L8 Gerenartion of genetic diversity(Sheet1) Flashcards
Genetic Diversity
Variability in genetic makeup among individuals.
Mutation
Change in DNA sequence driving evolution.
Karyotypic Changes
Alterations in chromosome structure or number.
When do mutations arise?
1.During DNA replication
2.Through DNA damage
DNA Replication Error Rate
1 error per 100,000 nucleotides.
What are the two methods to fix DNA error rate?
- Polymerases have ‘proof reading’ domains
- Missmatch repair
Proofreading Domains
Polymerase features correcting DNA replication errors.
Mismatch Repair
Mechanism fixing incorrectly paired DNA bases.
Base-Excision Repair
Repair process for oxidative DNA damage.
Transition Mutation
Substitution between purines or pyrimidines.
Transversion Mutation
Substitution between purines and pyrimidines.
Silent Mutation
A change in DNA that does not effect the amino acid and protein function.
Missense Mutation
Amino acid change due to single base substitution.
Frameshift Mutation
Insertion or deletion causing misreading of codons.
Nonsense Mutation
Mutation creating a premature stop codon.
Sequence Divergence
Evolutionary changes in DNA sequences over time. Mutation rate is relatively fixed over time. so, DNA sequence similarity can be used as a measure of evolutionary time.
What is Nomenclature of missense muation used for?
A mutation that changes an amino acid st a specific position in aprotein.i.e., A521E (A=what the amino acid was, 521= the location in the polypeptide, E= what the amino acid is now changed into)
Particular nomenclature is used to describe where mutations have happened.
Conserved Sequences
Essential genes maintained across species.
Genome Instability
Increased mutation rates leading to evolutionary change.
Cancer Karyotypes
Extreme genetic diversity associated with cancer.
HIV Resistance
35bp deletion in CCR5 gene provides immunity.
Natural Selection
Process favoring advantageous genetic variations.
Polymerases
Enzymes responsible for DNA synthesis.
SARS-Cov-2 Mutation
N501Y mutation affects Spike protein function.