Acquired characteristic

Last updated

An acquired characteristic is a non-heritable change in a function or structure of a living organism caused after birth by disease, injury, accident, deliberate modification, variation, repeated use, disuse, misuse, or other environmental influence. Acquired traits are synonymous with acquired characteristics. They are not passed on to offspring through reproduction.

Contents

The changes that constitute acquired characteristics can have many manifestations and degrees of visibility, but they all have one thing in common. They change a facet of a living organism's function or structure after birth.

For example:

Acquired characteristics can be minor and temporary like bruises, blisters, or shaving body hair. Permanent but inconspicuous or invisible ones are corrective eye surgery and organ transplant or removal. Semi-permanent but inconspicuous or invisible traits are vaccination and laser hair removal. Perms, tattoos, scars, and amputations are semi-permanent and highly visible.

Applying makeup, nail polish, dying one's hair, applying henna to the skin, and tooth whitening are not examples of acquired traits. They change the appearance of a facet of an organism, but do not change the structure or functionality.

Inheritance of acquired characteristics was historically proposed by renowned theorists such as Hippocrates, Aristotle, and French naturalist Jean-Baptiste Lamarck. Conversely, this hypothesis was denounced by other renowned theorists such as Charles Darwin. Today, although Lamarckism is generally discredited, there is still debate on whether some acquired characteristics in organisms are actually inheritable. [1] [2]

Disputes

Acquired characteristics, by definition, are characteristics that are gained by an organism after birth as a result of external influences or the organism's own activities which change its structure or function and cannot be inherited. [3] [4] [5] Inherited characteristics, by definition, are characteristics that are gained or to which an organism is predisposed as a result of genetic transmission from its parents and can be passed to the organism's offspring. [6] [7] [8] Therefore, every condition an organism does not gain or develop because of inheritance of its parents' genetic information must be considered an acquired characteristic.

Eye color

It is fairly common for mammalian eyes to change color in the first years of life. This happens, with human infants and kittens being some well-known examples, because the eyes of the baby, just like the rest of its body, are still developing. This change can be as simple as blue to brown, or can involve multiple color changes in which neither the child's parents nor his/her doctors know when the changes will stop and what the final eye color will be. [9]

Changes in eye color signal changes in the arrangement and concentration of pigment in the iris, which is an example of structural color. Even though this change happens after birth, it is strictly as result of genes. While changes in eye appearance (and function, and structure) that occur because of acquired characteristics like injury, illness, old age, or malnutrition are definitely acquired characteristics, the infantile color change as described above is usually considered inherited.

Certain genetic conditions

When diseases are caused by environmental influences, such as iodine deficiency or lead poisoning, their resultant symptoms are unequivocally agreed to be acquired characteristics. However, it is debatable whether changes in bodily functions due to disorders that are partly or wholly genetic in origin are actually "acquired".

Wholly genetic disorders, such as Huntingtons, are inherited from parents' genes and are present before birth but the symptoms that develop after birth are delayed manifestations of the inherited trait.

Disorders that are partially genetic, such as ALS and allergies, mean the organism has inherited a predisposition to develop a certain condition but that inherited increased likelihood can be reduced or further increased depending on acquired characteristics of the organism.

De novo mutations

New mutations, (often somatic, spontaneous and sporadic), not inherited from either parent are called de novo mutations. [10] The consensus on whether certain prenatal spontaneous mutations and genetic disorders that occur as a result of meiotic and chromosome errors [11] or during cell division after conception, like cystic fibrosis and Down syndrome, are considered to be acquired or inherited [12] is unclear. Mutations and meiotic errors can be considered inherited since the organism is born with them in its genes, but they can also be seen as prenatal acquired characteristics since they are not actually inherited from its parents. [13] With de novo mutations and division errors, the relationship between the offspring's altered genes and gene inheritance from the parents is technically spurious. [13] These genetic errors can affect the mind as well as the body and can result in schizophrenia, [14] [15] autism, [11] bi-polar disorder, [16] and cognitive [17] disabilities.

Prenatal conditions

The definitions of inherited and acquired characteristics leave a gray area for trauma, pre-existing and gestational maternal conditions that affect the fetus, as well as chemical and pathogen exposures and trauma that happen before and while an organism is born, such as AIDS, syphilis, Hepatitis B, chickenpox, rubella, unregulated gestational diabetes, and fetal alcohol syndrome. [18] Most infections won't affect a fetus if the pregnant mother contracts it, but some can be transmitted to babies via the placenta or during birth, and others cause more severe symptoms in pregnant women or can cause complications to the pregnancy. [19]

Types

The World Health Organization defines health as "a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity." [20] Acquired characteristics do not necessarily affect the health of an organism, (a scar, suntan, or perm) but examples that do are often the first that come to mind when thinking of acquired characteristics since they are the easiest to observe and the ones that we, ourselves, are most familiar with.

Physical

Physical acquired characteristics can stem from various environmental influences such as disease, modification, injury, and regular or infrequent use of body parts.

Mental

Mental traits are acquired by learning and adapting native traits to the environment of the individual.

Sentiments are the result of the compounding of primary emotions, being "bound up with knowledge and ideas." [21] Only through vast experience in the natural world can humans learn to recognize objects in all of the various orientations in which we encounter them on a day-to-day basis. [22] The ability to do something well is an acquired characteristic, since a skill comes from one's knowledge, practice, aptitude, etc. [23]

Period of origin

There are mainly four types of disease:

Prenatal

Congenital disorders, or birth defects, are conditions present at birth. They may be structural or functional, and can result from genetic or chromosomal disorders or from environmental factors during pregnancy. Environmental factors may include exposure to chemicals, infections, or physical trauma.

Chemical exposure

Hormones are chemicals released by a cell or a gland in one part of the body that affect cells in other parts of the organism.

Chemicals are substances with distinct molecular compositions that are produced by or used in a chemical process. While all types of asbestos fibers are known to cause serious health hazards in humans, [24] [25] [26]

Maternal conditions during gestation

Worth noting is the importance of prenatal nutrition to proper mental and physical development. A correlation between fraternal birth order and male sexual orientation has been suggested to be responsible for up to 15 percent of homosexuality. [27] It is hypothesized to have something to do with changes induced in the mother's body when gestating a boy that affects subsequent sons, possibly an in-utero maternal immune response. [28] [29] [30] [31]

There is also reason to believe that the immune system of a baby will be healthier if, during pregnancy, the mother's immune system was regularly stimulated by exposure to pathogens.

"...A mother's farm exposure affects her baby's T regulatory cells. These cells, it is now believed, act to suppress immune responses and thereby maintain immune system homeostasis to contribute to healthy immune development. ... The babies of mothers exposed to farms have more and better functioning regulatory T cells."

—  [32]

Childhood

It is posited that the absence of exposure to parasites, bacteria, and viruses is playing a significant role in the development of autoimmune diseases in the more sanitized Western industrialized nations. [33] [34] Lack of exposure to naturally occurring pathogens may result in an increased incidence of autoimmune diseases. [35] [36] (See hygiene hypothesis.)

A complete explanation of how environmental factors play a role in autoimmune diseases has still not been proposed. However epidemiological studies, such as the meta analysis by Leonardi-Bee, et al., [35] have helped to establish the link between parasitic infestation and autoimmune disease development, in other words, exposure to parasites reduces incidence of an autoimmune disease developing.

"Early life exposure to microbes (i.e., germs) is an important determinant of adulthood sensitivity to allergic and autoimmune diseases such as hay fever, asthma and inflammatory bowel disease." [37]

"Immunological diseases, such as eczema and asthma, are on the increase in westernized society and represent a major challenge for 21st century medicine. ...[G]rowing up on a farm directly affects the regulation of the immune system and causes a reduction in the immunological responses to food proteins," [38] which not only means less severe reactions to food allergies, lactose intolerance, gluten sensitivity, etc., but reductions in the likelihood of developing them in the first place.

Causes

Disease

Disease is any condition that impairs the normal physical or mental (or both) function of an organism. (Though this definition includes injuries, it will not be discussed here). Diseases can arise from infection, environmental conditions, accidents, and inherited diseases.

It is not always easy to classify the source of a health problem. For instance, people can develop gout, which is known to cause permanent or near permanent changes to the human body, [39] because of diet, inherited genetic predisposition, as a secondary condition from other diseases, or as an unintended side effect of certain medications.

Infectious diseases can be caused by pathogens and microorganisms such as viruses, prions, bacteria, parasites, and fungi.

For infectious, environmental, and genetically predisposed conditions, lifestyle choices such as exercise, nutrition, stress level, hygiene, home and work environments, use or abuse of legal and illegal drugs, and access to healthcare (including an individual's financial ability and personal willingness to seek medical attention) especially in the early stages of an illness all combine to determine a person's risk factors for developing a disease or condition.

Precancerous condition Progressive disease localized disease to spread to other area of the body.

Diet

The World Food Program and UNICEF reported last year that chronic malnutrition had left 42 percent of North Korean children stunted — meaning their growth was seriously impaired, most likely permanently. An earlier report by the U.N. agencies warned that there was strong evidence that physical stunting could be accompanied by intellectual impairment.

— Demick, Barbara. 2-14-2004. The Seattle Times. [40]

"North Koreans are on average three inches shorter than their cousins in the South."

This statistic, or versions of it, have been quoted for some time. In 2010, the late Christopher Hitchens put the difference at six inches in an article in Slate , titled "A Nation of Racist Dwarfs". Martin Bloem is head of nutrition at the World Food Programme, which has been providing food aid to North Korea since 1995. He says poor diet in the early years of life leads to stunted growth. "Food and what happens in the first two years of life is actually critical for people's height later," he says.

Today, according to the World Food Programme, "one in every three children [in North Korea] remains chronically malnourished or 'stunted', meaning they are too short for their age".

— Knight, Richard. 4-22-2012. BBC News [41]

Injury

Trauma is "a body wound or shock produced by sudden physical injury, as from violence or accident," [42] or, more simply put, is "a physical wound or injury, such as a fracture or blow." [43]

Accidental injuries, most of which can be predicted and thus prevented, are the unintentional negative outcomes of unforeseen or unplanned events or circumstances which may have been avoided or prevented if reasonable measures had been taken or if the risks involving the circumstances leading up to the accident been recognized and acted upon (minimized).

Battery is a criminal offense involving the use of force against another that results in harmful or offensive contact. [44] (Assault is fear/belief of impending battery.) Violence is defined by the WHO as the intentional use of physical force or power, threatened or actual, against oneself or others that either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment or deprivation. [45]

Head trauma

Head trauma in the form of a traumatic brain injury, stroke, drug or alcohol abuse, and infection have been known in some cases to cause changes to a person's mental processes, the most common being amnesia, ability to deal with stress and changes in aggression. There have also been documented cases of a person's personality changing more drastically, the best-known case being Phineas Gage, who in 1848 who survived a 1.1 meter long tamping iron being driven through his skull (though almost all presentations of Gage's subsequent personality changes are grossly exaggerated).

There is also the rare condition called Foreign Accent Syndrome that occurs after a brain injury. The injured person will appear to speak in a new language or dialect. This is typically thought to be due to an injury to the linguistic center of the brain causing speech impairment that just happens to sound like a person's non-native language. This is thought to be the reasoning behind the urban legend where someone wakes from a coma or surgery and suddenly speaks a new language. [46]

Body modification

Body modification is the deliberate altering of the human body for any non-medical reason, such as aesthetics, sexual enhancement, a rite of passage, religious reasons, to display group membership or affiliation, to create body art, shock value, or self-expression. [47]

See also

Related Research Articles

<span class="mw-page-title-main">Disease</span> Abnormal condition that negatively affects an organism

A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies, and autoimmune disorders.

<span class="mw-page-title-main">Genetics</span> Science of genes, heredity, and variation in living organisms

Genetics is the study of genes, genetic variation, and heredity in organisms. It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene.

<span class="mw-page-title-main">Genetic disorder</span> Health problem caused by one or more abnormalities in the genome

A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development, or it can be inherited from two parents who are carriers of a faulty gene or from a parent with the disorder. When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA.

<span class="mw-page-title-main">Phenotype</span> Composite of the organisms observable characteristics or traits

In genetics, the phenotype is the set of observable characteristics or traits of an organism. The term covers the organism's morphology, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code and the influence of environmental factors. Both factors may interact, further affecting the phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book The Extended Phenotype suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams as "extended phenotypes".

Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affect the patient's immune system. Examples of these extrinsic factors include HIV infection and environmental factors, such as nutrition. Immunocompromisation may also be due to genetic diseases/flaws such as SCID.

<span class="mw-page-title-main">Hashimoto's thyroiditis</span> Autoimmune disease

Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis and Hashimoto's disease, is an autoimmune disease in which the thyroid gland is gradually destroyed. Early on, symptoms may not be noticed. Over time, the thyroid may enlarge, forming a painless goiter. Some people eventually develop hypothyroidism with accompanying weight gain, fatigue, constipation, depression, hair loss, and general pains. After many years the thyroid typically shrinks in size. Potential complications include thyroid lymphoma. Furthermore, because it is common for untreated patients of Hashimoto's to develop hypothyroidism, further complications can include, but are not limited to, high cholesterol, heart disease, heart failure, high blood pressure, myxedema, and potential pregnancy problems.

The term modifications in genetics refers to both naturally occurring and engineered changes in DNA. Incidental, or natural mutations occur through errors during replication and repair, either spontaneously or due to environmental stressors. Intentional modifications are done in a laboratory for various purposes, developing hardier seeds and plants, and increasingly to treat human disease. The use of gene editing technology remains controversial.

<span class="mw-page-title-main">Pleiotropy</span> Influence of a single gene on multiple phenotypic traits

Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. Such a gene that exhibits multiple phenotypic expression is called a pleiotropic gene. Mutation in a pleiotropic gene may have an effect on several traits simultaneously, due to the gene coding for a product used by a myriad of cells or different targets that have the same signaling function.

<span class="mw-page-title-main">Human genetics</span> Study of inheritance as it occurs in human beings

Human genetics is the study of inheritance as it occurs in human beings. Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics, and genetic counseling.

A connective tissue disease (collagenosis) is any disease that has the connective tissues of the body as a target of pathology. Connective tissue is any type of biological tissue with an extensive extracellular matrix that supports, binds together, and protects organs. These tissues form a framework, or matrix, for the body, and are composed of two major structural protein molecules: collagen and elastin. There are many different types of collagen protein in each of the body's tissues. Elastin has the capability of stretching and returning to its original length—like a spring or rubber band. Elastin is the major component of ligaments and skin. In patients with connective tissue disease, it is common for collagen and elastin to become injured by inflammation (ICT). Many connective tissue diseases feature abnormal immune system activity with inflammation in tissues as a result of an immune system that is directed against one's own body tissues (autoimmunity).

Neurodevelopmental disorders are a group of neurological disorders that affect the development of the nervous system, leading to abnormal brain function which may affect emotion, learning ability, self-control, and memory. The effects of neurodevelopmental disorders tend to last for a person's lifetime.

<span class="mw-page-title-main">Causes of autism</span> Proposed causes of autism

The causes of autism are environmental or genetic factors that predispose an individual to develop autism, also known as autism spectrum disorder (ASD). Many causes of autism have been proposed, but understanding of the theory of causation of autism is incomplete. Attempts have been made to incorporate the known genetic and environmental causes into a comprehensive causative framework. ASD is a neurodevelopmental disorder marked by impairments in communicative ability and social interaction and restricted/repetitive behaviors, interests, or activities not suitable for the individual's developmental stage. The severity of symptoms and functional impairment vary between individuals.

Immune dysregulation is any proposed or confirmed breakdown or maladaptive change in molecular control of immune system processes. For example, dysregulation is a component in the pathogenesis of autoimmune diseases and some cancers. Immune system dysfunction, as seen in IPEX syndrome leads to immune dysfunction, polyendocrinopathy, enteropathy, X-linked (IPEX). IPEX typically presents during the first few months of life with diabetes mellitus, intractable diarrhea, failure to thrive, eczema, and hemolytic anemia. unrestrained or unregulated immune response.

Immunogenetics or immungenetics is the branch of Medical Immunology and Medical Genetics that explores the relationship between the immune system and genetics.

An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways:

<span class="mw-page-title-main">Central nervous system disease</span> Disease of the brain or spinal cord

Central nervous system diseases, also known as central nervous system disorders, are a group of neurological disorders that affect the structure or function of the brain or spinal cord, which collectively form the central nervous system (CNS). These disorders may be caused by such things as infection, injury, blood clots, age related degeneration, cancer, autoimmune disfunction, and birth defects. The symptoms vary widely, as do the treatments.

<span class="mw-page-title-main">Neurogenetics</span>

Neurogenetics studies the role of genetics in the development and function of the nervous system. It considers neural characteristics as phenotypes, and is mainly based on the observation that the nervous systems of individuals, even of those belonging to the same species, may not be identical. As the name implies, it draws aspects from both the studies of neuroscience and genetics, focusing in particular how the genetic code an organism carries affects its expressed traits. Mutations in this genetic sequence can have a wide range of effects on the quality of life of the individual. Neurological diseases, behavior and personality are all studied in the context of neurogenetics. The field of neurogenetics emerged in the mid to late 20th century with advances closely following advancements made in available technology. Currently, neurogenetics is the center of much research utilizing cutting edge techniques.

<span class="mw-page-title-main">Autoimmune disease</span> Abnormal immune response to a normal body part

An autoimmune disease is a condition that results from an anomalous response of the immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved.

The evolution of schizophrenia refers to the theory of natural selection working in favor of selecting traits that are characteristic of the disorder. Positive symptoms are features that are not present in healthy individuals but appear as a result of the disease process. These include visual and/or auditory hallucinations, delusions, paranoia, and major thought disorders. Negative symptoms refer to features that are normally present but are reduced or absent as a result of the disease process, including social withdrawal, apathy, anhedonia, alogia, and behavioral perseveration. Cognitive symptoms of schizophrenia involve disturbances in executive functions, working memory impairment, and inability to sustain attention.

The development of an animal model of autism is one approach researchers use to study potential causes of autism. Given the complexity of autism and its etiology, researchers often focus only on single features of autism when using animal models.

References

  1. ↑ Kofoid, C. A. (June 1925). "The Inheritance of Acquired Characteristics". Am J Public Health. 15 (6): 549. doi:10.2105/ajph.15.6.549-a. PMC   1320859 .
  2. ↑ Nisbet-Brown, E.; Wegmann, T. G. (1981). "Is acquired immunological tolerance genetically transmissible?". Proceedings of the National Academy of Sciences of the United States of America. 78 (9): 5826–5828. Bibcode:1981PNAS...78.5826N. doi: 10.1073/pnas.78.9.5826 . PMC   348875 . PMID   7029546.
  3. ↑ "Acquired characteristic - definition of acquired characteristic by The Free Dictionary". Thefreedictionary.com. Retrieved 2015-08-27.
  4. ↑ "Acquired characteristic | Define Acquired characteristic at Dictionary.com". Dictionary.reference.com. Retrieved 2015-08-27.
  5. ↑ "Acquired characteristics | definition of Acquired characteristics by Medical dictionary". Medical-dictionary.thefreedictionary.com. Retrieved 2015-08-27.
  6. ↑ "Inherited trait - definition of Inherited trait by The Free Dictionary". Thefreedictionary.com. Retrieved 2015-08-27.
  7. ↑ "Inherited character | Define Inherited character at Dictionary.com". Dictionary.reference.com. Retrieved 2015-08-27.
  8. ↑ "Inherited trait | definition of inherited trait by Medical dictionary". Medical-dictionary.thefreedictionary.com. Retrieved 2015-08-27.
  9. ↑ "Baby's Eye Color". What To Expect. Retrieved 2015-08-27.
  10. ↑ Zhao, Xiaoyue; Leotta, Anthony; Kustanovich, Vlad; Lajonchere, Clara; Geschwind, Daniel H.; Law, Kiely; Law, Paul; Qiu, Shanping; Lord, Catherine; Sebat, Jonathan; Ye, Kenny; Wigler, Michael (2007). "A unified genetic theory for sporadic and inherited autism". Proceedings of the National Academy of Sciences. 104 (31): 12831–6. Bibcode:2007PNAS..10412831Z. doi: 10.1073/pnas.0705803104 . JSTOR   25436390. PMC   1933261 . PMID   17652511.
  11. 1 2 "New Genetic Risk Factor for Both Autism and Schizophrenia". ScienceDaily. November 4, 2010. Retrieved May 17, 2012. Researchers have uncovered a prominent genetic risk factor for autism spectrum disorders and schizophrenia. The study reports a small genomic deletion in patients with these neurological conditions. ...
  12. ↑ "Mutations Not Inherited from Parents Cause More Than Half the Cases of Schizophrenia". ScienceDaily. August 7, 2011. Retrieved May 17, 2012.
  13. 1 2 "New Model For Autism Suggests Women Carry The Disorder And Explains Age As A Risk Factor". ScienceDaily. July 24, 2007. Retrieved May 17, 2012. Spontaneous mutations are changes in a chromosome that alter genes. Germ-line mutations are newly acquired in a germ cell of a parent, and sometimes are transmitted to offspring at conception. ... "The fact that germ-line mutations increase with age places older parents at a higher risk of having children with autism..." said CSHL co-author of the study [Dr.] Michael Wigler. ... Wigler suggests that "what we now know about spontaneous mutations and autism offers an alternative to traditional thinking about genetic disorders as purely heritable from a parent.
  14. ↑ "New genetic clues for schizophrenia; De novo mutations more frequent, study finds". ScienceDaily. July 11, 2011. Retrieved 2015-08-27.
  15. ↑ "Gene Mutations Responsible For 10 Percent Of Schizophrenia Pinpointed". ScienceDaily. June 1, 2008. Retrieved 2015-08-27.
  16. ↑ "Rare genetic mutations linked to bipolar disorder". ScienceDaily. 2012-01-13. Retrieved 2015-08-27.
  17. ↑ "Intellectual disability is frequently caused by non-hereditary genetic problems, study finds". ScienceDaily. 2011-04-25. Retrieved 2015-08-27.
  18. ↑ Archived May 1, 2012, at the Wayback Machine
  19. ↑ "Infections that can affect pregnancy". BabyCenter. Retrieved 2015-08-27.
  20. ↑ "Constitution". www.who.int. World Health Organization. Archived from the original on March 17, 2019.
  21. ↑ Woodworth, Robert S (1921). Psychology: A Study of Mental Life. New York: Henry Holt and Company. p. i. Retrieved 2015-08-27.
  22. ↑ "Neuroscientists reveal how the brain learns to recognize objects". ScienceDaily. September 22, 2010. Archived from the original on April 18, 2012.
  23. ↑ "Skill | Define Skill at Dictionary.com". Dictionary.reference.com. Retrieved 2015-08-27.
  24. ↑ "WHO | Asbestos: elimination of asbestos-related diseases". Who.int. Retrieved 2015-08-27.
  25. ↑ "International Agency for Research on Cancer (IARC) Special Report, 2009 as published in The Lancet Oncology, May, 2009" (PDF). Asbestosdiseaseawareness.org. Retrieved 2015-08-27.
  26. ↑ "Collegium Razmzzini 2010 Statement on Asbestos" (PDF). Collegiumramazzini.org. Retrieved 2015-08-27.
  27. ↑ Valenzuela, Carlos Y (2010). "Sexual Orientation, Handedness, Sex Ratio, and Fetomaternal Tolerance-Rejection". Biological Research. 43 (3): 347–356. doi: 10.4067/S0716-97602010000300012 . PMID   21249307.
  28. ↑ Blanchard R (September 2001). "Fraternal birth order and the maternal immune hypothesis of male homosexuality". Horm Behav. 40 (2): 105–14. doi:10.1006/hbeh.2001.1681. PMID   11534970. S2CID   33261960.
  29. ↑ Blanchard R, Klassen P (April 1997). "H-Y antigen and homosexuality in men". J. Theor. Biol. 185 (3): 373–8. Bibcode:1997JThBi.185..373B. CiteSeerX   10.1.1.602.8423 . doi:10.1006/jtbi.1996.0315. PMID   9156085.
  30. ↑ Blanchard R, Bogaert AF (January 1996). "Homosexuality in men and number of older brothers". Am J Psychiatry. 153 (1): 27–31. doi:10.1176/ajp.153.1.27. PMID   8540587.
  31. ↑ Blanchard R (September 2004). "Quantitative and theoretical analyses of the relation between older brothers and homosexuality in men". J. Theor. Biol. 230 (2): 173–87. Bibcode:2004JThBi.230..173B. doi:10.1016/j.jtbi.2004.04.021. PMID   15302549.
  32. ↑ "Farm Moms May Help Children Beat Allergies". ScienceDaily. May 20, 2008. Archived from the original on February 12, 2012. Retrieved May 18, 2012.
  33. ↑ David E. Elliott; Robert W. Summers; Joel V. Weinstock. (2005). "Helminths and the Modulation of Mucosal Inflammation". Current Opinion in Gastroenterology. 21 (2): 51–58. PMID   15687885.
  34. ↑ Mohan C. (2006). "Environment versus genetics in autoimmunity: a geneticist's perspective". Lupus. 15 (11): 791–793. doi:10.1177/0961203306070005. PMID   17153852. S2CID   1580767.
  35. 1 2 Leonardi-Bee, J.; Pritchard, D.; Britton, J. (2006). "Asthma and current intestinal parasite infection: systematic review and meta-analysis". American Journal of Respiratory and Critical Care Medicine. 174 (5): 514–523. doi:10.1164/rccm.200603-331OC. PMID   16778161.
  36. ↑ Strachan D P. (2006). "Hay fever, hygiene, and household size". BMJ. 299 (6710): 1259–1260. doi:10.1136/bmj.299.6710.1259. PMC   1838109 . PMID   2513902.
  37. ↑ "Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis". ScienceDaily. March 22, 2012. Archived from the original on May 29, 2012.
  38. ↑ "Growing up on a farm directly affects regulation of the immune system, study finds". ScienceDaily. February 8, 2012. Archived from the original on May 13, 2012.
  39. ↑ MedlinePlus Encyclopedia : Hypothyroidism
  40. ↑ Demick, Barbara (2004-02-14). "Nation & World | Effects of famine: Short stature evident in North Korean generation | Seattle Times Newspaper". Community.seattletimes.nwsource.com. Retrieved 2015-08-27.
  41. ↑ Kerry Brown (2012-04-23). "Are North Koreans really three inches shorter than South Koreans? - BBC News". M.bbc.co.uk. Retrieved 2015-08-27.
  42. ↑ "Trauma". Dictionary.com. Dictionary.com. 2010. Retrieved 2010-10-31.
  43. ↑ Elizabeth Martin, ed. (2010). Concise Medical Dictionary (8th ed.). Market House Books.
  44. ↑ Black's Law Dictionary Garner, p. 162
  45. ↑ "WHO | World report on violence and health". Who.int. 2002-10-03. Retrieved 2015-08-27.
  46. ↑ "A Curious Case Of Foreign Accent Syndrome : Shots - Health News". NPR. 2011-06-01. Retrieved 2015-08-27.
  47. ↑ "What Is Body Modification?". Essortment.com. 1986-05-16. Archived from the original on 2016-01-28. Retrieved 2015-08-27.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.