Genetic Terms From First Aid 2011

Front 1

Neither of 2 alleles is dominant

Back 1

codominance

Hint 1

blood types

Front 2

Nature and severity of phenotype vary from 1 individual to another

Back 2

variable expression

Hint 2

2 patients with neurofibromatosis 1 have varying disease severity

Front 3

Not all individuals with mutant genotype show mutant phenotype

Back 3

incomplete penetrance

Hint 3

--

Front 4

1 gene has more than one effect on individual's phenotype

Back 4

pleiotropy

Hint 4

PKU causes seemingly unrelated symptoms--mental retardation, hair/skin changes

Front 5

differences in phenotype depend on whetehr the mutation is of maternal or paternal origin

Back 5

imprinting

Hint 5

Prader-Willi and Angelman's syndromes

Front 6

severity of disease worsens or age of onset of disease is earlier in succeeding generations

Back 6

anticipation

Hint 6

Huntington's

Front 7

If a patient inherits or develops a mutation in a tumor suppressor gene, the complementary allele must be deleted/muateted before cancer develops. (This is not true of oncogenes--ONcogenes ONe allele

Back 7

Loss of heterozygosity

Hint 7

Retinoblastoma

Front 8

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

Back 8

Dominant negative mutation

Hint 8

Mutation of Tx factor in its allosteric site. Nonfunctioning mutant can still bind DNA, preventing wild-type Tx factor from binding.

Front 9

Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance. Measured in a population , not a family,and often varies in different populations.

Back 9

Linkage disequilibrium

Hint 9

--

Front 10

Occurs when cells in the body have different genetic makeup.
Can be a germ-line, which may produce disease that is not carried by parent's somatic cells.

Back 10

Mosaicism

Hint 10

Lyonization-random X inactivation in females.

Front 11

Mutations at different loci can produce the same phenotype.

Back 11

Locus Heterogeneity

Hint 11

Marfan's, MEN 2B, homocystinuria all cause marfanoid habitus.
Albinism

Front 12

Presence of both normal and mutated mtDNA, resulting in variable expression in mitochondrial inherited disease.

Back 12

Heteroplasmy

Hint 12

--

Front 13

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

Back 13

Uniparental disomy

Hint 13

--