Dihybrid Cross worksheet
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Name___________________ Date_________ Class_________ 1. In summer squash, white fruit color (W) is dominant over yellow fruit color (w) and disk-shaped fruit (D) is dominant over sphere-shaped fruit (d). If a squash plant that is homozygous for white, disk-shaped fruit is crossed with a plant that is homozygous for yellow, sphere-shaped fruit, what will the phenotypic and genotypic ratios be for Genotype Phenotype 2. Tall tomato plants are produced by TT and dwarf plants by its recessive allele tt. Hairy stems are produced by a dominant gene HH and hairless stems by its recessive allele hh. A heterozygous tall, hairy plant is crossed with a dwarf hairless tomato plant. Genotype Phenotype 3. Black coat (B) color in Cocker Spaniels is dominant, while red coat (b) color is recessive; solid pattern (S) is dominant, while spotted (s) pattern is recessive. A solid black male (BBSs) is mated to a solid red female (bbSs). Genotype Phenotype 4. In celery the leaves can be curly or straight, curly is dominant over recessive. LL= curly, ll=straight. The other trait is spots on the leaves. Dark green spots are dominant over white spots. Use GG for dark green, and gg for white. This is a dihybrid cross. Cross two heterozygous plants. Genotype Phenotype Extra Credit You are a world-famous breeder of Purple-People Eaters ("PPE"). Tragically, your entire stock perishes in a fire except for two individuals. They are both heterozygous for all three traits desired. EeHhFf x EeHhFf The three traits are as follows: EE/Ee-two eyes ee-one eye HH/Hh-two horns hh-one horn FF/Ff-non flying ff-flying The traits that bring the big bucks ($100 each) are "one eyed, one horned, flying" purple people eaters. If you breed the remaining two PPE, what distributions of traits will you get? Of these, how many will have all three of the traits that you will be able to sell for those big bucks? 1. Answer Key Ratio Genotype WWDD x wwdd WD WD WD WD Ww Dd Ww Dd Ww Dd Ww Dd wd Ww Dd Ww Dd Ww Dd Ww Dd wd Ww Dd Ww Dd Ww Dd Ww Dd wd Ww Dd Ww Dd wd Ww Dd th th Ratio Genotype Th tH Phenotype th TtHh Tthh ttHh tthh TtHh Tthh ttHh tthh TtHh Tthh ttHh tthh TtHh Tthh ttHh tthh th th 16 WwDd White,disk-shape Ww Dd 2. TtHh x tthh TH Phenotype 4/16 4/16 4/16 4/16 TtHh Tthh ttHh tthh Tall, Hairy Tall, Hairless Dwarf, Hairy Dwarf, Hairless 3. BBSs x bbSs Ratio Genotype BS bS bs bS bs Bs BS Bs Bb SS BbSs Bb SS BbSs BbSs Bbss BbSs Bbss Bb SS BbSs Bb SS BbSs BbSs Bbss BbSs Bbss 4. LlGg x LlGg 4/16 BbSS 8/16 BbSs 4/16 Bbss Black, Solid Black, Solid Black, Spotted Ratio Genotype LG Lg lG LL GG LL Gg Ll GG Ll Gg Lg LL Gg LL gg Ll Gg Ll gg lG Ll GG Ll Gg ll GG ll Gg lg Ll Gg Ll gg ll Gg ll gg LG Phenotype lg 1/16 LLGG 2/16 LLGg 2/16 LlGG 4/16 LlGg 2/16 Llgg 1/16 llGG 2/16 llGg 1/16 llgg Phenotype Curly,green Curly,green Curly,green Curly,green Curly,white Straight, green Straight, green Straight, white 5. EeHhFf x EeHhFf EHF EhF EHf EHF EhF EEHHFF EEHhFF EHf Ehf eHF ehF eHf ehf EEHHFf EEHhFf EeHHFF EeHhFF EeHHFf EeHhFf EEhhFF EEHhFf EEhhFf EeHhFF EehhFF EeHhFf EehhFf EEHhFf EEHHff EEHhff EeHHFf EeHhFf EeHHff EeHhff EEhhFf EEHhff EEhhff EeHhFf EehhFf EeHhff Eehhff EEHhFF EEHHFf Ehf EEHhFf eHF EeHHFF EeHhFF EeHHFf EeHhFf eeHHFF eeHhFF eeHHFf eeHhFf EEHhFF EehhFF EeHhFf EehhFf eeHhFF eehhFF eeHhFf eehhFf EeHhFf EeHHff EeHhff eeHHFf eeHhFf eeHHff eeHhff EehhFf EeHhff Eehhff eeHhFf eehhFf eeHhFf eehhff ehF eHf ehf EeHHFf EeHhFf
