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
2:20 minutes
Problem 10a
Textbook Question
Textbook QuestionIn chickens, a condition referred to as 'creeper' exists whereby the bird has very short legs and wings and appears to be creeping when it walks. If creepers are bred to normal chickens, one-half of the offspring are normal and one-half are creepers. Creepers never breed true. If bred together, they yield two-thirds creepers and one-third normal. Propose an explanation for the inheritance of this condition.
Verified Solution
This video solution was recommended by our tutors as helpful for the problem above
Video duration:
2mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Incomplete Dominance
Incomplete dominance occurs when the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes. In the case of the 'creeper' chickens, the presence of the creeper allele may not completely mask the normal allele, leading to a mix of normal and creeper offspring when bred with normal chickens.
Recommended video:
Guided course
04:37
Variations on Dominance
Lethal Alleles
Lethal alleles are alleles that can cause the death of an organism when present in a homozygous state. In the creeper chickens, the fact that creepers never breed true suggests that the homozygous condition for the creeper allele may be lethal, resulting in a higher proportion of normal offspring when bred with normal chickens.
Recommended video:
Guided course
03:03
New Alleles and Migration
Genotypic Ratios
Genotypic ratios describe the relative frequencies of different genotypes in the offspring of a genetic cross. The observed ratios in the creeper chicken crosses (1:1 and 2:1) indicate a specific inheritance pattern, suggesting that the creeper trait is influenced by a single gene with two alleles, where one allele is lethal in the homozygous state.
Recommended video:
Guided course
07:52
Gamete Genotypes
Watch next
Master Monohybrid Cross with a bite sized video explanation from Kylia Goodner
Start learningRelated Videos
Related Practice