Origin of Genetic Variation Flashcards
Why is variation critical to evolution?
Evolution can only happen with variation in characteristics, natural selection needs variation to be able to select individuals
What are silent/synonymous mutations?
Mutations that don’t change the amino acid encoded
What are non-synonymous mutations?
Mutations that change the amino acid encoded
What are gene mutations?
Alterations of genes or chromosomes
What are point mutations?
Alteration of a single base pair
What are base pair substitutions?
One base replaced by another, either transition or transversion
What are frameshifts?
Alteration in the reading frame which changes a bunch of amino acids downstream of the mutation. Caused by indels
What is intragenic recombination?
Difference in two or more base pairs in a gene, which generates a new sequence within the gene
What is gene conversion?
A damaged DNA strand on one chromosome is repaired based on an undamaged homologous chromosome
What causes unequal crossing over and what is the result?
Imperfect alignment between homologous chromosomes during bivalent formation. Results in an unequal exchange of genetic information and one chromosome with a duplication and the other with a deletion
How does the mutation rate compare to the size of the genome of the organism?
Mutation rates are generally pretty low, but tends to increase as the genome gets larger. The exception are viruses, which have high mutation rates to evade host defences
What are somatic mutations?
Mutations that occur in somatic cells and can’t be passed on to the next generation. They don’t matter for evolution
What are germline mutations?
Mutations in the reproductive cells that can be passed on and do matter for evolution because that change can be acquired by the next generation
What are homeotic mutations?
Mutations that can alter developmental processes and can cause an anatomical structure in the wrong place
Why are mutations limited for what can be changed in an evolutionary sense?
Mutations can only modify whats already there, and can’t alter developmental foundations
