Genetic Terms Flashcards
Codominance?
Both alleles contribute to phenotype of heterozygote
Variable expressivity?
Phenotype varies among indiiduals with same genotype
Incomplete penetrance?
Not all indiviuals with a mutant genotype show the mutant phenotype
Pleiotropy?
One gene contributes to multiple phenotypic effects?
Imprinting?
Differences in gene expression depend on whether the mutation is of maternal or paternal origin
Anticipation?
Increased severity or earlier onset of dz in succeeding generations
Loss of heterozygosity?
If a pt inherits or develops a mutation in a tumor suppressor gene, the complementary allele must be deleted/mutated before cancer develops (not true in concogenes)
Dominant negative mutation?
Exerts a dominant effect–heterozygote produces a nonfunctional altered protein that also prevents the normal gene product from functioning
Linkage disequilibrium?
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance–measured in a population, not family
Mosaicism?
Cells in body differ in genetic makeup due to postfertilization loss/change of genetic info during mitosis
Locus heterogeneity?
Mutations at different loci can produce the same phenotype
Heteroplasmy?
Presence of both normal and mutated mtDNA, resulting in variable expression in mitochondrial inherited dz
Uniparental disomy?
Offspring receives 2 copies of a Chr from 1 parent and no copies from the other parent
Blood groups A, B, AB?
Codominance
BRCA1 gene mutations?
Incomplete penetrance
