Benutzerin:Kersti Nebelsiek/13
Champagne
International Champagne Horse Registry - Bildbeispiele für Pferde der Farbe Champagne Beschreibung der Farbe und Genetik vom Champagne-Gen http://www.champagnehorses.net/shades_of_champagne.htm
Mehrere Bilder von Rabicanos weitere Bilder Rabicano, Roan, Frame Overo, Flaxen
- Woolf CM.: Common white facial markings in Arabian horses that are homozygous and heterozygous for alleles at the A and E loci. J Hered. 1992 Jan-Feb;83(1):73-7. No abstract available. PMID: 1552160 http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=1552160&ordinalpos=7&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
Abstract Sabino (SB) is a white spotting pattern in the horse characterized by white patches on the face, lower legs, or belly, and interspersed white hairs on the midsection. Based on comparable phenotypes in humans and pigs, the KIT gene was investigated as the origin of the Sabino phenotype. In this article we report the genetic basis of one type of Sabino spotting pattern in horses that we call Sabino 1, with the alleles represented by the symbols SB1 and sb1. Transcripts of KIT were characterized by reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing cDNA from horses with the genotypes SB1/SB1, SB1/sb1, and sb1/sb1. Horses with the Sabino 1 trait produced a splice variant of KIT that did not possess exon 17. Genomic DNA sequencing of KIT revealed a single nucleotide polymorphism (SNP) caused by a base substitution for T with A in intron 16, 1037 bases following exon 16. The SNP associated with SB1 was designated KI16+1037A. This substitution eliminated a MnlI restriction site and allowed the use of PCR-RFLP to characterize individuals for this base change. Complete linkage was observed between this SNP and Sabino 1 in the Tennessee Walking Horse families (LOD = 9.02 for Θ = 0). Individual horses from other breeds were also tested. All five horses homozygous for this SNP were white, and all 68 horses with one copy of this SNP either exhibited the Sabino 1 phenotype or were multipatterned. Some multipatterned individuals appeared white due to the additive effect of white spotting patterns. However, 13 horses with other Sabino-type patterns did not have this SNP. Based on these results we propose the following: (1) this SNP, found within intron 16, is responsible for skipping of exon 17 and the SB1 phenotype, (2) the White and Sabino phenotypes are heterogeneous and this mechanism is not the only way to produce the pattern described as “Sabino” or “White,” and (3) homozygosity for SB1 results in a complete or nearly completely white phenotype.
- Fehler bei Vorlage * Pflichtparameter fehlt (Vorlage:FNZ): "2" Brooks SA, Bailey E: Exon skipping in the KIT gene causes a Sabino spotting pattern in horses. In: Mamm Genome. 2005 Nov;16(11):893-902. Epub 2005 Nov 11. PMID: 162848057{{{2}}}
Links
Splashed White Overo
Aussehen
Heterozygot
Ganz selten sind einfarbige Tiere ohne Abzeichen und mit braunen Augen. Manchmal weisen nur blaue Augen auf das Gen hin. Selten weist nur eine Schnippe auf das Gen hin.
Viele Genträger haben eine Blesse oder eine breite Laterne, die oft unregelmäßig ist und nach unten hin breiter wird. Auch Abzeichen an den Beinen sind oft vorhanden, aber meist weniger ausgeprägt als die am Kopf. Damit sind meist blaue, selten braune Augen verbunden.
Homozygot
Kopf mindestens eine breite Laterne, die nach unten hin breiter wird, weiße Beinabzeichen und weiße Flecken unterm Bauch.
Meist ist der ganze Kopf weiß, abgesehen von Mähnenansatz, Ohren und der Stelle wo der Kopf mit dem Hals verbunden ist. Von der Lendengegend aus (genau da wo Tobianos gewöhnlich schwarz sind) breitet sich ein weißer Flecke unterschiedlich weit und in unterschiedlicher Form aus.
Wenn ein Splashed White fast ganz weiß ist, sind meist noch Hals und Ohren dunkel.
Genetik
Splashed White
Splashed white is the least common of the spotting patterns in horses, although it is increasing in frequency as breeders use more and more splashed white horses in their breeding programs. It occurs sporadically in a number of widely divergent breeds, such as Welsh Ponies, Finnish Draft Horses, Icelandic Horses and Paints.
The pattern usually makes the horse look as though it has been dipped in white paint. On a dark horse, the effect can be that of an ice cream cone dipped in chocolate. The legs are usually white, as are the bottom portions of the body. The head is also usually white, and the eyes are frequently blue.
The edges of the white are consistently crisp and clean, with no roaning. Some of these splashed whites have dark toplines, but on some the white crosses the topline.
The splashed white pattern was originally studied in Finnish Horses, and was reputed to be a true recessive pattern. If this were the case, the pattern would be unlikely to occur unless two splashed white horses mated, which is not the case.
Recent evidence is consistent with this pattern being caused by a dominant gene. The main problem in the past appears to have been that minimally marked horses were classed as nonspotted, which resulted in erroneous conclusions.
Some people have observed that many splashed white horses are deaf. This is not much of a problem if the trainer realizes the limitations of the horse in question, and many of these horses go on to lead full, normal and productive lives. If trainers rely on many verbal cues, though, these horses will be labeled as difficult, stubborn, and can be psychologically ruined by techniques inappropriate for a deaf animal.
No homozygous splashed white horses have ever been documented, leading to the suspicion that this is yet another gene that cannot exist in homozygous form. If this is true, the loss of hearing probably occurs early in gestation rather than at term, so this is distinct from the lethal white foal problem where defective foals are born.
The best strategy for splashed white horses, then, is to mate them to horses without the splashed white pattern.
Splashed white horses generally have a continuous pattern of white on all four legs, chest and completely over the head.
- Splashed White, American Paint Horse Association 2007. http://www.apha.com/breed/geneticeq5.html
Results—Genotypes detected were homozygous Ile118, homozygous Lys118, and heterozygous. All foals with OLWS were homozygous for the Ile118Lys EDNRB mutation, and adults that were homozygous were not found. White patterning was strongly associated with EDNRB genotype. Color patterns with highest incidence (> 94%) of heterozygotes were frame overo, highly white calico overo, and frame blend overo. White-patterned bloodlines with lowest incidence of heterozygotes (< 21%) were tobiano, sabino, minimally white calico overo, splashed white overo, nonframe blend overo, and breeding-stock solid. The mutation was not detected in solid-colored horses from breeds without white patterning.
- Santschi EM, Vrotsos PD, Purdy AK, Mickelson JR.: Incidence of the endothelin receptor B mutation that causes lethal white foal syndrome in white-patterned horses. Am J Vet Res. 2001 Jan;62(1):97-103. PMID: 11197568
Taubheit
- Malte M. Harland, Allison J. Stewart, Arvle E. Marshall, and Ellen B. Belknap: Diagnosis of deafness in a horse by brainstem auditory evoked potential. Can Vet J. 2006 February; 47(2): 151–154. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1345730
Mischformen
Links
- Taktklar: Licht und Schatten - Schecken / Splashed White
- Englisch: Colormorgans: Splashed White
- Equine color genetics information: Splashed White
Sonstiges
Brindle, Dun Factor Striping, Palomino/Buckskin Striping, Foal Coat Striping, Coat Texturing, Dappling http://ultimatehorsesite.com/colors/colorgenes.htm alphabetische farbliste