A new Finnish flavor of feline coat coloration, "salmiak," is associated with a 95-kb deletion downstream of the KIT gene.

Cats with a distinctive white hair pattern of unknown molecular cause have been discovered in the Finnish domestic cat population. Based on the unique appearance of these cats, we have named this phenotype salmiak ("salty licorice"). The use of a commercially available panel test to genotype four salmiak-colored cats revealed the absence of all known variants associated with white-haired phenotypic loci: full White (W), Spotting (Ws) and the Birman white Gloves associated (wg) allele of the KIT proto-oncogene (KIT) gene. Whole-genome sequencing on two salmiak-colored cats was conducted to search for candidate causal variants in the KIT gene. Despite a lack of coding variants, visual inspection of the short read alignments revealed a large ~95 kb deletion located ~65 kb downstream of the KIT gene in the salmiak cats. Additional PCR genotyping of 180 domestic cats and three salmiak-colored cats confirmed the homozygous derived variant genotype fully concordant with the salmiak phenotype. We suggest the newly identified variant be designated as wsal for "w salmiak".

Efficient generation of cloned cats with altered coat colour by editing of the KIT gene.

Coat colour largely determines the market demand for several cat breeds. The KIT proto-oncogene (KIT) gene is a key gene controlling melanoblast differentiation and melanogenesis. KIT mutations usually cause varied changes in coat colour in mammalian species. In this study, we used a pair of single-guide RNAs (sgRNAs) to delete exon 17 of KIT in somatic cells isolated from two different Chinese Li Hua feline foetuses. Edited cells were used as donor nuclei for somatic cell nuclear transfer (SCNT) to generate cloned embryos presenting an average cleavage rate exceeding 85%, and an average blastocyst formation rate exceeding 9.5%. 131 cloned embryos were transplanted into four surrogates, and all surrogates carried their pregnancies to term, and delivered 4.58% (6/131) alive cloned kittens, with 1.53% (2/131) being KIT-edited heterozygotes (KITD17/+). The KITD17/+ cats presented an obvious darkness reduction in the mackerel tabby coat. Immunohistochemical analysis (IHC) of skin tissues indicated impaired proliferation and differentiation of melanoblasts caused by the lack of exon17 in feline KIT. To our knowledge, this is the first report on coat colour modification of cats through gene editing. The findings could facilitate further understanding of the regulatory role of KIT on feline coat colour and provide a basis for the breeding of cats with commercially desired coat colour.

Genomic regions associated with coat color in Gir cattle.

Indicine cattle breeds are adapted to the tropical climate, and their coat plays an important role in this process. Coat color influences thermoregulation and the adhesion of ectoparasites and may be associated with productive and reproductive traits. Furthermore, coat color is used for breed qualification, with breeders preferring certain colors. The Gir cattle is characterized by a wide variety of coat colors. Therefore, we performed genome-wide association studies to identify candidate genes for coat color in Gir cattle. Different phenotype scenarios were considered in the analyses and regions were identified on eight chromosomes. Some regions and many candidate genes are influencing coat color in the Gir cattle, which was found to be a polygenic trait. The candidate genes identified have been associated with white spotting patterns and base coat color in cattle and other species. In addition, a possible epistatic effect on coat color determination in the Gir cattle was suggested. This is the first published study that identified genomic regions and listed candidate genes associated with coat color in Gir cattle. The findings provided a better understanding of the genetic architecture of the trait in the breed and will allow to guide future fine-mapping studies for the development of genetic markers for selection.

Premature gray hair development in the interbrow region owing to the loss of maxillary first molars in young mice.

The exact sites of premature hair graying and whether tooth loss causes this condition remain unknown. In this study, we aimed to explore the effect of reduced mastication on premature hair graying. Maxillary first molars were extracted from young mice, and the mice were observed for 3 months, along with non-extraction control group mice. After 3 months, gray hair emerged in the interbrow region of mice in the tooth extraction group but not in the control group. The expression of tyrosinase-related protein-2 (TRP-2) mRNA was lower in the interbrow tissues of young mice without maxillary molars than in those with maxillary molars. Tooth loss leads to interbrow gray hair growth, possibly because of weakened trigeminal nerve input, suggesting that reduced mastication causes premature graying. Thus, prompt prosthetic treatment after molar loss is highly recommended.

Canine coat color E locus updates: Identification of a new MC1R variant causing 'sable' coat color in English Cocker Spaniels and a proposed update to the E locus dominance hierarchy.

The coat color phenotype 'sable' occurs in the English Cocker Spaniel dog breed. It closely resembles other canine color patterns known as domino/grizzle/pied (eA allele) and grizzle/domino (eG allele) determined by variants in the melanocortin 1 receptor gene (MC1R; 'extension' or E locus), a key multi-allele regulator of coat color. We examined genetic variation in MC1R, and found one new non-synonymous variant, c.250G>A (p.(Asp84Asn)), consistently associated with the English Cocker Spaniel 'sable' phenotype. We propose calling this newly identified allele eH and further show that the eA , eH and eG (previously known as EG ) alleles associate with similar phenotypes in dogs impacting genotypes regulated by beta-defensin 103 gene (CBD103; K locus) and agouti signaling protein gene (ASIP; A locus) in the absence of the EM and E alleles. This suggests that all three alleles are putative reduced-function variants of the MC1R gene. We propose the revised and updated E locus dominance hierarchy to be EM > E > eA /eH /eG > e1-3 .

Zinc deficiency or genetic mutations?-A case report of hair heterochromia in the context of MC1R genetic mutations.

Hair heterochromia may be caused by different mechanisms. At clinical work, we found a Chinese boy whose hair colour gradually turned to red. We record the diagnosis and treatment process and follow-up situation, finally find that altered hair colour phenotype is due to MC1R genetic mutations, rather than zinc deficiency. This rarely red hair colour phenotype improve our understanding of hair heterochromia caused by genetic mutations.

Hair color, family history of melanoma, and the risk of Parkinson's disease: An analysis update.

BACKGROUND: A shared biological component between melanoma and Parkinson's disease (PD) has been suggested. Yet, epidemiological evidence is scarce. OBJECTIVE: To examine the association of hair color and family history of melanoma, two strong predictors of melanoma risk, with the occurrence of PD. METHODS: We followed 131,342 women and men for ∼30 years for the development of PD. We calculated the cumulative incidence of PD from ages 40 to 90 according to hair color, and estimated the hazard ratio of PD according to hair color and family history of melanoma. RESULTS: Hair color was not strongly associated with the risk of PD, especially at advanced ages. In contrast, individuals with a family history of melanoma had a 1.4-fold higher risk of PD compared to those without a history. CONCLUSIONS: Our results support the hypothesis of a shared biological component between PD and melanoma. Both pigmentary and non-pigmentary pathways may play a role.

Natural hair color and skin cancers: A two-sample Mendelian randomization study.

Previous observational studies have indicated an association between hair color and the risk of melanoma and keratinocyte skin cancer (KSC); however, different hair colors show inconsistent effects on skin cancers. Here, we conducted a two-sample Mendelian randomization (MR) study to evaluate the causal relationship between natural hair color and skin cancers by using 211 single nucleotide polymorphisms as genetic instruments from a genome-wide meta-analysis of 360,270 individuals of European ancestry. Light hair colors (red, blonde, and light brown) were associated with high levels of cutaneous melanoma (CM) and KSC (CM-inverse variance weighted [IVW] odds ratio [OR]-red: 1.034, 95% confidence interval [CI]: 1.025-1.044, P < 0.001; OR-blonde: 1.008, 95% CI: 1.003-1.014, P = 0.003; OR-light brown: 1.006, 95% CI: 1.002-1.011, P = 0.009; KSC-IVW OR-red: 1.078, 95% CI: 1.053-1.103, P < 0.001; OR-blonde: 1.024, 95% CI: 1.009-1.040, P = 0.002; OR-light brown: 1.018, 95% CI: 1.004-1.033, P = 0.01). However, dark brown hair showed an inverse causal relationship with skin cancers (CM IVW OR: 0.987, 95% CI: 0.984-0.990, P < 0.001; KSC IVW OR: 0.979, 95% CI: 0.970-0.988, P < 0.001). Black hair was associated with a decreased risk of KSC (IVW OR: 0.954, 95% CI: 0.913-0.997, P = 0.036) but showed no causal relationship with CM. The present study provides strong MR evidence of a causal association between hair color and skin cancer. Secondary MR analyses enhances result robustness by replicating findings, exploring gender-specific effects, and providing a more comprehensive understanding of the complex relationship between hair color and skin cancers. More large-scale MR studies or randomized controlled trials are required to further investigate the mechanisms of the association between hair color and skin cancers.

DNA Molecular Identification of Human Phenotypic Characteristics--New Progress Over the Past Five Years / 法医学杂志

Molecular identification of human externally visible characteristic （EVC）, which is also called forensic DNA phenotyping （FDP）, can serve as a "molecular witness" when the routine investigations can not determine the identity of a criminal and the DNA database find no match after comparison. FDP could assist in investigation of cases by inferring the externally visible phenotypic characteristics from DNA obtained from the biological materials left at crime scenes, or unknown corpses. In the last few years, studies on the selection of EVC related molecular markers have been reported frequently and some of the EVCs could already be inferred with a certain accuracy, such as hair color and iris color. Further fundamental research on molecular genetics of human external phenotypic characteristics, as well as the continuous innovation on molecular biological technology would promote the rapid development of DNA molecular identification of human phenotypic characteristics.

Griscelli syndrome-type 2 in twin siblings: case report and update on RAB27A human mutations and gene structure

Griscelli syndrome (GS) is a rare autosomal recessive disorder caused by mutation in the MYO5A (GS1, Elejalde), RAB27A (GS2) or MLPH (GS3) genes. Typical features of all three subtypes of this disease include pigmentary dilution of the hair and skin and silvery-gray hair. Whereas the GS3 phenotype is restricted to the pigmentation dysfunction, GS1 patients also show primary neurological impairment and GS2 patients have severe immunological deficiencies that lead to recurrent infections and hemophagocytic syndrome. We report here the diagnosis of GS2 in 3-year-old twin siblings, with silvery-gray hair, immunodeficiency, hepatosplenomegaly and secondary severe neurological symptoms that culminated in multiple organ failure and death. Light microscopy examination of the hair showed large, irregular clumps of pigments characteristic of GS. A homozygous nonsense mutation, C-T transition (c.550C>T), in the coding region of the RAB27A gene, which leads to a premature stop codon and prediction of a truncated protein (R184X), was found. In patient mononuclear cells, RAB27A mRNA levels were the same as in cells from the parents, but no protein was detected. In addition to the case report, we also present an updated summary on the exon/intron organization of the human RAB27A gene, a literature review of GS2 cases, and a complete list of the human mutations currently reported in this gene. Finally, we propose a flow chart to guide the early diagnosis of the GS subtypes and Chédiak-Higashi syndrome.

Color-dilution alopecia in dogs

Color-dilution alopecia is a relatively uncommon hereditary skin disease seen in "Blue" and other color-diluted dogs. This syndrome is associated with a color-dilution gene. The initial clinical signs are the gradual onset of a dry, dull and poor hair coat quality. Hair shafts and hair regrowth are poor, and follicular papules may develop and progress to frank comedones. Hair loss and comedo formation are usually most severe on the trunk, especially color-diluted area on the skin. Six cases of color-dilution alopecia are reported in 3 months to 10 years old dogs. The breeds of dogs are blue Doberman Pinscher, Miniature Pinscher, Dachshund, and Schnauzer. Grossly, extensive partial hair loss was seen on the skin. Histopathologically, the epidermis is relatively normal but may be hyperplastic. Hair follicles are characterized by atrophy and distortion. Heavily clumped melanin is present in the epidermis, dermis and hair follicles.

Marcaçäo fenotípica para cor e padräo de pelagem em Rattus norvegicus - I / Phenotypic marking for pattern and coat color Rattus norvegicus - I

A cor e padräo de pelagem em Rattus norvegicus säo fenótipos de mais fácil identificaçäo prática deste animal. A seleçäo de matrizes genotipicamente definidas para estes fenótipos foi obtida a partir de ratos Wistar e Long Evans, submetidos a cruzamentos experimentais, seguidos de cruzamentos-teste. Tais matrizes foram utilizadas para iniciar uma série de cruzamentos endogâmicos (cinco geraçöes consecutivas; incrossing = 67.2 por cento), com a finalidade de serem posteriormente comparadas entre si e a um grupo controle, inicialmente quanto aos efeitos da consangüinidade. A análise dos resultados permitiu concluir que tais efeitos levaram a uma reduçäo da fertilidade nas linhagens selecionadas, o que näo se verificou no grupo controle, mesmo submetido a endogamia.