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23 Cards in this Set
- Front
- Back
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cytogenetics
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the field that involves the microscopic examination of chromosomes. Allowing the detection of individual with abnormal chromosomes number or structure.
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What are the main features that are used to identify chromosomes?
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The size, location of the centromere, banding patters.
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What two basic ways does chromosome variation occur?
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in structure and number
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The study of chromosome variation is important for what reasons?
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They can have a mjor effect on the phenotype of an organism, and the offspring, and is an important force in the evolution of species.
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Masaicism
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the presence of two or more cell lines in an individual, one or more of which are abnormal
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Euploidy
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changes in the entire set of chromosomes, and it occurs ocassionally in animals and frequently in plants
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Aneuploidy
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changes in individual chromosomes rather than in the complete set, regarded as abnormal conditions
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Monosomy
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one homologue is missing
2n-1 |
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Trisomy
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one extra homologue is present
2n+1 |
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tetrasomy
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Two extra homologue are present
2n+2 |
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Double monosomy
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Two different homologue are missing
2n-1-1 |
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Double trisomy
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two different extra homologue are present
2n+1+1 |
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Nullisomy
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a whole pair of chromosomes is missing
2n-2 |
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Haplo-IV in flies
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are monosomic and they are weaker and smaller
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Turner syndrome(Monosomy)
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There is only one X present(they Y or the other X is missing)
45,X or 45,XO 45-50% are mosaics 46,XX/45,XO |
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Down syndrome(trisomy)
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There is an extra 21 chromosome
46,XX or XY, +21 |
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Triplo IV in flies
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have no visible abnormalities
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Edwards syndrome(trisomy)
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there is an extra 18 chromosome
46, XX or XY, +18 10% are mosaics |
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Patau syndrome(trisomy)
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has an extra 13 chromosome
47, XX or XY, +13 |
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Klinefelter syndrome(trisomy)
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there are extra sex chromosomes
47,XXY 10% are mosaics *the more extra sex chromosomes the worst the syndrome is * |
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47, XXX syndrome
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The more X the more deadly the syndrome. Usually benign consequences, under developed of genetalia, mental retardation
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Tetra-X and penta X karyotes
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are more severe than the 47 XXX syndrome
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47, XYY condition
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above average height
sub-average intelligence |
