Lecture 2 Flashcards
(16 cards)
What percentage of the human genome is responsible for genetically determined variation?
0.5%
This variation affects anatomy, physiology, dietary intolerances, susceptibilities to infections, and responses to medicines.
What are the types of genetic variation mentioned?
- Anatomy
- Physiology
- Dietary intolerances
- Susceptibilities to infections
- Responses to medicines
- Personality traits
- Artistic talent
- Athletic aptitude
These variations arise from the 0.5% of the genome that differs between individuals.
What is the human genome approximately composed of?
3 billion base pairs
Two random unrelated individuals have 99.5% identical DNA sequence.
What is the difference between polymorphisms and mutations?
Polymorphisms are common sequence variations, while mutations are deviations away from normal common variants.
Mutations can be neutral, advantageous, or disadvantageous.
What are the three effects of mutations on gene products?
- Neutral
- Advantageous
- Disadvantageous
Disadvantageous mutations can lead to genetic diseases.
What determines the effect of a mutation on its gene product?
- Type of mutation
- Location in gene
- Location in 3D protein structure
The location can also include non-coding RNA sequences.
What are chromosomal mutations?
Changes in the number of chromosomes due to missegregation during meiosis.
These mutations often lead to severe gene dosage consequences.
What are subchromosomal mutations?
Changes involving chunks of chromosomes.
These also have severe gene dosage consequences.
What are the types of Subchromosomal mutations?
- Deletion
- Duplication
- Insertion
- Inversion
- Translocation
What are DNA mutations?
Smaller alterations to the DNA sequence caused by replication errors or DNA damage.
They are the most common viable human mutations.
What are point mutations?
Single nucleotide substitutions that can be synonymous or non-synonymous.
Non-synonymous mutations can create premature stop codons, leading to truncated proteins.
What is an indel mutation?
Insertion or deletion of a small number of bases.
Indels not in multiples of 3 nucleotides cause frame-shift mutations.
What are dynamic mutations?
Expansion of polymorphic DNA repeat sequences beyond a copy number threshold.
This can lead to diseases like Huntington’s disease.
What are somatic mutations?
Mutations that occur in somatic cells during an individual’s life and cannot be inherited.
Only the cells derived from the mutated cell will carry the mutation.
What are germline mutations?
Mutations that occur in gametes and can be inherited by offspring.
All cells in the body of the offspring will carry the mutation.
What influences the severity of somatic mutations?
When the mutation occurred during development.
The timing can affect the extent of the mutation’s impact.
