Interaction between Conjugative and Retrotransposable Elements in Horizontal Gene Transfer
Figure 4
Mapping of retrotransposition events along L. lactis chromosome.
(A) Mapping of sites. Randomly sampled libraries of the reads for D-C, D-pRS01 and D-pLtrB were mapped along the L. lactis IL1403 chromosome [25]. For sequences see Tables S2–S4 in Text S1. The relative retrotransposition frequencies are represented by vertical bars: black, D-C strain without relaxase; blue, D-pRS01 and D-pLtrB strains with relaxase. The average number of unique chromosomal insertion points in randomly sampled libraries and the total number of unique chromosomal insertion points in the libraries are shown by spheres (right) with the area of each sphere corresponding to the value indicated. The putative location of Ter is shown by arrow [25]. (B) High density of the events. The locus ∼60 Kbp upstream of the putative Ter is shown in details. Multiple retrotransposition events were observed in the D-pLtrB strain (blue) and less in control strain D-C (black). The als and cit loci have had the highest density of events in the D-pLtrB strain, while only a few were identified in control strain D-C.