Dihybrid Cross Worksheet

Name: __________________________ Period: _____ Date: _________________ Dihybrid Cross Worksheet In#rabbits,#gray#hair#is#dominant#to#white#hair.#Also#in#rabbits,#black#eyes#are#dominant#to#red#eyes.#These#letters# represent#the#genotypes#of#the#rabbits:# ! 1.#What#are#the#phenotypes#(descriptions)#of#rabbits#that#have#the#following#genotypes?# white hair with black eyes eyes white hair with gray hair with black ggbb#____________________#GgBb#_________________________# red eyes eyes gray hair with red Ggbb#____________________#ggBB#________________________# 2.#A#male#rabbit#with#the#genotype#GGbb#is#crossed#with#a#female#rabbit#with#the#genotype#ggBb#the#square#is#set#up# below.#Fill#it#out#and#determine#the#phenotypes#and#proportions#in#the#offspring.# How#many#out#of#16#have#gray#fur#and# black#eyes?#________## 8 GgBb GgBb GgBb GgBb GgBb GgBb Ggbb Ggbb Ggbb Ggbb Ggbb Ggbb Ggbb Ggbb GgBb GgBb How#many#out#of#16#have#gray#fur#and#red# eyes?#________# 8 How#many#out#of#16#have#white#fur#and# black#eyes?#________# None How#many#out#of#16#have#white#fur#and# red#eyes________# none # 3.#A#male#rabbit#with#the#genotype#GgBb#is#crossed#with#a#female#rabbit#with#the#genotype#GgBb#The# 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# black#eyes?#________# 10 GGBB GGBb GgBB GgBb GGBb GGbb GgBb Ggbb GgBB GgBb ggBB ggBb GgBb Ggbb ggBb ggbb How#many#out#of#16#have#gray#fur#and#red# 2 eyes?#________# How#many#out#of#16#have#white#fur#and# 3 black#eyes?#________# How#many#out#of#16#have#white#fur#and# red#eyes?#________# 1 4.#Show#the#cross#between#a#ggBb#and#a#GGBb.#You'll#have#to#set#this#one#up#yourself:## Punnett#Square:# GB gB Gb GgBB GgBb GB GgBB Gb GgBb gb GgBb Ggbb GgBb gB GgBB GgBb GgBB Ggbb GgBb gb GgBb Ggbb GgBb Ggbb ! 5.#An#aquatic#arthropod#called#a#Cyclops#has#antennae#that#are#either#smooth#or#barbed.#The#allele#for# barbs#(B)#is#dominant#over#smooth#(bb).#In#the#same#organism#NonTresistance#to#pesticides#(N)#is#dominant# over#resistance#to#pesticides#(nn).#Make#a#"key"#to#show#all#the#possible#genotypes#(and#phenotypes)#of#this# organism.# Genotype Phenotype Barbed Barbed BB!! Bb!! bb!! NN!! Nn!! nn!! ! Smooth Non-resistant Non-resistant Resistant 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#of#the#parents.# Bbnn BbNn ______________#x#_______________# 7.#Set#up#a#punnett#square#for#the#cross.# bn BbNn BN Bn bN bn Bbnn bn bn BbNn BbNn Bbnn Bbnn bn BbNn Bbnn bbNn bbNn bbNn bbNn bbnn bbnn bbnn bbnn ! 8.#What#are#the#phenotypic#ratios#of#the#offspring?## Barbed and non-resistant -4 Barbed and resistant- 4 Smooth and non-resistant- 4 # Smooth and resistant- 4 # # 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 black mouse RB RB RB RB RRBB x Rrbb Parental genotypes ______________ RRBb _____ RrBB _____ _____ Rb Possible gametes _____ 16:0:0:0 Offspring phenotypic ratio ________________ Rb ! RRBb ! ! RRBb ! RRBb !RRBb ! RRBb !RRBb ! RRBb rb !RrBb ! RrBb ! RrBb ! RrBb rb ! RrBb ! RrBb ! RrBb ! RrBb RRBb b. Cross a homozygous running, homozygous black mouse with a heterozygous running, brown mouse RB rB rb Rb Rr x RRBB Parental genotypes ______________ ! ! ! ! RBRB RrBb RrBB RrBb Possible gametes _____ _____ _____ _____ RB RBRB 16:0:0:0 RRBb RrBB RrBb Offspring phenotypic ratio ________________ ! ! ! ! RB RrBb RRBb RBRB RrBB ! ! ! ! RRBb RrBB RrBb RB RBRB ! ! ! ! RBRB RRBb RrBB RB RrBb c. Cross a waltzing brown mouse with a waltzing brown mouse rrbb x rrbb Parental genotypes ______________ rrbb _____ _____ _____ Possible gametes _____ 16:0:0:0 Offspring phenotypic ratio ________________ rb ! rb ! rb rb ! ! rb rrbb rrbb rrbb rrbb rb ! rb rb rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb ! rrbb d. Cross a homozygous running, heterozygous black mouse with a waltzing brown mouse RB RB Rb RB RRBb x rrbb Parental genotypes ______________ ! ! ! ! Rrbb _____ _____ RrBb _____ Possible gametes _____ 8:8:0:0 rb RrBb RrBb Offspring phenotypic ratio ________________ Rrbb Rrbb ! RrBb ! rb ! RrBb ! rb ! RrBb ! rb Rrbb Rrbb ! RrBb ! Rrbb ! RrBb ! Rrbb RrBb ! Rrbb ! Rrbb e. Cross a heterozygous running, brown mouse with a heterozygous running, homozygous black mouse Rb rb Rb rb Rrbb x rrbb Parental genotypes ______________ RrBb _____ rrBb _____ RB RRBb _____ Possible gametes _____ 12:4:0:0 Offspring phenotypic ratio ________________ RB rB rB ! ! RRBb ! RRBb ! RrBb ! ! RrBb ! RRBb RRBb ! ! ! RrBb RrBb ! RrBb ! RrBb ! rrBb ! rrBb rrBb ! rrBb RrBb ! RrBb f. Cross a heterozygous running, heterozygous black mouse with a heterozygous running, heterozygous black mouse RrBb x RrBb Parental genotypes ______________ Possible gametes _____ _____ _____ _____ 9:3:3:1 RB Offspring phenotypic ratio ________________! ! ! ! Rb RRBB, RRBb, RrBB, RrBb RRbb, Rrbb, rrBb, rrBB, rrbb RB Rb rB ! RRBB ! ! ! RRbb ! ! ! rB ! RRBb ! RrBB rb ! RrBB ! RRBb RrBB RrBb RrBb Rrbb ! rb ! RrBb ! Rrbb rrBB ! rrBb rrBb ! rrbb