The bacteriophage genome consists of many genes encoding proteins that make up the head, collar, tail, and tail fibers. When these genes are transcribed following phage infection, how are these proteins synthesized, since the phage genome lacks genes essential to ribosome structure?
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
5. Genetics of Bacteria and Viruses
Bacteriophage Genetics
Problem 18
Textbook Question
In an analysis of rII mutants, complementation testing yielded the following results:


1
Understand the concept of complementation testing: Complementation testing is used to determine whether two mutations are in the same gene or in different genes. If two mutants complement each other (indicated by '+'), it means their mutations are in different genes. If they do not complement (indicated by '-'), their mutations are in the same gene.
Analyze the given data: Mutants 1 and 2 complement (+), meaning their mutations are in different genes. Similarly, mutants 1 and 3 complement (+), so their mutations are also in different genes. However, mutants 1 and 4 do not complement (-), meaning their mutations are in the same gene. The same applies to mutants 1 and 5 (-).
Group the mutants based on the complementation results: Since mutants 1 and 4, as well as mutants 1 and 5, do not complement, mutants 4 and 5 are likely in the same gene as mutant 1. Mutants 2 and 3, which complement mutant 1, are in different genes.
Predict the results for mutants 2 and 3: Since mutants 2 and 3 complement mutant 1 and are in different genes, they are likely to complement each other. The predicted result for 2 and 3 is '+'.
Predict the results for mutants 2 and 4, and 3 and 4: Mutant 4 is in the same gene as mutant 1, while mutants 2 and 3 are in different genes. Therefore, mutants 2 and 4, as well as mutants 3 and 4, are predicted to complement each other. The predicted results for both 2 and 4, and 3 and 4, are '+'.

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
1mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Complementation Testing
Complementation testing is a genetic technique used to determine whether two mutations that produce a similar phenotype are in the same gene or in different genes. If two mutants complement each other (show a '+' result), it indicates that they are in different genes, as the wild-type function is restored. Conversely, if they do not complement (show a '-' result), it suggests that the mutations are in the same gene, preventing the restoration of function.
Recommended video:
Guided course
Complementation
rII Mutants
rII mutants are a class of mutations in the T4 bacteriophage that affect its ability to lyse bacterial cells. These mutants are often used in genetic studies to understand gene function and interactions. The rII region is particularly useful for complementation tests because it contains genes that can exhibit distinct phenotypes when mutated, allowing researchers to analyze genetic relationships and functional redundancy.
Recommended video:
Guided course
Organelle Inheritance
Genetic Interaction
Genetic interaction refers to the way in which different genes influence each other's expression and function. In the context of complementation testing, understanding genetic interactions helps predict the outcomes of combining different mutants. For example, if two mutants affect the same pathway or process, their interaction may lead to a specific phenotype, which can be inferred from previous results, guiding predictions about new combinations of mutants.
Recommended video:
Guided course
Interacting Genes Overview
Watch next
Master Plaques and Experiments with a bite sized video explanation from Kylia
Start learningRelated Videos
Related Practice
Textbook Question
922
views