Ocular associations of dappling (or merling) in the coat colour of dogs

Sorsby, Arnold; Davey, J. B.

doi:10.1007/bf02981535

Cited by 30 publications

(14 citation statements)

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“…Dogs having Mm and MM genotypes typically have blue eyes and often exhibit a wide range of auditory and ophthalmologic abnormalities (3). Reetz et al (4) studied the auditory capacity of Dachshunds and found that 54.6% of MM and 36.8% of Mm dogs had auditory dysfunction, ranging from mild to severe deafness.…”

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“…Klinckmann et al (5,6) conducted ophthalmologic studies with three groups of Dachshunds (MM, Mm, and mm) and found that merles and double merles had significantly greater frequencies of ocular abnormalities, including increased intraocular pressure and ametropic eyes. Microphthalmia and colobomas are well described in merle and double merle Dachshunds and Australian Shepherds (3,7,8). In all breeds, the double merle genotype can be sublethal and is associated with multiple abnormalities of the skeletal, cardiac, and reproductive systems (3,9,10).…”

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“…Microphthalmia and colobomas are well described in merle and double merle Dachshunds and Australian Shepherds (3,7,8). In all breeds, the double merle genotype can be sublethal and is associated with multiple abnormalities of the skeletal, cardiac, and reproductive systems (3,9,10). For these reasons, merle-to-merle breedings are strongly discouraged (9).…”

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Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog

Clark

Wahl

Rees

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

227

242

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Merle is a pattern of coloring observed in the coat of the domestic dog and is characterized by patches of diluted pigment. This trait is inherited in an autosomal, incompletely dominant fashion. Dogs heterozygous or homozygous for the merle locus exhibit a wide range of auditory and ophthalmologic abnormalities, which are similar to those observed for the human auditory-pigmentation disorder Waardenburg syndrome. Mutations in at least five genes have been identified as causative for Waardenburg syndrome; however, the genetic bases for all cases have not been determined. Linkage disequilibrium was identified for a microsatellite marker with the merle phenotype in the Shetland Sheepdog. The marker is located in a region of CFA10 that exhibits conservation of synteny with HSA12q13. This region of the human genome contains SILV, a gene important in mammalian pigmentation. Therefore, this gene was evaluated as a candidate for merle patterning. A short interspersed element insertion at the boundary of intron 10͞exon 11 was found, and this insertion segregates with the merle phenotype in multiple breeds. Another finding was deletions within the oligo(dA)-rich tail of the short interspersed element. Such deletions permit normal pigmentation. These data show that SILV is responsible for merle patterning and is associated with impaired function of the auditory and ophthalmologic systems. Although the mutant phenotype of SILV in the human is unknown, these results make it an intriguing candidate gene for human auditory-pigmentation disorders.short interspersed element ͉ pigmentation ͉ linkage disequilibrium

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Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog

Clark

Wahl

Rees

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

227

242

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“…Animals homozygous for the presumptive ancestral or wild type allele m are normally pigmented. Characteristically, small patches of normal color appear within areas of diluted pigmentation in both MM and Mm dogs [10]. Dogs having the merle genotype but not expressing the merle phenotype are known as cryptic merles (represented here by Mcm) [4].…”

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confidence: 99%

Identification of Cryptic Allele for Merle Patterning in Dogs by Molecular Genetics Methods / Identifikacija Skrivenog Alela Za Mramoriranu Šaru Pasa Pomoću Metoda Molekularne Genetike

et al. 2015

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Merle patterning in dogs, caused by the insertion of a short interspersed element (SINE) in the genetic structure of SILV gene, is characterized by patches of diluted pigment intermingled with normal melanin. Sequencing analyses of SINE element localized in the canine SILV gene discovered a variability of the poly (A)-tail length which is responsible for the different expression of merle pattern. The SINE element with the length of poly(A)-tail between 91 -101 nucleotides is responsible for the merle phenotype with all characters of merle pattern. On the contrary the dogs which have SINE element with the shorter length of poly(A) tail between 54-65 nucleotides are referred as cryptic merles without expresion of Merle pattern. The aim of this study was to improve molecular genetics method for the detection of cryptic allele for merle patterning in dogs. A total of 40 dogs of four breeds -Border collie, Shetland sheepdog, Australian Shepherd dog, and Chihuahua were used in this study. Canine genomic DNA was isolated from samples of whole blood and buccal cells by commercial column kit. Detection of merle (M), cryptic merle (Mc) and non-merle (m) alleles was done using M13-tailed primer protocol and two different allele-sizing methods for the verifi cation of the electrophoresis result. In the analyzed population of dogs were detected 20 dogs with non-merle genotype mm, 17 dogs with merle genotype Mm, 2 dogs with double merle genotype MM and one dog with merle phenotype but with the presence of cryptic merle allele Mc with the consequential genotype MMc.

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“…lV,17 (aged 29) was normal (interocular measures: 32, 63 and 90 mm) and had six unaffected children (V, [12][13][14][15][16][17].…”

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confidence: 99%

Waardenburg's Syndrome in Father and Daughter

Thorkilgaard

1962

Acta Ophthalmologica

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In 1950-51, Waardenburg (15,16,17) showed that some well-known developmental anomalies in the interocular region associated with deafness and certain pigmentary defects constitute a syndrome which is inherited as a dominant character. The syndrome consists of the following features: lateroverse dystopia of the medial canthi (estimated penetrance, 99 O/O), prominent nose root (78 O / o ) , hyperblasia of the medial part of the eyebrows with frequent overgrowth (synophrys) (45 O/O), heterochromia iridum (25 O/O), unilateral deafness or deafmutism (20 U/O), a white hair lock (17 O/O) and, in some cases, vitiligo-like pigmentary defects of the skin. Premature greying of the scalp hair is, according to Waardenburg, equivalent to the white hair lock.After having shown that the characteristic features of the syndrome are normal at the beginning of the third month of embryonic life, Waardenburg expressed the view that the syndrome owes its features to a fixation of the foetal characters through an arrest of normal development (14).A number of single cases have been published, including a sporadic one by the Danish investigator Brtendstrup (3) in 1941. An interesting divergent case with extensive vitiligo, cranial deformities and multiple dysplasia of the upper extremities was presented by Klein ( 8 ) in 1950. Keizer (7) and Wildervanck (13) added several Dutch families to the nine considered by Waardenburg. Other families have been described from Switzerland (2), France (lo), England (9, l l ) , Denmark (Arnvig (l)), Spain (6) and the U. S. A., where Di George et al. ( 4 ) presented the first cases among Negroes.These are of particular interest, since some of the patients had double-sided blue eyes, i. e. bilateral hypochromia of the irides.In histological studies of affected internal ears, Fisch ( 5 ) revealed the absence of the organ of Corti and of the greater part of the ganglion cells of the spiral ' $) Received October 12th 1962.

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Ocular associations of dappling (or merling) in the coat colour of dogs

Cited by 30 publications

References 9 publications

Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog

Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog

Identification of Cryptic Allele for Merle Patterning in Dogs by Molecular Genetics Methods / Identifikacija Skrivenog Alela Za Mramoriranu Šaru Pasa Pomoću Metoda Molekularne Genetike

Waardenburg's Syndrome in Father and Daughter

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