Lecture 2+3

Question 1

Define ‘microevolution’.

Answer 1

Small scale changes in allele frequencies in a gene pool of a species, typically over a few generations.

Question 2

Define ‘macroevolution’.

Answer 2

Accumulation of microevolutionary change are sufficient to explain macroevolution, which refers to the evolution of differences among higher taxa from common ancestry.

Question 3

Define ‘DNA mutation’.

Answer 3

The process whereby the DNA sequence is changed because of a copying error during DNA replication and/or cell division.

Question 4

What are the main features of somatic mutations and give an example.

Answer 4

Occur in stoma (tissue)/ not heritable/ may cause disease e.g. substitution.

Question 5

What are the main features of germline mutations?

Answer 5

Heritable/ introduce genetic variability/ one of the main driving forces of evolution/ random process.

Question 6

Define ‘substitutions’.

Answer 6

Type of mutation where a spelling mistake is made, i.e. one base is accidently swapped for another.

Question 7

Define ‘insertions’ and ‘deletions’.

Answer 7

Type of mutation where an extra base is either accidently added onto a sequence or accidently removed.

Question 8

Define ‘synonymous DNA substitution’.

Answer 8

A mutation which does not change the amino acid sequence in the translated protein.

Question 9

Define ‘non-synonymous DNA substitutions’.

Answer 9

A mutation that does change the amino acid sequence in the translated protein.

Question 10

Define ‘frameshifts’.

Answer 10

Mutations that can have detrimental effects on DNA sequence. One base is removed causing codons to change throught the sequence.

Question 11

Define ‘lethal mutation’.

Answer 11

A mutation leads to a defective enzyme which could be fatal.

Question 12

Define ‘deletrious mutation’.

Answer 12

A mutation does not lead to death of organism but reducess fitness.

Question 13

Define ‘neutral mutation’.

Answer 13

Mutation does not effect protein structure, or occurs outwith a gene, or the mutant protein does not affect the fitness of the individual.

Question 14

Define ‘advantageous mutation’.

Answer 14

The mutation causes the organism to increase its overall fitness.

Question 15

Define ‘random genetic drift’.

Answer 15

The generation upon generation change in allele frequency due to random sampling among gametes.

Question 16

What effects do genetic drift have?

Answer 16

1. Change allele frequencies within a population. 2. Increase the variance in allele frequencies across populations. 3. Reduce heterozygosity within populations.

Question 17

What is the relationship between genetic drift and population size?

Answer 17

Effects of drift increase with decreasing population size. In extremely small populations random drift can lead to the fixation or loss of an allele.

Question 18

Define ‘effective population size’.

Answer 18

The size of an ideal theoretical population that will lose heterozygosity at the same rate as the actual population of interest.

Question 19

Define ‘gene flow’.

Answer 19

Genetically effective dispersal.

Question 20

Define ‘Hardy-Weinberg’.

Answer 20

The ability to predict genotype frequencies from allele frequencies in the absence of microevolution and can therefore be used to determine if micro evolution is taking place.