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E N Signer

Publications and source records attributed to E N Signer.

11 recordsLinked to original sources

Are DNA profiles breed-specific? A pilot study in pigs.

In this study, DNA fingerprints from 32 unrelated domestic pigs were analysed and screened for breed-specificity. Three breed groups were analysed: Chinese Meishan, Large White and a collection of other European breeds. Ninety-three distinct and variable bands were used to estimate genetic distances between the animals. Between the groups these individual genetic distances substantially exceeded those within a group. Linear discriminant analysis showed that the 23 most common DNA fragments revealed sufficient breed-specificity as to assign each pig correctly to its breed or breed group. These findings, although based on a small sample, indicate that selective use of minisatellite variation in pigs appears to be a valuable novel approach toward the development of breed DNA profiles and the resolution of breed relationships.

Animals↗

DNA profiling reveals remarkably low genetic variability in a herd of SLA homozygous pigs.

Inbred strains of rodents have become indispensable for a wide range of biological studies. It has generally been accepted that genetic uniformity is unlikely to be achieved before 20 generations of brother x sister matings discouraging attempts to inbreed larger mammals. Nevertheless, pigs, homozygous for the swine MHC haplotype SLA b/b, have been inbred at the Babraham Institute for almost thirty years and used for immunological studies. Since the herd had not been studied at the DNA level, DNA profiling at multiple hypervariable loci was performed and surprisingly little genetic polymorphism and extremely high inter-individual resemblance were observed reminiscent of that observed in inbred strains of mice.

Animals↗

A panel of VNTR markers in pigs.

By cloning tandemly repeated sequences from the pig genome by use of non-porcine minisatellite probes for library screening, five novel polymorphic VNTR loci were isolated: three minisatellites and two satellite-like loci. Four of them could be mapped onto chromosomes by linkage analysis and/or in situ hybridization. They were assigned to Chromosomes (Chrs) 5, 6, 14, and 16. Physical mapping on both presumed satellites and on one of the minisatellites revealed that the former resided near or at the centromere and the latter towards the chromosome ends. The location of the minisatellite is of particular interest since, together with data on three other minisatellites previously isolated, it supports the idea that, as in humans, minisatellites may preferentially be subtelomeric also in pigs.

Alleles↗

DNA variability and parentage testing in captive Waldrapp ibises.

The Waldrapp ibis (Geronticus eremita) is one of the most endangered birds in the wild. The only real hope for its survival seems to rest with captive propagation, which has fortunately proved straightforward. Preservation of genetic diversity for maintaining viable populations is a major goal in any species conservation programme. Therefore sensitive tools have to be developed for the detection and regular monitoring of population variability. Individual identity has to be verified and each individual's pedigree defined in order to enable effective selective breeding. In this study, extensive DNA fingerprinting technology was applied to a group of 39 captive Waldrapp ibises. Five minisatellite probes were used. Despite the fact that the colony was founded by only six birds and that some of the founders were apparently related, highly polymorphic banding patterns were obtained. The human- and pig-derived probes MS1, MS31, p lambda g3 and pCMS12 each detected multiple distinct loci suitable for individual identification and resolution of parentage. Probe MS51 was locus-specific and revealed six different alleles. In addition, MS31 and p lambda g3 co-detected a band present in all females but none of the males and thus could be used for sex determination. For all but four individuals both parents could be identified unambiguously. The exceptions were offspring derived from a full sib mating in which DNA results allowed no distinction between the parents and the grandparents. Comparison of the parentage assigned by DNA analysis and by observation of breeding behaviour, respectively, showed agreement in all but five instances. Here, DNA data uncovered interchange of individuals in the stud book. Application of these minisatellite probes therefore offers an extremely sensitive means for individual identification and verification and completion of pedigree records.

Animals↗

Application of human minisatellite probes to the development of informative DNA fingerprints and the isolation of locus-specific markers in animals.

In this study, the alpha-globin 3' HVR (Jarman et al., 1986), the RNA transcripts of 33.15 and 33.6 (Carter et al., 1989), and the human locus-specific minisatellites MS1, MS8, MS31, MS32 (Wong et al., 1987), MS51, MS228A (Armour et al., 1989) and g3 (Wong et al., 1986) were applied to domestic pigs, common marmoset monkeys (Callithrix jacchus jacchus) and Waldrapp ibises (Geronticus eremita) and evaluated for their suitability firstly for isolating polymorphic VNTR markers from genomic libraries (pigs), and secondly for producing informative DNA fingerprints (pigs, marmosets and Waldrapp ibises).

Animals↗