In your studies of the poison dart frog D. myersae, you discover that there are two
true breeding populations in the wild. Population 1 has bright red skin and population
2 has brilliant blue skin. You cross frogs from population 1 with frogs from population
2 (i.e. red frogs X blue frogs). The F1 progeny all have purple skin. You cross purple
F1’s to produce F2’s, and obtain the results shown below.!
!
!
!
!307 red frogs
!! bbR– or b–/b–, r+/r+or–!
! precursor! A! R! !red!
!298 blue frogs !! B–rr or b+/b+or–, r–/r –!
colorless
!
!
!
!883 purple frogs !! B-R- or b+/b+or–, r+/r +or–!
! precursor! B! B! !blue!
! 92 white frogs ! bbrr or !b–/b–, r–/r!–!
!
colorless
!
!
!
1580
!!
A. What are the genotypes of the F2 frogs?!
B. If you cross red F2 frogs X white F2 frogs, what is the probability of getting white
offspring?!
1/3! bbRR X bbrr!!
2/3! bbRr X bbrr!
all bbRr
1/2 bbRr
1/2 bbrr
!(red frogs)!
!(red frogs) !!
!(white frogs)!
Ans: (0 X 1/3) + (1/2 X 2/3) = 1/3!
In your studies of the poison dart frog D. myersae, you discover that there are two
true breeding populations in the wild. Population 1 has bright red skin and population
2 has brilliant blue skin. You cross frogs from population 1 with frogs from population
2 (i.e. red frogs X blue frogs). The F1 progeny all have purple skin. You cross purple
F1’s to produce F2’s, and obtain the results shown below.!
!307 red frogs
!!
BR!
Br!
bR!
br!
!298 blue frogs !!
!883 purple frogs !!
BBRR!
BbRr!
! 92 white frogs BR!
!
!
!BBRr!! BbRR!
!
!
!
!1580 !!
Br! BBRr!
BBrr!
BbRr!
Bbrr!
bR! BbRR! BbRr!
bbRR!
bbRr!
br!
bbRr!
bbrr!
BbRr!
Bbrr!
Where do 1/3 bbRR and 2/3 bbRr come from?! Of 3
squares that produce red phenotype 1 is bbRR (i.e. 1/3)
and 2 are bbRr (i.e. 2/3).!