Marco Molari

@mmolari.bsky.social

110 Followers 116 Following

PostDoc @ Biozentrum - Basel in the group of Richard Neher Interested in microbial genomics, pangenome graphs & evolution 🧬🦠💻

Most events are gain events, associated to the movement of an Insertion sequence.
By comparing presence / absence of sequence with the phylogenetic tree, we can associate junction with gain/loss events.
In the previous scatter-plot we highlight junctions containing insertion sequences, prophages and defense systems. Insertion sequences are present in the majority of junctions, and in particular they explain the high number of 1 kbp junctions. Prophages are present in many hotspots, and also explain the enrichment in 30 kbp junctions. Defense systems are mainly present in hotspots.
scatter-plot of number of different paths and total accessory length for all junctions in the dataset. It shows an enrichment in binary junctions of length 700 bp and 30-40 kbp.
the portion of graph between two subsequent core-blocks is called a junction graph. One can quantify the number of different paths and the amount of accessory sequence in the junction.
Phylogenetic tree with marks on the leaves that show core-genome rearrangements. Most of the events occur on terminal branches, possibly as a consequence of purifying selection.
schematic representation of all observed changes in order of genes in the core genome for the dataset considered.
Schematic representation for a pangenome graph. Edges in the graph represent alignments of homologous portions of the sequences in different genomes. Each genome is a particular walk through the graph.
A core-genome phylogenetic tree for our ST131 dataset.
schematic representation of a phylogenetic tree, with horizontal exchange of genes between different branches of the tree.
Two microbial genomes can be extremely similar on the portions that can be aligned, with less than one mutation every 10000 basepairs, while still retaining a lot of accessory diversity, for example having one non-shared gene every 10.