In recombination studies of the rII locus in phage T4, what is the significance of the value determined by calculating phage growth in the K12 versus the B strains of E. coli following simultaneous infection in E. coli B? Which value is always greater?

Verified step by step guidance

1. Understand the context: The rII locus in phage T4 is used to study genetic recombination. Phage T4 can infect different strains of E. coli, such as K12 and B.
2. Identify the experimental setup: Phage T4 is used to infect E. coli B, and the resulting phages are then tested for their ability to grow on E. coli K12 and E. coli B.
3. Recognize the significance of the strains: E. coli B allows for the growth of all phage types, while E. coli K12 only allows growth of recombinant phages that have restored the wild-type function at the rII locus.
4. Determine the values: The number of plaques (areas of phage growth) on E. coli B represents the total number of phages, while the number of plaques on E. coli K12 represents the number of recombinant phages.
5. Conclude which value is greater: The number of plaques on E. coli B is always greater than or equal to the number of plaques on E. coli K12, as E. coli B supports the growth of both recombinant and non-recombinant phages.

Key Concepts

Recombination in Genetics

Recombination is a genetic process where genetic material is exchanged between different chromosomes or within the same chromosome. In the context of phage T4, recombination studies help understand how genetic variation occurs and how traits are inherited. This process is crucial for mapping genetic loci, such as the rII locus, and determining the genetic distance between them.

Phage Growth in Bacterial Strains

Phage growth refers to the replication and proliferation of bacteriophages, which are viruses that infect bacteria. In this study, the growth of phage T4 in different strains of E. coli (K12 and B) is analyzed to assess the efficiency of infection and recombination. The comparison of phage growth in these strains provides insights into the genetic compatibility and the effects of host factors on phage replication.

Simultaneous Infection and Its Implications

Simultaneous infection occurs when multiple phages infect a single bacterial cell at the same time. This method is significant in recombination studies as it allows researchers to observe the interactions between different phage genotypes and their potential to recombine. Typically, the value representing phage growth in the K12 strain is greater than that in the B strain, indicating a higher efficiency of recombination or infection in the K12 background.