University:
Abraham Baldwin Agricultural College
Course:
BIOL3200K | Genetics
Academic year:

2020
Views:

362

Pages:

2
Author:

Marianna B

Genetics Practice Problems 1. For each genotype below, indicate whether it is heterozygous (He) or homozygous (Ho) AA Ho___ Bb He___ Cc He___ Dd He___ Ee He___ ff Ho___ GG Ho___ HH Ho___ Ii He___ Jj He___ kk Ho__ Ll He__ Mm He___ nn Ho___ OO Ho___ Pp He___ 2. For each of the genotypes below determine what phenotypes would be possible. Purple flowers are dominant to white Brown eyes are dominant to blue BB Brown______ Bb Brown______ bb Blue_________ PP Purple_______ Pp Purple________ pp White_________ Round seeds are dominant to wrinkled RR Round_________ Rr Round_________ rr Wrinkled_______ Bobtails are recessive (to long tails) TT long tails_____ Tt long tails _____ tt bobtails_______ 3. For each phenotype below, list the genotypes (remember to use the letter of the dominant trait) Straight hair is dominant to curly Tail spikes are dominant to plain tails SS___ straight SS__ spikes Ss___ straight Ss__ spikes ss__ plain ss___ curly 4. Set up the Punnett squares for each of the crosses listed below. Purple flowers are dominant to white. Rr x rr r Rr Rr rr rr Rr x Rr RR Rr Rr What percentage of the offspring will be round? _______ RR What percentage of the offspring will be round? _______ rr RR x Rr RR RR Practice with Crosses. Show all work! Rr 5. A TT (tall) plant is crossed with a tt (short plant). T T t Tt Tt t Tt Tt What percentage of the offspring will be tall? 100%_______ heterozygous for the trait. What percentage of the offspring will have purple flowers? 50%____ White flowers? 50%____ 6. Show the cross of a Tt plant and a Tt plant. T t T TT Tt t Tt tt 11. Two plants, both heterozygous for the gene that controls flower color are crossed. What percentage of the offspring will be short? 25%___ What percentage is tall? 75%____ 7. A heterozygous round seeded plant (Rr) is crossed with a homozygous round seeded plant (RR). R R R RR RR r Rr Rr What percentage of the offspring will be homozygous (RR)? 50%_____ What percentage of their offspring will have purple flowers? 75%______ What percentage will have white flowers? 25%______ 12. In guinea pigs, the allele for short hair is dominant. What genotype would a heterozygous short haired guinea pig have? Hh__ What genotype would a pure breeding short haired guinea pig have?hh__ 8. A homozygous round seeded plant is crossed with a homozygous wrinkled seeded plant. What are the genotypes of the parents? RR________ x rr________ What percentage of the offspring will also be homozygous? 0%______ What is the genotype of all of the offspring? RR_ 9. In pea plants purple flowers are dominant to white flowers. Two white flowered plants are crossed… What percentage of their offspring will have white flowers? 100%____ What genotype would a long-haired guinea pig have? HH__ Show the cross for two heterozygous guinea pigs. H h H HH Hh h Hh hh What percentage of the offspring will have short hair? 75%_____ What percentage of the offspring will have long hair? 25%____