC)n-containing sequences and their abundance, organisation and distribution in mammalian DNA. From the data that is available, it is clear that there are at least two areas that should repay further study: (1) the organisation and generation of long sequences that contain (CAC)n motifs as part of a larger repeating unit (minisatellites) and (2) the distribution of small (CAC)n sequences (microsatellites), in particular their relationship to genes.

Base Sequence↗

PubMed1995

Oligonucleotide (CAC)5 fingerprinting: validity and reliability in paternity testing.

Following the development of DNA fingerprinting (Jeffreys et al., Nature 1985, 314, 67-73) using the minisatellite probes 33.15 and 33.6, many other fingerprinting probes have been described. The wide type M13 phage, 3' HVR region of alpha globin gene, F10 and various synthetic oligonucleotide probes have been shown to produce multiallelic and individual specific DNA fingerprints. The two probes developed by Jeffreys et al. have been extensively used in forensic and paternity determination in various laboratories, however, for the use of DNA fingerprints produced by synthetic oligonucleotide probes, still need critical evaluation. In this paper the statistical evaluations of the fingerprinting probes (CAC)5 was carried out by comparing the results produced by Jeffreys et al., using probes 33.15 and 33.6. The mutation rate calculated for (CAC)5 as 0.015 is nearly similar to the probe 33.15 (0.011) but higher than the probe 33.6 (0.005). The data obtained using (CAC)5 fingerprint in paternity cases from the northeast of England are presented.

DNA Fingerprinting↗

PubMed1992

Recombination between rhodopsin and locus D3S47 (C17) in rhodopsin retinitis pigmentosa families.

Autosomal dominant retinitis pigmentosa (adRP) has shown linkage to the chromosome 3q marker C17 (D3S47) in two large adRP pedigrees known as TCDM1 and adRP3. On the basis of this evidence the rhodopsin gene, which also maps to 3q, was screened for mutations which segregated with the disease in adRP patients, and several have now been identified. However, we report that, as yet, no rhodopsin mutation has been found in the families first linked to C17. Since no highly informative marker system is available in the rhodopsin gene, it has not been possible to measure the genetic distance between rhodopsin and D3S47 accurately. We now present a linkage analysis between D3S47 and the rhodopsin locus (RHO) in five proven rhodopsin-retinitis pigmentosa (rhodopsin-RP) families, using the causative mutations as highly informative polymorphic markers. The distance, between RHO and D3S47, obtained by this analysis is theta = .12, with a lod score of 4.5. This contrast with peak lod scores between D3S47 and adRP of 6.1 at theta = .05 and 16.5 at theta = 0 in families adRP3 and TCDM1, respectively. These data would be consistent with the hypothesis that TCDM1 and ADRP3 represent a second adRP locus on chromosome 3q, closer to D3S47 than is the rhodopsin locus. This result shows that care must be taken when interpreting adRP exclusion data generated with probe C17 and that it is probably not a suitable marker for predictive genetic testing in all chromosome 3q-linked adRP families.

Chromosome Mapping↗

PubMedDate not supplied

Study of three hypervariable DNA loci (D1S7; D7S22 and D12S11) in three European populations.

To investigate the population genetic characteristics and genetic affinity, DNA profiles of three highly polymorphic VNTR (variable number of tandem repeats) loci (D1S7; D7S22 and D12S11) were studied in 405 individuals from three major European populations (English, Spanish and Basques). Like other studies on VNTRs, a large significant heterozygote deficiency was observed in all three populations. This decrease was ascribed to the limitation, coalescence and non-detectibility of alleles associated with the RFLP (restriction fragment length polymorphism) technique, through which the VNTR loci are genotyped. When the non-detectable alleles were taken into consideration, analyses of fragment sizes at these loci within each sample, as well as their fixed binned analyses, reveal that the assumptions of independence of allelelic occurrences within and between loci are valid for this European data. By comparing genetic variation at three VNTR loci with 17 blood groups, proteins and HLA loci in three well defined European populations, it is shown that the pattern of differentiation at these sets of loci are in general parallel especially for the hypervariable loci HLA and VNTR. Fixed-bin allele frequencies, therefore, are the best descriptions of such a database both for population genetic and forensic calculation studies. The Basques, with regard to VNTR loci, do not show any reduced genetic variability compared to other two European populations (English and Spanish).

Chromosome Mapping↗