Patterns Of Inheritance Flashcards
Genotype
Combo of genes at one locus on both chromosomes
Haplotype
Set of genes on neighboring loci on ONE chromosome
Phenotype
Outward manifestation of genotype
Compound heterozygote
Two different mutant alleles are present
Single gene disorder
Determined by alleles at one locus
Pleiotropic
A single abnormal gene can produce a wide variety of phenotypes
______ are disproportionately affected by single gene disorders
Children
Penetrance
Probability that a mutant genotype will produce an abnormal phenotype
Expressivity
Severity of the phenotypic manifestation of a disease genotype
Variable expressivity
Severity of disease differs in individuals with same genotype
Definition and synonyms for proband
Affected individual that initiates genetic consultation
Also called propositus or index case
Consultand
Person who brings family to the attention of a geneticist
Family of siblings is called
Sibship
Consanguineous
Couples with common ancestors
A genetic case is _______ if the proband is the only affected family member
Isolated
A genetic case is ______ if the isolated case is due to a new mutation
Sporadic
Patterns of inheritance shown by single gene disorders depend on these two factors
- Chromosomal location
2. Dominant or recessive phenotype
Autosomal recessive inheritance generally results in a _______ mutation
Loss-of-function
Most common ARD
Cystic fibrosis
Autosomal dominant inheritance comprises more than _____ of all Mendelian disorders
50%
Sex limited phenotype
Autosomal inherited but expressed only in one sex
X-linked dominant inheritance can be tracked by lack of _______ ________
Male-to-male transmission
Pseudoautosomal inheritance
Recombination between two homologous X chromosomes in females or between contiguous loci in X and Y chromosomes in males - can cause X-linked traits to appear autosomal
Mosaicism
Presence of two cell lineages that differ genetically but are derived from a single zygote
Allelic heterogeneity
different mutations in the same gene may produce the same phenotype
Locus heterogeneity
Mutations in different genes may cause the same phenotype
Clinical/phenotypic heterogeneity
Different mutations in the same gene may cause different phenotypes
Founder effect
Genetic drift that occurs when a sub population is isolated
Gene flow
Slow diffusion of genes across a barrier as in migration
Genetic admixture
Migrant populations’ characteristic allele frequencies merge with the new population
