|
EDAR
Ectodysplasin A receptor (EDAR) is a protein that in humans is encoded by the ''EDAR'' gene. EDAR is a cell surface receptor for ectodysplasin A which plays an important role in the development of ectodermal tissues such as the skin. It is structurally related to members of the TNF receptor superfamily. Function ''EDAR'' and other genes provide instructions for making proteins that work together during embryonic development. These proteins form part of a signaling pathway that is critical for the interaction between two cell layers, the ectoderm and the mesoderm. In the early embryo, these cell layers form the basis for many of the body's organs and tissues. Ectoderm-mesoderm interactions are essential for the proper formation of several structures that arise from the ectoderm, including the skin, hair, nails, teeth, and sweat glands. Clinical significance Mutation in this gene have been associated with hypohidrotic ectodermal dysplasia, a disorder characterized by a lower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypohidrotic Ectodermal Dysplasia
Hypohidrotic ectodermal dysplasia is one of about 150 types of ectodermal dysplasia in humans. These disorders result in the development of structures including the skin where people sweat less.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. . Presentation Most people with hypohidrotic ectodermal dysplasia have a reduced ability to sweat ( hypohidrosis) because they have fewer sweat glands than normal or their sweat glands do not function properly. Sweating is a major way that the body controls its temperature; as sweat evaporates from the skin, it cools the body. The hair is often light-coloured, brittle, and slow-growing. This condition is also characterized by absent teeth ( hypodontia) or teeth that are malformed. Hypohidrotic ectodermal dysplasia is the most common form of ectodermal dysplasia in humans. It is estimated to affect at least 1 in 17,000 people worldwide. Genetics Mutations in the '' EDA'', '' EDAR'', an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shovel-shaped Incisors
Shovel-shaped incisors (or, more simply, shovel incisors) are incisors whose Glossary of dentistry, lingual surfaces are scooped as a consequence of lingual marginal ridges, Crown (tooth), crown curvature, or Basal (anatomy), basal Tubercle (anatomy), tubercles, either alone or in combination. Shovel-shaped incisors are significantly common in Indigenous peoples of the Americas, Amerindians from North America, North, Central America, Central, and South America. They are also common in East Asians and Central Asians, Inuit, and Aleut peoples of Siberian Yupik, Northeast Asia and North America (including but not limited to Inuit in eastern Alaska, Northern Canada, Arctic Canada, and Greenland). In certain European peoples, European and Demographics of Africa, African groups, shovel-shaped upper incisors are uncommon or not present. There is a spectrum of the degree of shoveled-ness, ranging on a scale from 0 to 7 of spatulate incisors to shoveled incisors. It was theorized that pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TNF Receptor
The tumor necrosis factor receptor superfamily (TNFRSF) is a protein superfamily of cytokine receptors characterized by the ability to bind tumor necrosis factors (TNFs) via an extracellular cysteine-rich domain. With the exception of nerve growth factor (NGF), all TNFs are homologous to the archetypal TNF-alpha. In their active form, the majority of TNF receptors form trimeric complexes in the plasma membrane. Accordingly, most TNF receptors contain transmembrane domains (TMDs), although some can be cleaved into soluble forms (e.g. TNFR1), and some lack a TMD entirely (e.g. DcR3). In addition, most TNF receptors require specific adaptor protein such as TRADD, TRAF, RIP and FADD for downstream signalling. TNF receptors are primarily involved in apoptosis and inflammation, but they can also take part in other signal transduction pathways, such as proliferation, survival, and differentiation. TNF receptors are expressed in a wide variety of tissues in mammals, especially in leuko ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectodysplasin A
Ectodysplasin A (EDA) is a protein that in humans is encoded by the EDA gene. Ectodysplasin A is a transmembrane protein of the TNF family which plays an important role in the development of ectodermal tissues such as skin in humans. It is recognized by the ectodysplasin A receptor. Function The protein encoded by this gene is a type II membrane protein that can be cleaved by furin to produce a secreted form. The encoded protein, which belongs to the tumor necrosis factor family, acts as a homotrimer and may be involved in cell-cell signaling during the development of ectodermal organs. Along with c-Met, it has been shown to be involved in the differentiation of anatomical placodes, precursors of scales, feathers and hair follicles in vertebrates. Defects in this gene are a cause of ectodermal dysplasia, anhidrotic, which is also known as X-linked hypohidrotic ectodermal dysplasia. Several transcript variants encoding many different isoforms A protein isoform, or "prote ... [...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] |
Mammary Gland
A mammary gland is an exocrine gland that produces milk in humans and other mammals. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primates (for example, humans and chimpanzees), the udder in ruminants (for example, cows, goats, sheep, and deer), and the dugs of other animals (for example, dogs and cats) to feed young offspring. Lactorrhea, the occasional production of milk by the glands, can occur in any mammal, but in most mammals, lactation, the production of enough milk for nursing, occurs only in phenotypic females who have gestated in recent months or years. It is directed by hormonal guidance from sex steroids. In a few mammalian species, male lactation can occur. With humans, male lactation can occur only under specific circumstances. Mammals are divided into 3 groups: monotremes, metatherians, and eutherians. In the case of monotremes, their mammary glands are modified seba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Northern East Asian
In archaeogenetics, the term Ancient Northern East Asian (ANEA), also known as Northern East Asian (NEA), is used to summarize the related ancestral components that represent the Ancient Northern East Asian peoples, extending from the Baikal region to the Yellow River and the Qinling-Huaihe Line in present-day central China. They are inferred to have diverged from Ancient Southern East Asians (ASEA) around 20,000 to 26,000 BCE. The ANEA can be differentiated into broadly three sub-groups, namely the “Ancient Northeast Asians“ (ANA), “Neo-Siberians", and "Yellow River farmers". The ANEA are to be distinguished from the derived and namely similar "Ancient Northeast Asian" (ANA) lineage, which is alternatively also known as "Amur ancestry", and which forms a sub-group of the ANEA grouping, specifically ancestral to hunter-gatherer people of the 7th-4th millennia before present, in the Amur region and later expanding to far-eastern Siberia, Mongolia and the Baikal regions, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Last Glacial Maximum
The Last Glacial Maximum (LGM), also referred to as the Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent between 26,000 and 20,000 years ago. Ice sheets covered much of Northern North America, Northern Europe, and Asia and profoundly affected Earth's climate by causing a major expansion of deserts, along with a large drop in sea levels. Based on changes in position of ice sheet margins dated via cosmogenic nuclide, terrestrial cosmogenic nuclides and radiocarbon dating, growth of ice sheets in the southern hemisphere commenced 33,000 years ago and maximum coverage has been estimated to have occurred sometime between 26,500 years ago and 20,000 years ago. After this, deglaciation caused an abrupt rise in sea level. Decline of the West Antarctica ice sheet occurred between 14,000 and 15,000 years ago, consistent with evidence for another abrupt rise in the sea level about 14,500 years ago. Glacier fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tianyuan Man
Tianyuan man ( zh, t=田園洞人, s=田园洞人, p=Tiányuándòng Rén) are the remains of one of the earliest modern humans to inhabit East Asia. In 2007, researchers found 34 bone fragments belonging to a single individual at the Tianyuan Cave near Beijing, China. Radiocarbon dating shows the bones to be between 42,000 and 39,000 years old, which may be slightly younger than the only other finds of bones of a similar age at the Niah Caves in Sarawak on the South-east Asian island of Borneo. Subsistence Nothing is known directly about the material culture of this individual, since so far no artifacts or other cultural remains have been found at the site. Isotope analysis suggests that a substantial part of his diet came from freshwater fish. Physical anthropology Morphology Tianyuan man is considered an early modern homo sapiens. He lacks several mandibular features common among western Eurasian late archaic humans, showing its divergence. Based on the rate of dental occlu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beringia
Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 70th parallel north, 72° north latitude in the Chukchi Sea; and on the south by the tip of the Kamchatka Peninsula. It includes the Chukchi Sea, the Bering Sea, the Bering Strait, the Chukchi Peninsula, Chukchi and Kamchatka peninsulas in Russia as well as Alaska in the United States and Yukon in Canada. The area includes land lying on the North American Plate and Siberian land east of the Chersky Range. At various times, it formed a land bridge referred to as the Bering land bridge, that was up to wide at its greatest extent and which covered an area as large as British Columbia and Alberta together, totaling about , allowing biological dispersal to occur between Asia and North America. Today, the only land that is visible from the central part of the Bering land bridge are the Diomede Islands, the Pribilof Isla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and greenhouse periods during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed '' glacial periods'' (''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called '' interglacials'' or ''interstadials''. In glaciology, the term ''ice age'' is defined by the presence of extensive ice sheets in the northern and southern hemispheres. By this definition, the current Holocene epoch is an interglacial period of an ice age. The accumulation of anthropogenic greenhouse gases is projected to delay the next glacial period. History of research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethnic Groups In Europe
Europeans are the focus of European ethnology, the field of anthropology related to the various ethnic groups that reside in the List of sovereign states and dependent territories in Europe, states of Europe. Groups may be defined by common ancestry, language, faith, historical continuity, etc. There are no universally accepted and precise definitions of the terms "ethnic group" and "nationality", but in the context of European ethnography in particular, the terms ''ethnic group'', ''people'', ''nationality'' and ''ethno-linguistic group'' are used as mostly synonymous. Preference may vary in usage with respect to the situation specific to the individual countries of Europe, and the context in which they may be classified by those terms. The total number of national minority populations in Europe is estimated at 105 million people, or 14% of 770 million Europeans in 2002.Christoph Pan, Beate Sibylle Pfeil (2002), Minderheitenrechte in Europa. Handbuch der europäischen Volksgrupp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
