|
Lighter Skin
Light skin is a human skin color that has a base level of eumelanin pigmentation that has adapted to environments of low UV radiation. Light skin is most commonly found amongst the native populations of Europe and East Asia as measured through skin reflectance. People with light skin pigmentation are often referred to as "white" or "fair", although these usages can be ambiguous in some countries where they are used to refer specifically to certain ethnic groups or populations. As populations migrated away from the tropics into areas of low UV radiation, they developed light skin pigmentation as an evolutionary selection acting against vitamin D depletion. Humans with light skin pigmentation have skin with low amounts of eumelanin, and possess fewer melanosomes than humans with dark skin pigmentation. Light skin provides better absorption qualities of ultraviolet radiation. This helps the body to synthesize higher amounts of vitamin D for bodily processes such as calcium developm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birth Defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many are believed to involve multiple factors. Birth defects may be visi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (European part of Turkey), Egypt, Iran, the Levant (including Syria (region), Ash-Shām and Cyprus), Mesopotamia (modern-day Iraq), and the Socotra Governorate, Socotra Archipelago (a part of Yemen). The term came into widespread usage as a replacement of the term Near East (as opposed to the Far East) beginning in the early 20th century. The term "Middle East" has led to some confusion over its changing definitions, and has been viewed by some to be discriminatory or too Eurocentrism, Eurocentric. The region includes the vast majority of the territories included in the closely associated definition of Western Asia (including Iran), but without the South Caucasus, and additionally includes all of Egypt (not just the Sina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selective Pressure
Any cause that reduces or increases reproductive success in a portion of a population potentially exerts evolutionary pressure, selective pressure or selection pressure, driving natural selection. It is a quantitative description of the amount of change occurring in processes investigated by evolutionary biology, but the formal concept is often extended to other areas of research. In population genetics, selective pressure is usually expressed as a selection coefficient. Amino acids selective pressure It has been shown that putting an amino acid bio-synthesizing gene like ''HIS4'' gene under amino acid selective pressure in yeast causes enhancement of expression of adjacent genes which is due to the transcriptional co-regulation of two adjacent genes in Eukaryota. Antibiotic resistance Drug resistance in bacteria is an example of an outcome of natural selection. When a drug is used on a species of bacteria, those that cannot resist die and do not produce offspring, while tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin D3
Cholecalciferol, also known as vitamin D3 and colecalciferol, is a type of vitamin D that is made by the skin when exposed to sunlight; it is found in some foods and can be taken as a dietary supplement. Cholecalciferol is made in the skin following UVB light exposure. It is converted in the liver to calcifediol (25-hydroxyvitamin D) which is then converted in the kidney to calcitriol (1,25-dihydroxyvitamin D). One of its actions is to increase calcium uptake by the intestines. It is found in food such as some fish, beef liver, eggs, and cheese. Plant and cow milk, fruit juice, yogurt, and margarine also may have cholecalciferol added to them in some countries, including the United States. Cholecalciferol can be taken as an oral dietary supplement to prevent vitamin D deficiency or as a medication to treat associated diseases, including rickets. It is also used for familial hypophosphatemia, hypoparathyroidism that is causing low blood calcium, and Fanconi syndrome. Vitam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Dispersal
In the context of the recent African origin of modern humans, the Southern Dispersal scenario (also the coastal migration or great coastal migration hypothesis) refers to the early migration along the southern coast of Asia, from the Arabian Peninsula via Persia and India to Southeast Asia and Oceania. Alternative names include the "southern coastal route" or "rapid coastal settlement", with later descendants of those migrations eventually colonizing the rest of Eurasia, the remainder of Oceania, and the Americas. The coastal route theory is primarily used to describe the initial peopling of West Asia, India, Southeast Asia, New Guinea, Australia, Near Oceania, and East Asia beginning between roughly 70,000 and 50,000 years ago. It is linked with the presence and dispersal of mtDNA haplogroup M and haplogroup N, as well as the specific distribution patterns of Y-DNA haplogroup F (ancestral to O, N, R, Q), haplogroup C and haplogroup D, in these regions. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Reviews In Clinical Laboratory Sciences
''Critical Reviews in Clinical Laboratory Sciences'' is a peer-reviewed medical journal that publishes review articles on all aspects of clinical laboratory sciences on an invitation-only basis. The journal is published by Taylor and Francis and the editor-in-chief is Khosrow Adeli (University of Toronto). According to the ''Journal Citation Reports'', the journal has a 2019 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 4.677. References External links * Publications established in 1970 English-language journals Taylor & Francis academic journals Laboratory medicine journals Review journals {{med-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Clinical Nutrition
''The American Journal of Clinical Nutrition'' (''AJCN'') is a monthly peer-reviewed biomedical journal in the fields of dietetics and clinical nutrition. The journal was established in 1952 as the ''Journal of Clinical Nutrition'', edited by S.O. Waife and published by the Nutrition Press. It was continued in series under the present title from 1954 and was published by the American Society for Clinical Nutrition (ASCN).Catalog entry at the . It is now published by the .< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Folate Deficiency
Folate deficiency, also known as vitamin B9 deficiency, is a low level of folate and derivatives in the body. Signs of folate deficiency are often subtle. A low number of red blood cells (anemia) is a late finding in folate deficiency and folate deficiency anemia is the term given for this medical condition. It is characterized by the appearance of large-sized, abnormal red blood cells (megaloblasts), which form when there are inadequate stores of folic acid within the body. Signs and symptoms Loss of appetite and weight loss can occur. Additional signs are weakness, sore tongue, headaches, heart palpitations, irritability, and behavioral disorders. In adults, anemia (macrocytic, megaloblastic anemia) can be a sign of advanced folate deficiency. Women with folate deficiency who become pregnant are more likely to give birth to low birth weight premature infants, and infants with neural tube defects and even spina bifida. In infants and children, folate deficiency can lead to f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UV Radiation
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. For h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Skin
Dark skin is a type of human skin color that is rich in melanin pigments. People with very dark skin are often referred to as "black people", although this usage can be ambiguous in some countries where it is also used to specifically refer to different ethnic groups or populations. The evolution of dark skin is believed to have begun around 1.2 million years ago, in light-skinned early hominid species after they moved from the equatorial rainforest to the sunny savannas. In the heat of the savannas, better cooling mechanisms were required, which were achieved through the loss of body hair and development of more efficient perspiration. The loss of body hair led to the development of dark skin pigmentation, which acted as a mechanism of natural selection against folate (vitamin B9) depletion, and to a lesser extent, DNA damage. The primary factor contributing to the evolution of dark skin pigmentation was the breakdown of folate in reaction to ultraviolet radiation; the rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeogenetic Analysis Of Human Skin Pigmentation In Europe
Archaeogenetics is the study of ancient DNA using various molecular genetic methods and DNA resources. This form of genetic analysis can be applied to human, animal, and plant specimens. Ancient DNA can be extracted from various fossilized specimens including bones, eggshells, and artificially preserved tissues in human and animal specimens. In plants, Ancient DNA can be extracted from seeds and tissue. Archaeogenetics provides us with genetic evidence of ancient population group migrations, domestication events, and plant and animal evolution. The ancient DNA cross referenced with the DNA of relative modern genetic populations allows researchers to run comparison studies that provide a more complete analysis when ancient DNA is compromised. Archaeogenetics receives its name from the Greek word ''arkhaios'', meaning "ancient", and the term ''genetics'', meaning "the study of heredity". The term archaeogenetics was conceived by archaeologist Colin Renfrew. In February 2021, scientis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Middle East")
-cropped.jpg "Click for more on -> Dark Skin")