Bovine MHC class II restriction fragment length polymorphism linked to expressed polymorphism

Offprint requests to: I. Joosten.     

An additional restriction fragment length polymorphism at the thyroglobulin gene.

The study was aimed at the screening of human chromosomal DNA for restriction fragment length polymorphism (RFLP) at the human thyroglobulin (hTg) gene locus. The RFLP screening was performed in a typical way. As hybridization probes were used 5 Pst I fragments of hTg cDNA of the total length 5.1 kb pairs cloned in pBR 322. One not described polymorphism was found by using the probe hTg 10, (nucleotides from position 4830 to 5810 in the 3' flanking region of hTg). Restriction enzyme Msp I identified a single two allele polymorphism: A1: 3.5 kb and A2: 2.5 kb. Of 32 unrelated healthy individuals two were homozygous for 3.5 kb, one was homozygous 2.5 kb and 29 were heterozygous for both 3.5 kb. and 2.5 kb. Thus, the frequencies of the 3.5 and 2.5 kb Msp I alleles were 0.52 and 0.48 respectively.     

X-linked immunodeficiency with hyperimmunoglobulinemia M appears to be linked to the DXS42 restriction fragment length polymorphism locus

Summary The gene involved in X-linked immunodeficiency with hyperimmunoglobulinemia M (XHM) was localized by the use of nine restriction fragment length polymorphic (RFLP) markers covering the entire X chromosome. Multipoint linkage analysis of RFLP data obtained in a three generation XHM pedigree indicates the Xq24-q27 area around the DXS42 RFLP locus as the most likely localization of the XHM locus.     

An integrated restriction fragment length polymorphism--amplified fragment length polymorphism linkage map for cultivated sunflower.

Restriction fragment length polymorphism (RFLP) maps have been constructed for cultivated sunflower (Helianthus annuus L.) using three independent sets of RFLP probes. The aim of this research was to integrate RFLP markers from two sets with RFLP markers for resistance gene candidate (RGC) and amplified fragment length polymorphism (AFLP) markers. Genomic DNA samples of HA370 and HA372, the parents of the F2 population used to build the map, were screened for AFLPs using 42 primer combinations and RFLPs using 136 cDNA probes (RFLP analyses were performed on DNA digested with EcoRI, HindIII, EcoRV, or DraI). The AFLP primers produced 446 polymorphic and 1101 monomorphic bands between HA370 and HA372. The integrated map was built by genotyping 296 AFLP and 104 RFLP markers on 180 HA370 x HA372 F2 progeny (the AFLP marker assays were performed using 18 primer combinations). The HA370 x HA372 map comprised 17 linkage groups, presumably corresponding to the 17 haploid chromosomes of sunflower, had a mean density of 3.3 cM, and was 1326 cM long. Six RGC RFLP loci were polymorphic and mapped to three linkage groups (LG8, LG13, and LG15). AFLP markers were densely clustered on several linkage groups, and presumably reside in centromeric regions where recombination is reduced and the ratio of genetic to physical distance is low. Strategies for targeting markers to euchromatic DNA need to be tested in sunflower. The HA370 x HA372 map integrated 14 of 17 linkage groups from two independent RFLP maps. Three linkage groups were devoid of RFLP markers from one of the two maps.     

Dinucleotide polymorphism at the DXS1178 locus is tightly linked to PGK1 at Xq13

A polymorphic CA repeat (locus name DXS1178) was isolated from a 1-megabase YAC (OTCC) containing the OTC gene, located at Xp21.1. However, amplification in human-rodent hybrid cells and segregation analysis in three CEPH families mapped the DXS1178 locus at Xq13. The mapping ambiguity is apparently caused by the chimeric nature of the OTCC YAC clone.     

Use of restriction fragment length polymorphism to fingerprint beets at the genotype and species levels

Summary cDNA probes have been used to assess genetic variation in beet using hybridisation techniques that detect restriction fragment length polymorphism. Probes have been identified which differ in the levels of variation that they can detect (i) within closely related genetic material of sugar beet, and (ii) between sugar beet and a taxonomically distant Beta species.     

Identification of amplified restriction fragment length polymorphism markers linked to genes controlling boar sperm viability following cryopreservation

This study investigated two hypotheses: 1) that consistent between-boar variation in frozen semen quality exists and is genetically determined, and 2) molecular markers linked to genes controlling semen freezability can be identified using amplified restriction fragment length polymorphism (AFLP) technology. Five ejaculates were collected from each of 129 boars. Semen was diluted into a commercial freezing buffer (700 mOsm/kg, 3% glycerol) and five straws (0.5 ml) per ejaculate were cryopreserved (to -5 degrees C at 6 degrees C/min, then -5 degrees C to -80 degrees C at 40 degrees C/min). Semen was assessed for percentage of motile cells, motility characteristics (computer-aided semen analysis; CASA), plasma membrane integrity (SYBR-14 positive), and acrosome integrity (positive for fluorescein-labeled peanut agglutinin; PNA). Consistent between-boar variability was detected for postthaw sperm motility (P < 0.01), membrane integrity (P < 0.01), acrosome integrity (P < 0.01), and all CASA characteristics (P < 0.05). There was no significant difference between ejaculates (P > 0.05) or straws (P > 0.05) for any viability assessment. Multivariate pattern analysis of the viability data set highlighted three groups of boars producing spermatozoa with poor, average, and good postthaw recovery (42, 63, and 24 boars, respectively). DNA from Large White boars (n = 22) previously classified as good and poor freezers was screened for AFLP markers. Twenty-eight polymerase chain reaction primer combinations generated 2182 restriction fragment bands, of which 421 were polymorphic. Sixteen candidate genetic markers (P < 0.005) were identified by comparing the AFLP profile with semen freezability using logistic regression analysis. These findings support the hypothesis that there is a genetic basis for variation in postthaw semen quality between individuals, and that AFLP technology may be able to identify molecular markers linked to genes influencing this variation.     

An NcoI restriction fragment length polymorphism at the human steroid sulphatase gene locus

Summary The DNA diagnosis of X-linked recessive ichthyosis vulgaris (incidence: approx. 1 in 5000 males) can be complicated by the absence of restriction fragment length polymorphisms (RFLPs) in the STS (steroid sulphatase) gene. An RFLP sequence in NcoI-digested genomic DNA is reported, which it is hoped may prove helpful in diagnosis.