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Definition: Chromosomal Abnormality from The SAGE Glossary of the Social and Behavioral Sciences

Abnormalities exist when chromosomes exhibit atypical numerical properties (i.e., there is more than or less than one pair of chromosomes) or structural properties (i.e., there is extra chromosomal material, or a fraction of the chromosome is missing). Such abnormalities can lead to conditions such as Down syndrome, mental retardation, autism, or Turner's syndrome. Although some chromosomal abnormalities are believed to be inherited, most are purely accidental and occur during the conception or gestation process.


Chromosomes, Human Anomalies, and Cytogenetic Abnormalities

From Encyclopedia of Special Education: A Reference for the Education of Children, Adolescents, and Adults with Disabilities and Other Exceptional Individuals
Chromosomal (cytogenetic) abnormalities are the most frequent cause of congenital (present at birth) malformations, affecting some 1 in 200 newborns ( Moore ,). Their importance is reflected in the fact that they account for at least 10 to 15% of individuals with mental retardation severe enough to require institutionalization ( Moore ,; Pueschel ,) and for about 8 to 10% of newborn and early infant deaths ( Sperling ,). Further, some 30% of spontaneously aborted embryos/fetuses had a chromosomal abnormality, an incidence 50 times higher than that in live births, meaning that incidence in all pregnancies must be about 5% ( Sperling ,). Because chromosomal abnormalities involve disruption in the action of many genes, most are associated with severe and varied effects ( Brown ,). These frequently, but not always, involve general and specific intellective deficits, particular facial anomalies, and cardiovascular, digestive, and pulmonary defects. Further, people with chromosomal…
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Full text Article Chromosomal abnormalities

From Cambridge Handbook of Psychology, Health and Medicine
Genetic influences on psychological functioning are well established (McGuffin et al ., 2004). A multifactorial interactional model between polygenic inheritance and environmental experience is most commonly proposed. However, many single gene anomalies have characteristic psychological profiles. …
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Full text Article Human Chromosome Aberrations

From Brenner's Encyclopedia of Genetics
Human Chromosome Aberrations
Abstract Chromosome aberrations are genetic abnormalities sufficiently large to be recognizable by chromosome analysis using a light microscope. Two main types are recognized, namely, abnormalities in number of chromosomes and abnormalities in chromosome structure. Their diagnosis usually requires…
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Full text Article Cytogenetics

From Black's Veterinary Dictionary
The study of chromosomes and the genetics of cellular constituents involved in heredity. Usually, white blood cells are used, and these are inoculated into a liquid tissue culture medium, supplemented with serum and antibiotics. Phytohaemaglutinin, a plant extract which stimulates the white cells to…
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Full text Article Human Chromosomes

From Brenner's Encyclopedia of Genetics
Human Chromosomes
Abstract Chromosomes are rod-shaped structures, visible during cell division, each composed of a DNA molecule and associated acidic and basic proteins. The complete genome of an individual is contained in the complement of chromosomes in each somatic cell. Although human chromosomes were first…
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Full text Article Stroud-Lee, Agnes Naranjo

From Encyclopedia of the American Indian in the Twentieth Century
(b. 1922–) Santa Clara Pueblo (Tewa) biologist Born on July 23, 1922, the eldest of seven children, Agnes Stroud-Lee had strong childhood interests in science, which in college led to involvement in a professor's research project testing the effects of chemicals on plant growth. Dr. Stroud-Lee…
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Voyeurism usually begins prior to age 15 and continues throughout the life span (APA, 1994). Psychoanalytic Theory. Psychoanalysts maintain that sexual deviance is the result of unresolved conflicts in psychosexual development and a regression to earlier developmental levels in an attempt to reenact…
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Full text Article restriction of cell potency

From Dictionary of Developmental Biology and Embryology
in 1936, Hans Spemann suggested a “somewhat fantastical” experiment, to transfer a nucleus from a differentiated cell into an enucleated egg. In 1952, Robert Briggs and Thomas J. King developed the techniques for the frog ( Rana ); they transferred blastula stage cell nuclei into enucleated eggs and…
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Full text Article Chromosome Banding

From Brenner's Encyclopedia of Genetics
Karyogram of a G-banded metaphase from...
Abstract Chromosome banding is a technique for staining of chromosomes so that they can be recognized and analyzed. The introduction of chromosome banding allowed thorough analysis of chromosomes across different species, and in humans, allowed recognition of the association of a wide variety of…
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Full text Article Karyotype

From Encyclopedia of Autism Spectrum Disorders
A karyotype is an organized picture of an individual’s entire set of chromosomes: 22 pairs of auto-somes (nonsex chromosomes) and 1 pair of sex chromosomes (XX or XY). Karyotypes are used in cytogenetics to identify abnormalities in the number or gross structure of an individual’s chromosomes (Jorde…
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Full text Article Melanoma, Cytogenetic Studies

From Brenner's Encyclopedia of Genetics
Melanoma, Cytogenetic Studies
Abstract Cytogenetic studies of both cutaneous malignant melanoma and intraocular uveal melanoma revealed several recurrent, nonrandom chromosome abnormalities contributing to the pathogenesis and/or progression of these diseases. These aberrations helped identify oncogenes and tumor-suppressor…
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