Neutral Theory of Evolution

Question 1

Proposed by Motoo __

Answer 1

Kimura

Question 2

Neutral Theory of Evolution:

a. hypothesis that most alleles are ___ within populations and that become fixed do not __ alter fitness and evolve by genetic drift (most evolutionary changes and polymorphisms are ___ caused by natural selection, but by random __ drift)
b. Average time to fixation of a newly risen mutation equals __

Answer 2

a. polymorphic , significantly
NOT, genetic
b. 4Ne

Question 3

Two key observations underlie this theory:

a. Most __ populations have higher levels of genetic __ that would be expected if natural selection were the __ force
b. Most mutations don’t alter proteins __, so unlikely to be influenced by ___ selection

Answer 3

a. natural, variation, primary

b. encoded, natural

Question 4

The vast majority of alleles that are ___ are fixed by genetic ___

Answer 4

fixed, drift

Question 5

Fixed allele: all members of the population under study are ___, so that no other alleles for this locus exist in the ___

Answer 5

homozygous, population

Question 6

Molecular Clock: holds that mutations occur at a __ constant __

a. a tool to calculate the timing of __ events
b. First hypothesized by Linus ___ and Emile ___
c. Today’s definition: the number of changes __ in DNA or protein sequences in a given __

Answer 6

relatively, constant

a. evolutionary
b. Pauling, Zuckerland
c. accumulated, lineage

Question 7

Mutations in third __ base positions are __ than in second base___ in codons

Answer 7

base, higher, positions

Question 8

Probability that a mutations will be fixed by __ drift is:

1/ (2Ne)

Answer 8

genetic