What is the fundamental definition of human genetic variation?
It refers to the DNA sequence variations that occur between individuals and within a population.
Inherited variation, also known as _____ variation, is associated with the process of meiosis.
constitutional
What are the two primary types of genetic variation?
Inherited (Constitutional) variation and Acquired (Post-zygotic) variation.
Acquired variation, also known as _____ variation, occurs throughout an individual’s life.
post-zygotic
In which types of cells does inherited (constitutional) variation manifest?
It is present in both somatic cells and the germline.
How does the prevalence of acquired variation change with an individual’s age?
It accumulates with age.
What is an example of a normal, programmed cell-specific change that causes acquired variation?
The changes that occur in B-cells.
Besides programmed changes, what are four other mechanisms that cause acquired variation?
DNA replication/segregation errors, endogenous damage, exogenous damage, and DNA repair errors.
What are the two main types of endogenous chemical damage to DNA?
Hydrolytic damage and oxidative damage.
What are the three potential consequences of hydrolytic damage to DNA?
Base deletion, deamination (e.g., C>U), and single- or double-strand breaks.
The deamination of cytosine (C) to uracil (U) through hydrolytic damage can ultimately lead to what base pair transition?
A C:G base pair becomes a T:A base pair.
What type of molecules cause oxidative damage to DNA?
Reactive Oxygen Species (ROS).
What are the two main consequences of oxidative damage to DNA?
Base modification and single- or double-strand breaks.
What are the two categories of agents responsible for exogenous DNA damage?
Physical agents and chemical agents.
What type of DNA damage is typically caused by UV-radiation?
Intrastrand cross-linking.
What is a primary source of ionising radiation that causes exogenous DNA damage?
X-rays.
What type of damage is caused by ionising radiation like X-rays?
Single- or double-strand breaks.
What is a major type of DNA damage caused by chemical agents like mutagens and intercalating dyes?
Interstrand cross-linking.
What is a specific example of undetected DNA damage that can lead to a mutation?
The conversion of 5-methylcytosine (5-meC) to thymine (T).
What is the common outcome of incorrectly repaired DNA damage?
It often results in a single nucleotide substitution.
What are the two broad categories of genetic variation based on their effect on DNA content?
Balanced and unbalanced (Copy Number Variation).
A genetic change with no net loss or gain of DNA sequences is classified as a _____ variation.
balanced
What defines an unbalanced genetic variation?
A net loss or gain of DNA sequences, also known as Copy Number Variation (CNV).
In which genomic regions is the number of variants per kilobase (Kb) the smallest?
Coding regions.
