Assignment of rat linkage group V to chromosome 19 by single-strand conformation polymorphism analysis of somatic cell hybrids

Single nucleotide polymorphism in growth hormone gene exon-4 and exon-5 using PCR-SSCP in Black Bengal goats - A prolific meat breed of India

Single-strand conformation polymorphism (SSCP) showed 7 and 5 haplotypes in caprine GH gene exon-4 and exon-5 in Black Bengal, a prolific meat breed from India. All haplotypes revealed novel sequences. In exon-4 codons 6, 36 and 54 were polymorphic. At codon 6, AA arginine (R) changed to histidine (H) and proline (P), showing 6RR, 6HH and 6PP genotypes. At codons 36 three genotypes DD, VV and DV were observed due to SNP showing changed from aspartic acid (D) to valine (V). At codon 54, AA change from arginine to tryptophan (W) and 54RR and 54WW genotypes were observed. SNPs were also observed at codon 23 (serine to threonine) and at 37 (arginine to proline) in 8% of goats. In exon-5 nucleotide substitution (G/A) at codon 10 and (A/G) at 14 respectively changed AA from glycine (K) to glutamic acid (E). Silent mutations were also observed.

Polymorphisms at the five exons of the growth hormone gene in the algarvia goat: possible association with milk traits

The present preliminary study attempts to establish associations between milk production traits and genetic polymorphisms at the GH gene in the Algarvia goat. The DNA of 108 goats of the indigenous Portuguese Algarvia breed was evaluated. Single-strand conformation polymorphisms (SSCP) were identified at the five exons of the goat growth hormone (gGH) gene. Two conformational patterns were found in each of exons 1 and 2, four in exon 3, six in exon 4 and five in exon 5. An association between these SSCP patterns with milk, fat and protein production, and fat and protein content was examined. Patterns F/F of exon 4 and A/A of exon 5 were positively associated with milk production (P<0.05). The results demonstrated that the gGH gene could be exploited as a candidate gene for marker-assisted selection in goat breeds.

Host genes controlling the susceptibility and resistance to squamous cell carcinoma of the tongue in a rat model

Development of tongue carcinoma (TC) in rats by 4-nitroquinoline 1-oxide (4NQO), a potent carcinogen, is under host genetic control. The inbred Dark-Agouti (DA) strain rats showed a much higher susceptibility to TC than the Wistar-Furth (WF) strain. The author's previous study on crosses between two strains postulated a susceptibility gene in DA and a resistance gene in WF rats. This hypothesis was confirmed by the genetic analysis of the backcrosses to either parent and F2 with a simple sequence repeat polymorphism analysis. In the crosses between the DA and WF strains of rats, two major independently segregating host loci that influenced the cancer development by application of 4NQO positively or negatively were identified and mapped. DA rats had a semidominant susceptibility gene, Stc1, closely linked with D19Mit9 on chromosome 19, which was on the segment syntenic to human chromosome 16. In contrast, WF rats had a semidominant resistance gene, Rtc1, closely linked with D1Rat320 on chromosome 1, which is syntenic to human chromosome 11. The presence of other susceptibility and resistance genes on some chromosomes of both DA and WF rats was suspected, and they will be clarified in the near future. These findings provide powerful evidence that chemically induced tongue carcinogenesis is a multigenetic event.

The LEXF: a new set of rat recombinant inbred strains between LE/Stm and F344

A new set of rat RI strains consisting of 11 independent strains and 13 of their substrains was established by inbreeding F2 rats between F344/DuCrj and LE/Stm. The strain distribution pattern was examined for 66 microsatellite loci, 8 biochemical genetic markers, 2 histocompatibility loci, and 2 coat color genes. A rat salivary protein gene Spe1 was newly mapped on Chr 1.

A genetic linkage map of the rat derived from recombinant inbred strains

We have constructed a genetic linkage map in the rat by analyzing the strain distribution patterns of 500 genetic markers in a large set of recombinant inbred strains derived from the spontaneously hypertensive rat and the Brown-Norway rat (HXB and BXH recombinant inbred strains). 454 of the markers could be assigned to specific chromosomes, and the amount of genome covered by the mapped markers was estimated to be 1151 centimorgans. By including a variety of morphologic, biochemical, immunogenetic, and molecular markers, the current map integrates and extends existing linkage data and should facilitate rat gene mapping and genetic studies of hypertension and other complex phenotypes of interest in the HXB and BXH recombinant inbred strains.

Assignment of rat Jun family genes to chromosome 19 (Junb), chromosome 5q31-33 (Jun), and chromosome 16 (Jund)

By means of somatic cell hybrids segregating rat chromosomes, we determined the chromosome localization of three rat genes of the Jun family: Junb (Chr 19), Jun (=c-Jun) (Chr 5) and Jund (Chr 16). The Jun gene was also localized to the 5q31-33 region by fluorescence in situ hybridization. These rat gene assignments reveal two new homologies with mouse and human chromosomes, and provide a new example of synteny conserved in the human and a rodent species (the mouse), but split between the two rodent species.

Linkage of 11 beta-hydroxylase mutations with altered steroid biosynthesis and blood pressure in the Dahl rat

In Dahl salt-hypertension sensitive (S) and resistant (R) strains fed a high NaCl diet, 11 beta-hydroxylase polymorphisms cosegregate with the adrenal capacity to synthesize 18-hydroxy-11-deoxycorticosterone (18-OH-DOC) and blood pressure. The R rat carries an 11 beta-hydroxylase allele that: (i) differs from those of 12 other rat strains; (ii) is associated with a uniquely reduced capacity to synthesize 18-OH-DOC; and (iii) encodes 5 amino acid substitutions in the 11 beta-hydroxylase protein. The robust salt-resistance of the Dahl R rat may be due in part to reduced synthesis of the mineralocorticoid 18-OH-DOC stemming from mutations in the 11 beta-hydroxylase gene. 11 beta-hydroxylase, located on rat chromosome 7, is the first candidate gene identified in an animal model in which coding sequence mutations have been linked to the regulation of blood pressure.

Single-strand conformation polymorphisms (SSCPs) detected in five bovine genes

Polymerase chain reaction (PCR) primers designed to amplify bovine specific sequences of the arginine-vasopressin (ARVP), glycoprotein hormone alpha (CGA), cytochrome oxidase c subunit IV pseudogene (COXP), prochymosin (CYM), coagulation factor X (F10), inhibin beta A (INHBA), low density lipoprotein receptor (LDLR) and oxytocin (OXT) genes in hybrid cells were used in a search for single strand conformation polymorphisms. DNA from 75 animals comprising crossbred and 7 purebred breeds were analysed. ARVP, COXP, CYM, LDLR and OXT were found to be polymorphic while CGA, F10 and INHBA were not. Polymorphic regions were identified within 206 bp of exon 1 of ARVP, 582 bp of the pseudogene COXP, 253 bp of exon 9 of CYM, 519 bp of LDLR cDNA and 160 bp of the upstream regulatory region of OXT. This is the first report of bovine polymorphisms for these genes and an important step in our goal to incorporate type I comparative anchor loci into the bovine linkage map. Polymorphic loci were subsequently analysed in pedigreed full-sib families and shown to be inherited in a Mendelian fashion.

Assignment of three rat integrin genes to chromosome 19 (ITGB1), chromosome 3 (ITGA4), and chromosome 7 (ITGA5)

By means of somatic cell hybrids segregating rat chromosomes, we determined the chromosome localization of three rat beta 1 family integrin genes. ITGB1 was assigned to Chromosome (Chr) 19, ITGA4 to Chr 3, and ITGA5 to Chr 7. These chromosome assignments reveal or confirm homology between two pairs of rat and human chromosomes (rat Chr 3-human Chr 2; rat Chr 7-human Chr 12).