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P Protein
P protein, also known as melanocyte-specific transporter protein or pink-eyed dilution protein homolog, is a protein that in humans is encoded by the oculocutaneous albinism II (''OCA2'') gene. The P protein is believed to be an integral membrane protein involved in small molecule transport, specifically of tyrosine—a precursor of melanin. Certain mutations in OCA2 result in type 2 oculocutaneous albinism. OCA2 encodes the human homologue of the mouse p (pink-eyed dilution) gene. The human OCA2 gene is located on the long arm (q) of chromosome 15, specifically from base pair 28,000,020 to base pair 28,344,457 on chromosome 15. Function OCA2 provides instructions for making the protein called P protein which is located in melanocytes which are specialized cells that produce melanin, and in the cells of the retinal pigment epithelium. Melanin is responsible for giving color to the skin, hair, and eyes. Moreover, melanin is found in the light-sensitive tissue of the retina of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astyanax Mexicanus
The Mexican tetra (''Astyanax mexicanus''), also known as the blind cave fish, blind cave characin or the blind cave tetra, is a freshwater fish in the Characidae family (tetras and relatives) of the order Characiformes. The type species of its genus, it is native to the Nearctic realm, originating in the lower Rio Grande, and the Neueces and Pecos Rivers in Texas, into the Central Plateau and eastern states of Mexico. Maturing at a total length of about , the Mexican tetra is of typical characin form, albeit with silvery, unremarkable scalation, likely an evolutionary adaptation to its natural environment. By comparison, the species' blind "cave" form has scales which evolved a pale, pinkish-white color, somewhat resembling an albino, as it inhabits pitch-black caverns and subterranean streams and has no need for a colorful appearance (i.e. for attracting mates). Likewise, the blind cave tetra has fully "devolved" (lost) the use of its eyes by living in an environment compl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allele
An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), but they can also have insertions and deletions of up to several thousand base pairs. Most alleles observed result in little or no change in the function or amount of the gene product(s) they code or regulate for. However, sometimes different alleles can result in different observable phenotypic traits, such as different pigmentation. A notable example of this is Gregor Mendel's discovery that the white and purple flower colors in pea plants were the result of a single gene with two alleles. Nearly all multicellular organisms have two sets of chromosomes at some point in their biological life cycle; that is, they are diploid. For a given locus, if the two chromosomes contain the same allele, they, and the organism, are homozygous with re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Color
Eye color is a polygene, polygenic phenotypic trait determined by two factors: the pigmentation of the eye's Iris (anatomy), iris and the frequency-dependence of the scattering of light by the Turbidity, turbid medium in the Stroma of iris, stroma of the iris. In humans, the pigmentation of the Iris (anatomy), iris varies from light brown to black, depending on the concentration of melanin in the iris pigment epithelium (located on the back of the iris), the melanin content within the iris stroma (located at the front of the iris), and the cellular density of the stroma. The appearance of blue, green, and hazel eyes results from the Tyndall effect, Tyndall scattering of light in the stroma, a phenomenon similar to Rayleigh scattering which accounts for the blue sky. Neither blue nor green pigments are present in the human iris or vitreous humour. This is an example of structural color, which depends on the lighting conditions, especially for lighter-colored eyes. The brightly c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HERC2
HERC2, or HECT and RLD domain containing E3 ubiquitin protein ligase 2, is a giant Ubiquitin ligase, E3 ubiquitin protein ligase, implicated in DNA repair regulation, pigmentation and neurological disorders. It is encoded by a gene of the same name belonging to the HERC family, which typically encodes large protein products with C-terminal HECT domains and one or more RCC1-like (RLD) Protein domain, domains. History HERC2, previously referred to as the ''rjs'' gene locus, was first identified in 1990 as the gene responsible for two phenotypes in mice: the runty, jerky, sterile (rjs) phenotype and the juvenile development and fertility-2 (Jdf2) phenotype. Mutant alleles are known to cause hypo-pigmentation and pink eye phenotypes, as well reduced growth, jerky gait, male sterility, female semi-sterility, and maternal behaviour defects in mice. Gene locus The full ''HERC2'' gene is located at 15q13, encoded by 93 exons and its transcription is under the control of a CpG site, C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prader–Willi Syndrome
Prader–Willi syndrome (PWS) is a rare genetic disorder caused by a loss of function of specific genes on chromosome 15. In newborns, symptoms include hypotonia, weak muscles, poor feeding, and slow development. Beginning in childhood, those affected become constantly hungry, which often leads to obesity and type 2 diabetes. Mild to moderate intellectual impairment and Behavioural problems, behavioral problems are also typical of the disorder. Often, affected individuals have a narrow forehead, small hands and feet, short height, and light skin and hair. Most are Infertility, unable to have children. About 74% of cases occur when part of the father's chromosome 15 is deleted. In another 25% of cases, the affected person has Uniparental disomy, two copies of the maternal chromosome 15 from the mother and lacks the paternal copy. As parts of the chromosome from the mother are turned off through Genomic imprinting, imprinting, they end up with no working copies of certain genes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angelman Syndrome
Angelman syndrome (AS) is a genetic disorder that affects approximately 1 in 15,000 individuals. AS impairs the function of the nervous system, producing symptoms, such as severe intellectual disability, developmental disability, limited to no functional speech, balance and movement problems, seizures, hyperactivity, and sleep problems. Physical symptoms include a small head and a specific facial appearance. Additionally, those affected usually have a happy personality and have a particular interest in water. Angelman syndrome involves genes that have also been linked to 1–2% of autism spectrum disorder cases. Epidemiology Though the prevalence of Angelman syndrome is not precisely known, there are some estimates. The best data available are from studies of school age children, ages 6–13 years, living in Sweden and from Denmark where the diagnosis of AS children in medical clinics was compared to an 8-year period of about 45,000 births. The Swedish study showed an AS preva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orphanet
Orphanet is an organisation and knowledge base dedicated to rare diseases as well as corresponding diagnosis, orphan drugs, clinical trials and expert networks. Orphanet was founded in France in 1997 by Inserm, the French National Institute of Health and Medical Research. The website is managed by a network of academic establishments from 40 countries, led by Inserm, and is a European Union Health Programme Joint Action. It contains content for both physicians and patients. Its administrative office is in Paris and its official medical journal is the '' Orphanet Journal of Rare Diseases'' published on its behalf by BioMed Central. , the site provides information on over 6,100 rare diseases and 5,400 genes. Available information Orphanet is an online database with the goal of gathering, providing and improving knowledge on rare diseases and to improve the diagnosis, care and treatment of patients with rare diseases. By listing rare diseases, and maintaining a standard nomenclatu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oculocutaneous Albinism
Oculocutaneous albinism is a form of Albinism in humans, albinism involving the human eye, eyes (''wikt:oculo-#Prefix, oculo-''), the human skin, skin (''-wikt:cutaneous#Adjective, cutaneous''), and the hair. Overall, an estimated 1 in 20,000 people worldwide are born with oculocutaneous albinism. OCA is caused by mutations in several genes that control the biosynthesis, synthesis of melanin within the melanocytes. Seven types of oculocutaneous albinism have been described, all caused by a disruption of melanin synthesis and all autosomal recessive disorders. Oculocutaneous albinism is also found in non-human animals. Types The following types of oculocutaneous albinism have been identified in humans. See also * Piebaldism * List of skin conditions * List of cutaneous conditions associated with increased risk of nonmelanoma skin cancer References External links Oculocutaneous albinism informationat RareDiseases.org NCBI Genetic Testing Registry {{DEFAULTSORT:Ocul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin ''cutis'' 'skin'). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments, and internal organs. Skin of a different nature exists in amphibians, reptiles, and birds. Skin (including cutaneous and subcutaneous tissues) plays crucial roles in formation, structure, and function of extraskeletal apparatus such as horns of bovids (e.g., cattle) and rhinos, cervids' antlers, giraffids' ossicones, armadillos' osteoderm, and os penis/ os clitoris. All mammals have some hair on their skin, even marine mammals like whales, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hair
Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellus hair. Most common interest in hair is focused on hair growth, hair types, and hair care, but hair is also an important biomaterial primarily composed of protein, notably alpha-keratin. Attitudes towards different forms of hair, such as hairstyles and hair removal, vary widely across different cultures and historical periods, but it is often used to indicate a person's personal beliefs or social position, such as their age, gender, or religion. Overview Meaning The word "hair" usually refers to two distinct structures: #the part beneath the skin, called the hair follicle, or, when pulled from the skin, the bulb or root. This organ is located in the dermis and maintains stem cells, which not only re-grow the hair afte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albinism
Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of the terms mean that written reports of albinistic animals can be difficult to verify. Albinism can reduce the survivability of an animal; for example, it has been suggested that albino alligators have an average survival span of only 24 hours due to the lack of protection from UV radiation and their lack of camouflage to avoid predators. It is a common misconception that all albino animals have characteristic pink or red eyes (resulting from the lack of pigment in the Iris (anatomy), iris allowing the blood vessels of the retina to be visible); this is not the case for some forms of albinism. Familiar albino animals include in-bred strains of laboratory animals (rats, mice and rabbits), but populations of naturally occurring albino animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
