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At least 19 recordsLinked to original sources
PubMed2025

A Comprehensive Review of GWASs of Human Hair Traits.

Hair traits are nonpathogenic features that vary among individuals. Unlike hair follicle (HF) diseases, which are rare in the population, hair traits can be measured in everyone. This facilitates the construction of large cohorts that are well-powered for gene discovery. GWASs identify genetic variants that are widely shared among people globally, providing knowledge with broad population relevance. We compile findings from hair trait GWASs to deepen our understanding of HF biology. In reviewing genetic factors that influence hair traits, we demonstrate overlap with disease genes, underscoring that genetic studies of traits improve our knowledge about health and disease.

Humans↗
PubMed1999

Mycorrhizal status of the genus Carex (Cyperaceae).

The Cyperaceae have generally been considered nonmycorrhizal, although recent evidence suggests that mycotrophy may be considerably more widespread among sedges than was previously realized. This study surveyed 23 species of Carex occurring in upland and wetland habitats in northeastern Illinois. Mycorrhizal infection by arbuscular fungi was found in the roots of 16 species of Carex and appears to occur in response to many factors, both environmental and phylogenetic. While some species appear to be obligately nonmycorrhizal, edaphic influences may be responsible for infection in others. In five of the seven Carex species that were nonmycorrhizal, a novel root character, the presence of bulbous-based root hairs, was identified. The taxonomically patchy distribution of the distinctive root hair trait suggests that these structures may have evolved several times within the genus. Evidence of multiple independent origins of the root hair trait lends support to the hypothesis that root hairs represent an adaptation to nonmycotrophy. Although taxonomic position does seem to be of importance in determining the mycorrhizal dependence of sedges, the pattern may be a patchwork of both mycorrhizal clades and clades that have adapted to the nonmycorrhizal state.

Journal Article↗
PubMed1994

Determination of haemophilia A carrier status from hair samples using polymerase chain reaction technique.

The usefulness of intragenic restriction fragment length polymorphisms (RFLPs) for BclI, HindIII and XbaI, adapted for polymerase chain reaction (PCR), was tested for the detection of haemophilia A carrier status in the consultant of a family in which only haematological information was available on the inheritance of the trait. Hair follicles were used as the non-invasive source of DNA. The mother was found to be homozygous for BclI and heterozygous for HindIII sites, whereas her status as regards informativeness could not be established for XbaI. On the basis of HindIII RFLP, the daughter was found to be a carrier of the haemophilia trait. This was confirmed by sequencing the amplified intron 19 of the mother and the daughter. The RFLP for XbaI did not appear to be suitable for carrier detection using PCR due to the difficulty of establishing homozygosity or heterozygosity from the results of digestion of the amplified product.

Base Sequence↗
PubMed1987

Biology of the people of Sikkim, India. 2. Colour blindness, ear lobe attachment, mid-phalangeal hair and behavioural traits.

14 population groups of Sikkim (India)--Lepchas (2), Bhutias (2), Sherpas, Tamangs, Gurungs, Mangars, Rais, Limboos/Subbas, Pradhans (Newars), Brahmans, Chhetris, Scheduled Castes--have been studied in regard of the intra- and intergroup variability of colour blindness, ear lobe attachment, mid-phalangeal hair and behavioural traits (tongue folding, hand clapsing, arm folding, leg folding, handedness). Some of these variables show a considerable distribution heterogeneity, which is discussed considering history and marriage patterns of these populations. As most of them are highly endogamous one can assume that this heterogeneity is caused by locally acting factors such as drift and/or founder effects, which could be preserved due to as good as lacking gene flow among the populations under study. Beyond that the Sikkim data are compared briefly with those reported for other Indian and Asiatic populations.

Color Vision Defects↗
PubMed2006

Multiple quantitative trait loci modify cochlear hair cell degeneration in the Beethoven (Tmc1Bth) mouse model of progressive hearing loss DFNA36.

Dominant mutations of transmembrane channel-like gene 1 (TMC1) cause progressive sensorineural hearing loss in humans and Beethoven (Tmc1Bth/+) mice. Here we show that Tmc1Bth/+ mice on a C3HeB/FeJ strain background have selective degeneration of inner hair cells while outer hair cells remain structurally and functionally intact. Inner hair cells primarily function as afferent sensory cells, whereas outer hair cells are electromotile amplifiers of auditory stimuli that can be functionally assessed by distortion product otoacoustic emission (DPOAE) analysis. When C3H-Tmc1Bth/Bth is crossed with either C57BL/6J or DBA/2J wild-type mice, F1 hybrid Tmc1Bth/+ progeny have increased hearing loss associated with increased degeneration of outer hair cells and diminution of DPOAE amplitudes but no difference in degeneration of inner hair cells. We mapped at least one quantitative trait locus (QTL), Tmc1m1, for DPOAE amplitude on chromosome 2 in [(C/B)F1xC]N2-Tmc1Bth/+ backcross progeny, and three other QTL on chromosomes 11 (Tmc1m2), 12 (Tmc1m3), and 5 (Tmc1m4) in [(C/D)F1xC]N2-Tmc1Bth/+ progeny. The polygenic basis of outer hair cell degeneration in Beethoven mice provides a model system for the dissection of common, complex hearing loss phenotypes, such as presbycusis, that involve outer hair cell degeneration in humans.

Animals↗
PubMed1986

Genetic studies of Pangwalas, Transhumant and Settled Gaddis. 4. Colour blindness, mid-phalangeal hair, ear lobe attachment and behavioural traits.

Frequency distributions of colour blindness, midphalangeal hair, ear lobe attachment, hand clasping, arm folding, leg folding and handedness are reported for different population groups from Himachal Pradesh, North India, namely Pangwalas, Transhumant Gaddis (Brahmans, Rajputs and Scheduled Castes) and Settled Gaddis (Brahmans, Rajputs and Schedules Castes). An attempt has been made to compare the results of the present study within and between these groups as well as with the results of other reports from different population groups of India and Asia.

Color Vision Defects↗
PubMed2005

Melanocortin-1 receptor (MC1R) gene variants and dysplastic nevi modify penetrance of CDKN2A mutations in French melanoma-prone pedigrees.

Germline mutations in CDKN2A gene predispose to melanoma with high but incomplete penetrance. Penetrance of CDKN2A gene was found to be significantly influenced by host factors (nevus phenotypes and sunburn) on one hand and by variants of MC1R gene (RHC variants consistently associated with red hair and fair skin) on the other hand. Our goal was to examine the joint effects of MC1R variants and other potential risk factors [total nevi, dysplastic nevi, pigmentary traits (skin, hair and eye color), skin reactions to sunlight, and degree of sun exposure] on CDKN2A penetrance. Clinical, genetic, and covariate data were recorded in 20 French melanoma-prone families with cosegregating CDKN2A mutations. Analysis of the cotransmission of melanoma and CDKN2A mutations was conducted by likelihood-based methods using the regressive logistic models, which can account for a variation of disease risk with age and can include the aforementioned risk factors as covariates. RHC variants, considered either alone or in the presence of pigmentation and nevus phenotypes, were found to increase significantly CDKN2A penetrance. Multivariate analysis, using a stepwise selection procedure, showed significant effects of two factors on melanoma risk in CDKN2A mutations carriers: RHC variants [odds ratio of hazard function (OR), 2.21; P = 0.03] and dysplastic nevi (OR, 2.93; P < 0.01). Such results may have important consequences to improve the prediction of melanoma risk in families.

Adult↗
PubMed1999

Mapping complex traits in diseases of the hair and skin.

The past decade has witnessed the ascendance of human genetics in modern medicine, and at the forefront of this movement is the identification of genetic factors underlying inherited diseases. The methods of genetic mapping and positional cloning have made the discovery of genes with alleles that cause simple Mendelian diseases commonplace. The elucidation of the genetic basis of such disorders has vitalized both human genetics and the entire medical community as the field has gained prominence. The fact remains, however, that diseases resulting from the action of alleles of a single gene comprise only a minor percentage of traits that are medically relevant to humanity. The majority of these are multifactorial "complex traits", which result from the aggregate contribution of an unknown number of genes interacting with each other and with the environment. The current challenge has become one of parlaying successes in the mapping of Mendelian diseases into the discovery of genes whose alleles predispose the development of a complex disease. In light of this challenge, this review summarizes the methods and addresses some of the central issues of complex trait mapping, while using examples from dermatologically-relevant complex traits such as psoriasis and alopecia. Additionally, current technical and theoretical advances as well as the potential impact of the Human Genome Project will be discussed.

Animals↗
PubMed2005

A 1927 study supports a current genetic model for inheritance of human scalp hair-whorl orientation and hand-use preference traits.

The basis of right- vs. left-hand-use preference in humans has been debated for a long time. Culturally learned, birth stress, and biologically specified causes are the prominent etiologies under consideration. A 2003 (Klar 2003) study reported a correlation between a person's preferred hand and the scalp hair-whorl orientation developed on the head. By reinterpreting results of a 1927 (Schwarzburg 1927) study on the genetics of the hair-whorl trait, support for a recent single gene, two-allele "random-recessive model" for both hair-whorl orientation and handedness trait inheritance is demonstrated.

Alleles↗
PubMed1998

Demographic characteristics, pigmentary and cutaneous risk factors for squamous cell carcinoma of the skin: a case-control study.

We conducted a case-control study of squamous cell carcinoma of the skin (SCC) in a cohort of people followed from 1987 to 1994. Subjects were residents of Geraldton, Western Australia, who were between 40 and 64 years of age in 1987. On 2 occasions, in 1987 and 1992, dermatologists examined participants for skin cancers. Subjects were also asked on several occasions about skin cancers that they had had treated. Migrants to Australia had reduced risks of SCC. Furthermore, people who migrated to Australia early in life or, equivalently, lived in Australia for a long time had a higher risk than immigrants who arrived later in life or more recently. People who had southern European ancestry had a much lower risk of SCC than other subjects, most of whom were of British or northern European origin. Among Australian-born subjects of British or northern European ancestry, the skin's sensitivity to sunlight was strongly associated with SCC. The pigmentary traits of hair colour, eye colour and skin colour showed weaker associations. The degree of freckling on the arm was strongly predictive of risk. The risk of SCC increased strongly with increasing evidence of cutaneous solar damage and was most strongly associated with the number of solar keratoses. Our results show that sensitivity to sunlight and high levels of exposure to sunlight are important determinants of the risk of SCC.

Adult↗
PubMed2004

Rhizoplane colonisation of peas by Rhizobium leguminosarum bv. viceae and a deleterious Pseudomonas putida.

Pseudomonas putida strain A313, a deleterious rhizosphere bacterium, reduced pea nitrogen content when inoculated alone or in combination with Rhizobium leguminosarum bv. viceae on plants in the presence of soil under greenhouse conditions. When plants were grown gnotobiotically in liquid media, mixed inocula of A313 and rhizobia gave a higher proportion of small evenly distributed nodules when compared with a single rhizobial inoculation. In addition, the rhizobial root establishment was reduced by A313 irrespective of inoculum density, indicating that A313 has the capacity to interact with the early rhizobial infection process. When pea seedlings were simultaneously inoculated with A313 and rhizobia, A313 colonised the root hairs to the same extent as the rhizobia, according to analysis by immunofluorescence microscopy. This suggests that the root hair colonisation trait of P. putida interferes with the onset of the symbiotic process.

Analysis of Variance↗
PubMed1978

A new familial defect in neutrophil bactericidal activity.

A 4-year-old boy with recurrent infections and his clinically healthy father showed a severe, isolated defect in bactericidal activity of peripheral neutrophil leukocytes (the mother and the only sister were normal). Lymph nodes, spleen and liver of the child presented a massive infiltration by macrophages. Such infiltration and the segmentary albinism of the hair resemble traits of the Chediak-Higashi syndrome, but some of the most relevant traits of this syndrome are absent, since all other neutrophil functions were normal in our patient.

Adult↗
PubMedDate not supplied

[Taxonomy of the musk deer (Artiodactyla, Mammalia)].

We studied the chromosome sets and specific morphological features and phenetic traits of hair cover coloration, as well the pattern of its inheritance upon experimental hybridization. The diploid set of chromosomes in the animals from the northern part of the range contains 2n = 58 (there are two additional B-chromosomes in the Far Eastern musk deer) and is identical to that from the southern musk deer forms. Discrete polymorphic features of neck and hair cover coloration have been identified in the northern and southern musk deer, and these are used as taxonomic features. A map illustrates distribution of the established subspecies.

Animals↗
PubMedDate not supplied

Five new mutations in the Syrian hamster: furloss, fur-deficiency, juvenile gray, ashen, and quaking.

Five new mutations in the Syrian hamster are described: furloss, a simple recessive trait affecting the quality of hair; fur-deficiency, a simple recessive trait affecting the quantity of hair and longevity; juvenile gray, a simple recessive trait affecting coat color and body size; ashen, a semidominant trait affecting both coat color and quantity of hair; and quaking, a simple recessive trait affecting motor activity. Gene symbols, fs, Rfd, jg, A, and q are proposed for these mutations.

Alopecia↗
PubMed1986

Anthropological study of digital and parietal hair of Canadians.

Hair exhibits many interesting anthropologic and genetic features such as thickness and cross-sectional morphology. Digital hair, though not adequately studied to date, has potential importance as an anthropologic trait. A digital hair score system was devised in which a number of dorsally haired digital segments (nine segments) of the left fingers, excluding onychogenic segments, was used as a measure of the trait. Thickness and cross-section of the parietal hair of the Ojibwas, a tribe of Canadian Indians, and European Canadians residing in Ontario were compared with those of Japanese and Koreans residing in their respective countries. Segmental distribution of the digital hair in both males and females was similar between Ojibwas and Japanese, Koreans or Formosans, and was significantly larger in British and other European Canadians. Parietal hair of Ojibwas, both males and females, was thinner than that of Japanese, and thicker than that of British Canadians. The parietal hair index was almost equal between Ojibwas and Japanese in both sexes. That of British Canadians was significantly smaller.

Canada↗