Genetics 7

Question 1

independent assortment

Answer 1

genes on different chromosomes line up independently from one another; 2n

Question 2

linkage

Answer 2

genes are located on the same chromosome; these genes will segregate but are not independent from each other

Question 3

as the distance between two genes increases,

Answer 3

so does the probability that they will crossover with the other sister chromatids

Question 4

in order for chrossing over to occur, the genes muxt be

Answer 4

incompletely linked

Question 5

best way to examine linked genes

Answer 5

use parent of interest crossed to a double homozygous recessive(test cross)

Question 6

what ratio is expected with a test cross

Answer 6

1:1:1:1

Question 7

how are linked genes written

Answer 7

all genes for one chromosome aer written together over the genes for its homologue eg: MD/md vs Mm Dd (ind assortment)

Question 8

what to do if you don’t know the genotype of heterozygote parent

Answer 8

take the parental type chromosome from the two most numerous offspring

Question 9

distance between genes

Answer 9

total # of recombinants/total # of offspring X 100 = % recombnination (1% recomb = 1 map unit)

Question 10

what ratio do linked genes produce

Answer 10

unequal

Question 11

if % recombination is over 50

Answer 11

assume independent assortment

Question 12

3 point linkage

Answer 12

examine 3 linked genes; determine map distance using only 1 cross (or 3, 1 is easier) by setting up a chart. Indicate in chart P for parental type and R(#) for recombinant

Question 13

genotype for offspring

Answer 13

entire chromosome of parent of interest over entire chromosome given by test cross parent

Question 14

gene order

Answer 14

write genotype in gene order, make sure middle gene on map is middle when writing.