Inheritance of coat colour in the Hovawart dog

The three recognised colour varieties of the Hovawart breed of dog, black, black and gold and blonde, are due primarily to combinations of the mutant alleles solid black (A ^s ), black and tan (a ^t ) of the agouti series and the non-extension of black allele (e). The e allele is epistatic to the agouti alleles, thereby reducing the four possible phenotypes to three.     

Inheritance of coat colour in the Anatolian Shepherd dog

The predominant colour of the Anatolian Shepherd dog varies from a dark fawn to light red, with a variable black muzzle and face (mask). Evidence is presented that the colour is due to the dominant yellow allele (A ^y) of the agouti locus. Two other frequent colours are white spotting, due to the piebald allele (s ^p), and the chinchilla allele (ch). Two rarer colours are the agouti wolf-grey wild type (A ⁺) and a light fawn with a blue facial mask, due to the dilution allele (d).     

Inheritance of colour and coat in the Belgian Shepherd dog

The several colours and coats of the Belgian Shepherd dog are shown to be due primary to combinations of the following genes: dominant black (A ^s ), dominant yellow (A ^y ), chinchilla (ch), long hair (l) and wire hair (Wh). The gene for black and tan (a ^t ) is or has been present in the breed. All of the dominant yellow dogs exhibit a black facial mask and extensive suffusion of black guard hairs on the body.     

Behavioural reactivity of the Korean native Jindo dog varies with coat colour

This study aimed to compare the behavioural reactivity of Jindo dogs with two different coat colours. Fawn (16 males, 15 females; mean age ± S.D. = 7.2 ± 2.1 years) and white (10 males, 10 females; mean age ± S.D. = 6.9 ± 2.1 years) Jindo dogs were exposed to a set of behavioural tests. All of the dogs were videotaped during the testing period to allow further analysis. The intensity of social, aggressive, fearful, and submissive reactivity and the frequency of urination as a scent-marking behaviour were scored on a scale running from 0 to 4 points. For each dog, each variable was defined as the average of the scores of nine behaviour tests. Then, the behavioural reactivities of Jindo dogs of each coat colour were compared. The results suggested that Jindo dogs of fawn coat colour exhibited a significantly lower intensity of fearful and submissive reactivity than those of white coat colour. In addition, fawn Jindo dogs produced scent-marking behaviour significantly more frequently. The results of the present study may provide useful information for scientific researchers, potential owners and breeders of Jindo dogs.     

An investigation into the genetic background of coat colour dilution in a Charolais x German Holstein F2 resource population

The molecular background of many loci affecting coat colour inheritance in cattle is still incompletely characterized, although it is known that coat colour results from the joint effects of several loci, e.g. agouti, extension and dilution. Dilution alleles are responsible for a dilution effect on the original coat colour of an individual, which is determined by the agouti and extension loci. Different loci affecting dilution of pigment are suggested in Charolais (Dc) and Simmental (Ds). To enable chromosomal mapping of the Dc mutation, 133 animals from an F2 full-sib resource population generated from a cross of Charolais and German Holstein were scored for the coat colour dilution phenotype. Linkage analysis covering all autosomes revealed a significant linkage of the dilution phenotype with microsatellite markers on bovine chromosome 5. No recombination was observed between marker ETH10 and the Dc locus. Positional and functional information identified the bovine silver homolog (SILV) gene as a candidate for the Dc mutation. Results from comparative sequencing of the SILV gene in individuals with different dilution coat colour phenotypes confirmed the presence of a c.64G>A non-synonymous mutation, which had previously been identified in the Charolais breed. The alleles at this locus were associated with coat colour dilution in this study. However, further investigation of colour inheritance within the F2 resource population indicated that a single diallelic mutation in the SILV gene cannot explain the total observed variation of coat colour dilution.     

A novel KIT deletion variant in a German Riding Pony with white‐spotting coat colour phenotype

White spotting phenotypes in horses may be caused by developmental alterations impairing melanoblast differentiation, survival, migration and/or proliferation. Candidate genes for white‐spotting phenotypes in horses include EDNRB, KIT, MITF, PAX3 and TRPM1. We investigated a German Riding Pony with a sabino‐like phenotype involving extensive white spots on the body together with large white markings on the head and almost completely white legs. We obtained whole genome sequence data from this horse. The analysis revealed a heterozygous 1273‐bp deletion spanning parts of intron 2 and exon 3 of the equine KIT gene (Chr3: 79 579 925–79 581 197). We confirmed the breakpoints of the deletion by PCR and Sanger sequencing. Knowledge of the functional impact of similar KIT variants in horses and other species suggests that this deletion represents a plausible candidate causative variant for the white‐spotting phenotype. We propose the designation W28 for the mutant allele.     

Harlequin colour in the Great Dane dog

Breeding data from Eire and Great Britain confirm the hypothesis of Sponenberg (1985) that the harlequin colour of the Great Dane breed of dog is due the combined action of a dominant gene H with the merle gene M in the genotype H+M +. The typical bluish coloration induced by M is modified to white by the action of H. The H gene is a prenatal lethal when homozygous HH and this study offers clear indication that the heterozygous H + interacts with M to reduce the viability of white merle homozygotes H+MM.     

Inheritance of malathion resistance in the German cockroach

Malathion resistance in the German cockroach has been examined with respect to its inheritance pattern and linkage relationship. A resistant strain was crossed reciprocally with an unmarked and two marked susceptible strains. The progeny from F1, F2 and backcrosses were tested for resistance to malathion by exposure to toxicant-impregnated filter paper, and were classified according to marker traits where appropriate. Malathion resistance (R-Mal) is inherited as a simple autosomal dominant trait. Linkage studies showed R-Mal to be independent of or in group IV, pld in group VI, and T(9, 10) Pw marking both groups III and VIII. A possible malathion-resistance mechanism for this insect is discussed.

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Résumé La résistance de la Blatte germanique au malathion est réputée se manifester à la fois dans les conditions naturelles et dans les lignées élevées en laboratoire. Dans le présent travail cette résistance est étudiée en vue de déterminer le mécanisme de sa transmission héréditaire et de commencer à établir la carte chromosomique de ce caractère. Une lignée présentant un haut niveau de résistance au malathion est croisée avec une lignée sensible non marquée et avec deux autres lignées sensibles possédant un gêne marqueur. Les descendants de F1, de F2 et des croisements de retour sont testés pour leur résístance au malathion en soumettant les larves à un contact avec du papier filtre imprégné de malathion; ils sont classés en se rapportant aux caractères marqueurs. Les gênes marqueurs utilisés sont or sur le groupe IV, pld sur le groupe VI, et T(9, 10) Pw, marquant à la fois les groupes III et VIII. Les résultats montrent que les descendants F1 provenant de croisements réciproques sont identiques et ressemblent au parent résistant. Cette donnée ajoutée aux résultats concernant F2 et les croisements de retour avec les parents R et S, indique que la résistance au malathion est transmise comme un caractère dominant, monofactoriel et porté sur un autosome, caractère désigné R-Mal. Les études relatives au linkage du caractère R-Mal aves les gênes marqueurs, ont montré l'indépendance de R-Mal. II est suggéré que le mécanisme le plus probable de la résistance au malathion résulte d'une activité accrue de la carboxyesterase.

     

Comparative linkage mapping of the Grey coat colour gene in horses

Grey horses are born coloured, turn progressively grey and often develop melanomas late in life. Grey shows an autosomal dominant inheritance and the locus has previously been mapped to horse chromosome 25 (ECA25), around the TXN gene. We have now developed eight new single nucleotide polymorphisms (SNPs) associated with genes on ECA25 using information on the linear order of genes on human chromosome 9q, as well as the human and mouse coding sequences. These SNPs were mapped in relation to the Grey locus using more than 300 progeny from matings between two Swedish Warmblood grey stallions and non-grey mares. Grey was firmly assigned to an interval with flanking markers NANS and ABCA1. This corresponds to a region of approximately 6.9 Mb on human chromosome 9q. Furthermore, no recombination was observed between Grey, TGFBR1 and TMEFF1, the last two being 1.4 Mb apart in human. There are no obvious candidate genes in this region and none of the genes has been associated with pigmentation disorders or melanoma development, suggesting that the grey phenotype is caused by a mutation in a novel gene.     

German rex: A rexoid coat mutant in the cat

A rexoid coat mutant was discovered in Berlin in 1951; the second of its kind in the cat. The coat is short and soft to the touch. Breeding data show that it is inherited as an autosomal recessive. The German rex is phenotypically similar to the English rex but represents a distinct mutational event.