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Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
All textbooksSanders 3rd EditionCh. 6 - Genetic Analysis and Mapping in Bacteria and BacteriophagesProblem 1b
Chapter 6, Problem 1b

For bacteria that are F⁺, Hfr, F', and F⁻ perform or answer the following.
Which of these cells are donors? Which is the recipient?

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1
Understand the definitions of the bacterial types: F⁺ cells contain the F (fertility) plasmid, which allows them to form a pilus and transfer genetic material. Hfr (high-frequency recombination) cells have the F plasmid integrated into their chromosome, enabling them to transfer chromosomal genes during conjugation. F' cells have the F plasmid but also carry some chromosomal genes due to improper excision of the plasmid. F⁻ cells lack the F plasmid and cannot initiate conjugation.
Determine which cells are donors: F⁺, Hfr, and F' cells are considered donors because they have the ability to transfer genetic material to other cells. F⁺ cells transfer the F plasmid, Hfr cells transfer chromosomal genes, and F' cells transfer the F plasmid along with additional chromosomal genes.
Identify the recipient: F⁻ cells are recipients because they lack the F plasmid and cannot initiate conjugation. They can, however, receive genetic material from donor cells.
Summarize the roles: F⁺, Hfr, and F' cells are donors, while F⁻ cells are recipients in bacterial conjugation.
Conclude by noting the significance: The ability of these cells to act as donors or recipients is crucial for horizontal gene transfer, which contributes to genetic diversity and the spread of traits such as antibiotic resistance in bacterial populations.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Fertility Factor (F)

The fertility factor (F) is a plasmid that enables bacteria to initiate conjugation, a process of genetic exchange. Bacteria containing the F plasmid (F⁺) can act as donors, transferring genetic material to recipient cells. The presence of the F factor is crucial for determining the roles of bacterial cells in conjugation.
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F Factor and Hfr

Hfr Strains

Hfr (high frequency of recombination) strains are bacteria where the F plasmid is integrated into the chromosomal DNA. These strains can donate chromosomal genes during conjugation, making them effective donors. The integration allows for the transfer of larger segments of genetic material compared to F⁺ cells.
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F Factor and Hfr

F' Strains

F' (F prime) strains are derived from Hfr strains when the F plasmid excises from the chromosome, sometimes carrying adjacent chromosomal genes. These strains can also act as donors, transferring both the F plasmid and additional genes to recipient cells. In contrast, F⁻ cells lack the F plasmid and are always recipients in conjugation.
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Related Practice
Textbook Question

Match each statement (a–e) with the best answer from the following list: consultand, 50%, prior probability, 66.7%, obligate carrier, 100%.

The Mendelian risk that a person is a heterozygous carrier of a recessive condition

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Textbook Question

Match each statement (a–e) with the best answer from the following list: consultand, 50%, prior probability, 66.7%, obligate carrier, 100%.

The probability that the healthy brother of a woman with an autosomal recessive condition is a heterozygous carrier

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Textbook Question

For bacteria that are F⁺, Hfr, F', and F⁻ perform or answer the following.

Describe the state of the F factor.

Textbook Question

For bacteria that are F⁺, Hfr, F', and F⁻ perform or answer the following.

Which of these donors can convert exconjugants to a donor state?

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Textbook Question

For bacteria that are F⁺, Hfr, F', and F⁻, perform or answer the following.

Which of these donors can transfer a donor gene to exconjugants?

Textbook Question

For bacteria that are F⁺, Hfr, F', and F⁻, perform or answer the following.

Describe the results of conjugation (i.e., changes in the recipient and the exconjugant) that allow detection of the state of the F factor in a donor strain.