Genetic Terms

Front 1

Codominance

Back 1

Neither of 2 alleles is dominant
Both expressed

Front 2

Variable expression

Back 2

Nature and severity of phenotype varies from 1 individual to another

Front 3

Incomplete penetrance

Back 3

Not all individuals with mutant genotype show phenotype

Front 4

Pleiotropy

Back 4

1 gene has > 1 effect on an individuals phenotype

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Imprinting

Back 5

Difference in phenotype depend on whether mutation is maternal or paternal origin

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Anticipation

Back 6

Severity of disease worsens or age of onset earlier in succeeding generations

(Huntington's_

Front 7

Loss of heterozygosity

Back 7

If patient inherits or develops mutation in a tumor suppressor gene, complementary allele must be deleted/mutation for cancer to develop

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Dominant negative

Back 8

Exerts a dominant effect
Heterozygote produces nonfunctional altered protein that also prevents the normal gene product from functioning

Front 9

Linkage disequilibrium

Back 9

Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance

Measured in population
Often varies between populations

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Mosaicisim

Back 10

Occurs when cells in body have different genetic make up

Front 11

Lyonization

Back 11

Random X inactivation in females

Front 12

Locus heterogeneity

Back 12

Mutations at different loci can produce same phenotype

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Heteroplasmy

Back 13

Presence of normal and mutation mtDNA, resulting in variable expression of mitochondrial inherited diseases

Front 14

Uniparental disomy

Back 14

Offspring receives 2 copies of chromosome from 1 parent and no copies from the other parent