C3: Beyond Mendelian Genetics

Question 1

what is incomplete dominance?

Answer 1

when a heterozygote has a blended phenotype
ex: red and white flowers produce a pink flower

Question 2

what is codominance?
- what is an important example of this?

Answer 2

when a heterozygote expresses both phenotypes, not blended
ex: human blood type (O, A, B, AB) and rhesus factor (positive or negative)

Question 3

what is epistasis?

Answer 3

when one gene controls another

Question 4

what is independent assortment?
- recombination/ crossing over happens ____ (frequently/ less frequently)
- ____ (equal/unequal) probabilities of allele combinations in gametes

Answer 4

when genes are on the same chromosome but more than 50 map units apart
- frequently
- equal

Question 5

how many pairs of homologous chromosomes do women have?
- men?

Answer 5

• women, 23
• male, 22

Question 6

what genders gamete determines the sex of an embryo?

Answer 6

males

Question 7

when a parental cell undergoes meiosis under independent assortment, what is the outcome?

Answer 7

4 gametes, half parental outcomes and the other half recombinants. always end up w an equal combination (25% all around)

Question 8

what is a linked gene?
- recombination/ crossing over happens ____ (frequently/ less frequently)
- ____ (equal/unequal) probabilities of allele combinations in gametes

Answer 8

• genes are on the same chromosome but less than 50 map units apart
• less frequently
• unequal

Question 9

when a parental cell undergoes meiosis under linked genes, what is the outcome?

Answer 9

4 gametes, mostly half parental and have recombinants BUT unequal combination (less than 25% since recombination is difficult)