A study was conducted in an attempt to determine which functional regions of a particular conjugative transfer gene (tra1) are involved in the transfer of plasmid R27 in Salmonella enterica. The R27 plasmid is of significant clinical interest because it is capable of encoding multiple-antibiotic resistance to typhoid fever. To identify functional regions responsible for conjugal transfer, an analysis by Lawley et al. [(2002). J. Bacteriol. 184:2173–2180] was conducted in which particular regions of the tra1 gene were mutated and tested for their impact on conjugation. Shown here is a map of the regions tested and believed to be involved in conjugative transfer of the plasmid. Similar coloring indicates related function. Numbers correspond to each functional region subjected to mutation analysis.
Accompanying the map is a table showing the effects of these mutations on R27 conjugation.
Effects of Mutations in Functional Regions of Transfer Region 1 (tra1) on R27 Conjugation
R27 Mutation in Conjugative Relative Conjugation
Region Transfer Frequency (%)
1 + 100
2 + 100
3 - 0
4 + 100
5 - 0
6 - 0
7 + 12
8 - 0
9 - 0
10 - 0
11 + 13
12 - 0
13 - 0
14 - 0
Which regions appear to have a limited impact on conjugation? <>
5. Genetics of Bacteria and Viruses
Bacterial Conjugation
Struggling with Genetics?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
A F+ bacterial cell can donate DNA to which type of bacterium?
A
An F+ bacteria
B
An F- Bacteria
C
An Hfr Bacteria
D
An R+ bacteria
Verified step by step guidance1
Understand the concept of bacterial conjugation: Bacterial conjugation is a process where genetic material is transferred from one bacterium to another through direct contact.
Identify the role of the F factor: The F factor (fertility factor) is a piece of DNA that allows a bacterium to form a pilus and initiate conjugation. An F+ bacterium contains this F factor.
Determine the recipient bacterium: An F+ bacterium can donate DNA to an F- bacterium, which lacks the F factor. This transfer can convert the F- bacterium into an F+ bacterium.
Consider other bacterial types: An Hfr bacterium has the F factor integrated into its chromosome, allowing it to transfer chromosomal DNA during conjugation. An R+ bacterium is resistant to certain antibiotics, which is unrelated to the F factor.
Conclude the correct recipient: Based on the understanding of conjugation, the correct recipient for DNA donation from an F+ bacterium is an F- bacterium.
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