Sweet yellow tomatoes with a pear shape bring a high price per basket to growers. Pear shape, yellow color, and terminal flower position are recessive traits produced by alleles f, r, and t, respectively. The dominant phenotypes for each trait—full shape, red color, and axial flower position—are the product of dominant alleles F, R, and T. A farmer has two pure-breeding tomato lines. One is full, yellow, terminal and the other is pear, red, axial. Design a breeding experiment that will produce a line of tomato that is pure-breeding for pear shape, yellow color, and axial flower position.
Table of contents
- 1. Introduction to Genetics51m
- 2. Mendel's Laws of Inheritance3h 37m
- 3. Extensions to Mendelian Inheritance2h 41m
- 4. Genetic Mapping and Linkage2h 28m
- 5. Genetics of Bacteria and Viruses1h 21m
- 6. Chromosomal Variation1h 48m
- 7. DNA and Chromosome Structure56m
- 8. DNA Replication1h 10m
- 9. Mitosis and Meiosis1h 34m
- 10. Transcription1h 0m
- 11. Translation58m
- 12. Gene Regulation in Prokaryotes1h 19m
- 13. Gene Regulation in Eukaryotes44m
- 14. Genetic Control of Development44m
- 15. Genomes and Genomics1h 50m
- 16. Transposable Elements47m
- 17. Mutation, Repair, and Recombination1h 6m
- 18. Molecular Genetic Tools19m
- 19. Cancer Genetics29m
- 20. Quantitative Genetics1h 26m
- 21. Population Genetics50m
- 22. Evolutionary Genetics29m
2. Mendel's Laws of Inheritance
Monohybrid Cross
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
A black and white rabbit were mated. All F1 offspring were black, and the F2 offspring is made up of approximately ¾ black and ¼ white rabbits.
• Draw out two Punnet squares detailing both matings.
• Supposed two white F2 offspring were mated. What would be the phenotype and genotype of the F3 offspring?
A
White, aa
B
White, Aa
C
Black, Aa
D
Black AA

1
Step 1: Identify the genotypes of the parent rabbits. The black rabbit is likely homozygous dominant (BB) or heterozygous (Bb), while the white rabbit is homozygous recessive (bb). Since all F1 offspring are black, the black parent must be heterozygous (Bb).
Step 2: Draw the Punnett square for the F1 generation. Cross the heterozygous black rabbit (Bb) with the homozygous recessive white rabbit (bb). The possible genotypes for the F1 offspring are Bb and bb, but since all F1 are black, Bb is the dominant phenotype.
Step 3: Draw the Punnett square for the F2 generation. Cross two F1 heterozygous black rabbits (Bb x Bb). The possible genotypes are BB, Bb, and bb. The phenotypic ratio is 3 black (BB and Bb) to 1 white (bb).
Step 4: Consider the mating of two white F2 offspring. Since they are both white, their genotype must be homozygous recessive (bb). When two bb rabbits are mated, all F3 offspring will be white with the genotype bb.
Step 5: Review the possible genotypes and phenotypes for the F3 generation. Since the F3 offspring are from two white (bb) parents, they will all be white with the genotype bb. This confirms the phenotype and genotype of the F3 offspring as white, bb.
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Monohybrid Cross practice set
