Name: Toheera Phan Period Date
Chapter 10: Dihybrid Cross Worksheet
are dominant to red eyes. These letters
In rabbits, 8ray hair is dominant to white hair. Also in rabbits, black eyes
represent the genotypes of the rabbits:
GG gray hair BB black eyes
Gg gray hair Bb black eyes
88 white hair bb red eyes
1. What are the phenotypes (descriptions) of rabbits that have the following genotypes?
Ggb
inahait,#degee8 ukiheh,atk eyea
Rbb
_uwhike.h:,Mtto. GgBb grah black euta is set up
the square
. A male rabbit with the genotype GGbb is crossed with a female rabbit with the genotype ggBb
below. Fill it out and determine the phenotypes and proportions in the ofspring.
How many out of 16 have gray fur and
Gb Gb Gb Gb black eyes? 8 -
gBb 466 g8bB How many out of 16 have gray fur and
eyes? 8
red
gB G4 How many out of 16 have white fur and
black eyes?0-
How many out of 16 have white fur and
red eyesO
gb 966 4
with a female rabbit with the genotype GgBb The
3. A male rabbit with the genotype GgBb is crossed
square is set up below. Fill it out and determine the phenotypes and proportions of offspring
How many out of 16 have gray fur and
GB Gb gB gb black eyes?
How many out of 16 have gray fur and red
eyes? 2
Gb bb Pb 9g bb How many out of 16 have white fur and
black eyes?
How many out of 16 have white fur and
red eyes?
gb 6 bb 3 3gb
4. Show the cross between a ggBb and a GGBb. You'll have to set this one up yourself:
Punnett Square:
Gabb Bb bb
G6 B eb e Bb
5. An
4äbb Bb
aquatic arthropod called a Cyclops has antennae that either smooth barbed. The allele
are or
Tor
barbs(8is dominant over smooth (bb). In the same organism Non-resistance to pesticides (N) is dominant
overresistance
organism.
to pesticides (nn). Make a
"key" to show all the possible genotypes fand phenotypes) of this
Genotype Phenotypec
BB
Bb
Borbs
bb Barsbg
smobth
NN Non-r istance
Nn Non re4iStam te
nn
6. A Cyclops that is resistant to pesticides and has smooth antennae is crossed with one that is
heterozygous for both traits. Show the genotypes ofthe parents.
bhnn-xBhNn
7. Set up a punnett square for the cross.
bn bn bn bn
BN BbNn Bb Nn BbNn BbNn
Bn Bbnn Bbnn Bbnn Bbnn
bN bbNn bb Nn bbNn bbNn
bn bb nn bbnn bbn n bbn n
8. What are the phenotypic ratios of the offspring?
DiHybrid Practice Problems
. In man, assume that spotted skin (S) is dominant over non-spotted skin (s) and that
Wooly hair (W) is dominant over non-wooly hair (w). Cross a marriage between a
heterozygous spotted, non-wooly man with a heterozygous wooly-haired, non-spotrea
Woman. Give genotypic and phenotypic ratios of offspring. Ssww X CSWuw
Sswouledy)-y S S us
u;u:u
gww Cspotel ,non sgWuS Sawu9qwaWw atio
csWwmon spottaol
mooly-4 SWI Sw gww| 2W AAW
nonwoty)- 4
2. In horses, black is dependent upona dominant gene, B, and chestnut upon its recessive
allele, b. The trotting gait is due toa dominant gene, T, the pacing gait to îts recessve
allele, t. If a homozygous black pacer is mated to a homozygous chestnut trotter, what wi
be the appearance of the Figeneration? 8Btt XbbT
Bt Bt
B
F geneahon, TBSTt BbTt BbTt|BbTt
100 Blat, T BLTE B6Tt 8bTt 8bTt
othna bT 6Tt8bTt BbTtBbTt
BTt T B6TE BbTt 8bTt BTt
over yellow fruit color (w) and disk-
3. In summersquash, white fruit color (W) is dominant
fruit (d). If a squash plant true-breeding for
shaped fruit (D) is dominant over sphere-shaped for yellow, sphere-shaped fruit,
white, disk-shaped fruit is crossed with plant true-breeding
a
wwDD X wwdd WD WD WD
wD
wd Ww wwl WwDd wwDd
607. white,
dist-chaped wd
| wwDd wwDel |WwDd
ww Dd
w d w wDel wwbd wwDd wwDd
wwDd
wdwwDd |Wwbd Ww Do wwDol
5. In mice, the ability to run normally is a dominant trait. Mice with this trait are called
running mice (R). The recessive trait causes mice to run in circles only. Mice with this trait
are called waltzing mice (r). Hair color is also inherited in mice. Black hair (B) is dominant
over brown hair(b).For each of the following problems, determine the parent genotypes,
determine possible gametes then construct a Punnet square to solve.
a. Cross a heterozygous running, heterozygous black mouse with a homozygous running.
homozygous biack mouse
Pb
Parental genotypes RrBb x RR B8
Possible gametes RRBB R.Bb DreBPrBb
Offspring phenotypic ratio b i 0: 0: 0
Bb
Running blatk RBPRRB RR BbPr BB
Runnin brDwn RBBRT Bb
RB
RROBB
|RBb
waltiblauh.
wltayin o h y 8RRB RRBbRTBRTB
b. Cross a homozygous running, homozygous black mouse with a heterozygous running,
brown mouse
Re Re RB R8
Parental genotypes R6G XRTbb
Possible gametes 2RR Gb RRBb ppeb ARRb
Ospring phenotypic ratio L60: D: 0_
PbRRBb RBb RBb SD
RBb RP8b RRBb RR8b
b Rs Bb RRBb p8b RPB
c. Cross a watzing brown mouse with a waltzing brown mouse
Parental genotypes sbb x 7Tbb
Possible gametes
D'0: D: lL
Ofspring phenotypicratio bTsbb Tsbb
Tbb TY b6 Tbb
b bb
bsbb bb Tbb T7bb
rb TbbsbTbb Tbb
A-running -
w atzing B- blauk b-bown
d. Cross a homozygous running, heterozygous black mouse with a waltzing brown mous
Parental genotypes RRBb X1Tbb RB Rb RB
Possible gametes
Offspring phenotypic ratio 8 8 0 0
B Ar Bb Rsbr BbPbb
Qunnirg blatk BbRTbb
DB Rr Bb Pbb D
Runnir brown
Walti blatk B RBRbb R Bb PT
walirg brouwnu Rr Bb R b
7B Ry Bb Rbb
e. Cross a heterozygous running, brown mouse with a heterozygous running, homozygous
black mouse Pb
Rrbb X RYBB Pb
Parental genotypes EU2B8
Possible gametes. PB RRBb RRBb TBb Bb
Offspring phenotypic ratio u u y ,y
RB RRBb RRBb R Bb RTBb
B R B 71Bb 17
RrBb
eRrBb RBb B |T7 Pb
f. Cross a heterozygous running, heterozygous black mouse with a heterozygous running,
heterozygous black mouse
Parental genotypes ATBh XRY Bb RB Pb B b
Possible gametes
Offspring phenotypic ratio : 3 : 3 L RB RRB8 RRBb Rs BB Rr Bb
Pb RRB PRbb RT Bb R blo
YB ABB R Bb R TBBSTB
TbR8bRs bbpseb YTbb
RRBB TunNiry black
RRBb - 2 Yunniry black
RBB-2 Tun ni ng bluk
RT Bb-3 unningllack
PRbb | Tunu abouo n
R bb-2 ruNÀ ng' bown
TBBi waltair black
TDb-2 walina bl ath
T bb waui 6r0 uwn
1.Set up a punnett square using the following information:
Dominate allele for tall plants = D DW D Dw
Recessive allele' for dwarf plants d
Dominate allele for purple flowers W
Recessive allele for white flowers = w dw Ddww wDd W»|Dd Ww
Cross a homozyoous dominate parent
(DDWW) with a homozygous recessive parent
(ddww) dw Ddww Ddww Dd
ww Dd nw
2. Using the punnett square in question #1:
ww Ddww Dd
ww DdWw
a. What is the probablity of
producing tall plants with
duDd
purple flowers? t00) 0r lb}1b
Possible genotype(s)? D Ww Dd w» Ddww
b. What is the
dw Dd W Dd
probability of producing dwarf plants
with white flowers? 07.
Possible genotype(s)? None
c.What is the probability of producing tall plants with
white flowers? 0.
Possible genotype(s)? None
d. What is the probability of producing dwarf plants
with purple fiowers? 0.
Possible genotype(s)? None
3. Set up a punnett square using the following
BR B bR
information:
BBR bRR Bb RT
Dominate allele for black fur in guinea pigs = B
BR BB RR
Recessive allele for white fur in guinea pigs =b
Dominate allele for rough fur in guinea pigs =R
Recessive allele for smooth fur in guinea pigs = r
Cross a heterozygous parent (BbRr)with a
Br BBRY 88 |BbRy eb Tr
heterozygous parent (BbRr)
4. Using the punnett square in question #3:
a. What is the probability of producing guinea
bR BbRR BbR BbRR bbR
pigs with black, rough fur? q)lb
Possible genotype(s)?
BB RA BBA BbRR BbR br BbRBb BbR bbrr
b.What is the probability of producing guinea
pigs with black, smooth fur? 3/)b
P BbRr X 8b Rr
Possible genotype(s)? BB Bb o
c. What is the probability of producing guinea
pigswith white, rough fur? 2116
Possible genotype(s)? bbRR bbRDY
d. What is the probability of producing guinea
pigs with white, smooth fur? 1/1b
Possible genotype(s)? bbyr
