17.1 Genes and Variation

Question 1

How is evolution defined in genetics terms?

Answer 1

Evolution, in genetic terms, involves a change in the frequency of alleles in a population over time.

Question 2

What are the sources of genetic variation?

Answer 2

Three sources of genetic variation:

1) mutation (due to copying DNA errors)
2) genetic recombination (gene shuffling during formation of gametes/meiosis)
3) lateral gene transfer (important for bacteria and viruses)

Question 3

What determines the number of phenotypes for a given trait?

Answer 3

whether the trait is controlled by one gene (single-gene trait) or if it is controlled by several genes (polygenic trait)

Question 4

What is a gene pool?

Answer 4

consists of all genes, including all the different alleles, that are present in a population

Question 5

What is allele frequency?

Answer 5

the number of times an allele occurs in a gene pool, compared to the total number of alleles for that same gene in that same gene pool

Question 6

What is a single-gene trait?

Answer 6

Trait controlled by one gene (so there will only be a few distinct phenotypes)

Question 7

What is a polygenic trait?

Answer 7

Trait controlled by multiple genes (poly=many) (so there will be a larger continuous range of phenotypes usually)