Topic 7: Mutation

Question 1

mutation

Answer 1

• ultimate source of all variation in populations; without mutation there can be no variation and no evolution
• heritable change in DNA seq/complement (# chromosomes)

Question 2

paralogous

Answer 2

genes that are duplicated within a genome and diverge in function such as the hemoglobin genes

Question 3

orthologous meaning

Answer 3

genes that share a common ancestral seq, and separated by a speciation event

Question 4

what does the infinite alleles model assume?

Answer 4

each new mutation will create a new unique allele.
under the infinite alleles model, ALL COPIES of any give allele will be identical by descent, bc each allele arises only once!

Question 5

infinite sites model

Answer 5

• only one mutation can occur at each site in a nucleotide sequence alignment
• each site can possess a MAX of 2 diff nucleotides
• more conservative than infinite alleles model -> fewer ways that new alleles can evolve
• ALL copies of an ALLELE are identical by descent!

Question 6

stepwise mutation model

Answer 6

• microsatellite alleles mutate by gain or loss of repeats
• length of alleles incrementally increases or decreases ONE REPEAT at a time via mutation
• copies of same allele MAY NOT be identical by descent

Question 7

T/F all synonymous mutations are neutral

Answer 7

False! Codon bias

Question 8

positive selection
- acts to?
- results in?

Answer 8

acts to increase freq of advantageous mutations

results in adaptive evolution

Question 9

why does mutation not create HW disequil?

Answer 9

mutation occurs in gametogenesis; gametes can have slightly different allele freq than adults due to mutation, but with random mating, we have random union of gametes!

although allele freq may be a bit different, those gametes will unite -> zygote, according to HW equil
- note this is based on new allele freq after mutation occurs

Question 10

mutation changes allele freq slowly or quickly?

Answer 10

slowly