Term
|
Definition
| Gene diversity = expected number of differences per base between two randomly selected alleles from the population |
|
|
Term
|
Definition
| Number of copies in sample |
|
|
Term
| What is a coalescent event? |
|
Definition
| A time in the past where the number of ancestors is reduced by 1 |
|
|
Term
| What does it mean if theta is positive, negative or 0? |
|
Definition
positive = balancing selection
negative = selective sweep/recent population expansion
0 = as expected |
|
|
Term
| What is linkage disequilibrium? |
|
Definition
| The tendency for alleles to be inherited together |
|
|
Term
|
Definition
Mutation - creates new haplotypes
Population subdivision - associations for unlinked genes
Genetic drift
Selection |
|
|
Term
| Why does the mutation rate appear to decrease as population size increases? |
|
Definition
| 'Nearly' neutral mutations are less likely to be removed via selection in a small population, as weak selection is only effective in larger populations |
|
|
Term
| When is genetic variation effectively neutral? |
|
Definition
| When Nes is less than one, where s is the strength of selection |
|
|
Term
| Why is codon bias under weak selection? |
|
Definition
| tRNAs are not equally abundant- using more abundant ones can make the process slightly quicker- would only have an effect in a large population, as to not have it will only have a tiny effect on fitness |
|
|
Term
| How could introns be deleterious? |
|
Definition
| If the mutation rate changes preventing intron removal (seriously? this is reaching a bit John) |
|
|
Term
| Why might genome size increase? |
|
Definition
| formation of pseudogenes and insertion of mobile DNAs |
|
|
Term
| Why do microorganisms have a smaller genome and more ordered DNA? |
|
Definition
| Higher Ne = higher selective force |
|
|
