In studies of recombination between mutants 1 and 2 from Problem 21, the results shown in the following table were obtained.Strain Dilution Plaques PhenotypesE. coli B 10⁻⁷ 4 rE. coli K12 10⁻² 8 +Mutant 7 (Problem 21) failed to complement any of the other mutants (1–6). Define the nature of mutant 7.

Verified step by step guidance

1. Identify the key information from the problem: Mutant 7 fails to complement any of the other mutants (1-6).
2. Understand the concept of complementation: Complementation occurs when two different mutations in the heterozygous state result in a wild-type phenotype. If two mutations do not complement each other, they are likely in the same gene.
3. Analyze the data provided: The table shows recombination results between mutants 1 and 2, with different plaque phenotypes on E. coli B and K12 strains.
4. Consider the implications of mutant 7 failing to complement: Since mutant 7 does not complement any of the other mutants, it suggests that mutant 7 has a mutation in the same gene as the other mutants.
5. Conclude the nature of mutant 7: Mutant 7 likely has a mutation in the same gene as mutants 1-6, indicating it is part of the same complementation group.

Key Concepts

Recombination

Recombination is a genetic process where genetic material is exchanged between different DNA molecules, leading to new combinations of alleles. This process is crucial for understanding genetic diversity and the inheritance of traits. In the context of mutants, recombination can reveal how different mutations interact and whether they can complement each other, which is essential for determining the nature of specific mutants.

Complementation

Complementation refers to the phenomenon where two different mutations in a gene can restore the normal function when present together. This is often tested in genetic studies to determine if two mutants affect the same gene or different genes. If mutant 7 fails to complement other mutants, it suggests that it may be a mutation in the same gene as the others, indicating a shared pathway or function.

Phenotypic Analysis

Phenotypic analysis involves studying the observable traits or characteristics of organisms resulting from the interaction of their genotype with the environment. In this case, the phenotypes of the E. coli strains (r and +) provide insights into the effects of the mutations. Understanding these phenotypes is crucial for interpreting the results of the recombination and complementation tests, as they indicate how mutations manifest in the organism.