Basic Genetic Terminology
One half of a replicated chromosome
What is a Chromatid
Point mutations that do not change the resulting amino acid
What is a Silent Mutation
An inheritance pattern in which a person is affected when one of two gene copies has a pathogenic variant.
What is Autosomal Dominant Inheritance
When a population size is greatly reduced, the genetic diversity of the remaining smaller population is limited.
What is a Bottleneck
A portion of a persons cells have a typical genetic makeup and a subset of cells have a mutation or genetic difference.
What is Mosaicism
The short arm of a chromosome is the _ arm and the longer arm is the _ arm.
What is the P arm (shorter) and the Q arm (longer)
A point mutation that changes the codon to a stop codon
What is a Nonsense Mutation
When a condition has this inheritance pattern, there is a 25% chance for a child of two carriers to be affected.
What is Autosomal Recessive Inheritance
Reduction in genetic diversity that occurs when a small group is separated from a larger population. A genetic variant in this small population can become more prevalent.
What is the Founder Effect
Two copies of a chromosome come from one parent and none from the other parent.
What is Uniparental Disomy
A point mutation that changes the resulting amino acid.
What is a Missense Mutation
An inheritance pattern in which a pathogenic variant will be passed on from mom to all children.
What is Mitochondrial Inheritance
Process where genes move from one population to another; can occur through migration
What is Gene Flow
A type of disorder caused by expansions of repeating segments of three nucleotides.
What are Triplet Repeat Disorders
Variable Expressivity
An insertion or deletion that is a multiple of 3 bases, in which the reading frame remains intact.
What is an In-Frame Mutation
An inheritance pattern in which women are typically unaffected carriers while males are affected.
What is X-Linked Inheritance
Change in allele frequencies due to random events or chance such as individuals dying or not reproducing; makes a greater impact in smaller populations.
What is Genetic Drift
If a person has a disorder, this best describes how often a test will detect it.
What is Sensitivity
Occurs when there is a deletion at both ends of the chromosome and the ends fuse.
What is a Ring Chromosome
An insertion or deletion that is not a multiple of 3 bases, in which the reading frame shifts.
What is a Frameshift Mutation
What is the estimated recurrence risk to siblings for parents with a child with a de novo variant?
Bonus: Why is it quoted this?
What is 1% (due to germline mosaicism)
Describes a baseline where allele and genotype frequencies remain constant in the absence of evolutionary forces (no selection, drift, etc.)
What is Hardy-Weinberg Principle
If a test is negative, this best describes how likely it is that a patient does NOT have the disorder.
What is the Negative Predictive Value