Topic 4

Question 1

Crossing over

Answer 1

force that generates recombination in linked genes

Question 2

Chromosome map

Answer 2

Order of genes and their coordinates on the chromosome

Question 3

Genetic linkage is the major _______ to the 2nd law

Answer 3

exception

Question 4

What causes recombinants?

Answer 4

crossing over

Question 5

Frequency of recombination

Answer 5

the average # of crossing over between the genes

Question 6

Test cross in frequency of recombinants

Answer 6

the frequency of recombinant phenotypes is equal to the frequency of the recombinant gametes in the hybrid

Question 7

Coupling

Answer 7

both the recessive alleles are in 1 parental

Question 8

Repulsion

Answer 8

one recessive allele in each parent

Question 9

When does crossing over happen?

Answer 9

in meiosis 1, after DNA replication. It impacts 2 out of 4 chromatids and produces 50% parent gametes and 50% recombinant

Question 10

Recombination between gentically linked genes is always ______________

Answer 10

less than 50%

Question 11

What does the frequency of recombination measure?

Answer 11

the intensity of linkage

Question 12

What is recombination caused by?

Answer 12

a physical change between the homologous chromosomes in prophase of the 1st meiotic division and after S-phase

Question 13

What determines the frequency (likelihood) of crossing over?

Answer 13

the physical distance between genes

Question 14

syntenic

Answer 14

genes on the same chromosome that over 50mu apart. They are still linked but basically do the same thing as unlinked genes

Question 15

Why is it difficult to correctly get RF in a F2 cross

Answer 15

recessive recombination could be hidden by dominant parental genotypes

Question 16

crossover interference

Answer 16

prevents multiple crossing overs occurring close together

Question 17

_______ RF’s predict less accurate genetic distances

Answer 17

Large