design: Sample preparation. Bacterial genomic DNA was purified from pools P0, P1, P2, P3 and P4 by using the DNeasy Blood and Tissue Kit (Qiagen, 69506) following manufacturers instructions. Sample purity, quality and concentration were measured by Nanodrop, agarose gel electrophoresis, and Qubit fluorometry. Purified genomic DNA was used as a template for a two-step PCR protocol to generate ~1.2 Kb amplicons encompassing the hmw1A 5-UTR SSR region. To do so, the hmw1A 5-UTR regions were amplified in a first-round PCR performed using KAPA HiFi HotStart ReadyMix PCR kit (Roche, KK2602) and specific primers Forward 5-block-M13 and Reverse 5-block-M13 designed following the PacBio guidelines (PN 101-921-300 REV03 MAR2023). Generated amplicons were used for PacBio-SMRTbell 3.0. sequencing. SMRTbell libraries were prepared following the PacBio guidelines Procedures and Checklist-Preparing multiplexed amplicon libraries using PacBio barcoded M13 primers and SMRTbell prep kit 3.0 (https://pacbio.cn/wp-content/uploads/Procedure-checklist-Preparing-SMRTbell-libraries-using-PacBio-barcoded-M13-primers-for-multiplex-SMRT-sequencing.pdf). Analysis of PacBio-SMRTbell 3.0. amplicon sequencing. Demultiplexed circular consensus sequences in fastq format were filtered to those between 900 and 1,500 nucleotides and converted to fasta using seqkit (https://bioinf.shenwei.me/seqkit/), followed by processing through Tandem Repeats Finder (TRF) to identify tandem repeats up to a unit size of 15. Single reads were passed to TRF using the following parameters: trf - 2 7 7 80 10 50 15 -h -ngs. Subsequent parsing filtered for reads containing heptameric repeats with sequences consistent with that expected for each genotype; circularly permuted repeat units identified by TRF were considered valid for heptamer filtering. Although TRF usually reported integer values for SSR copy number on individual reads, it also sometimes reported fractional values due to both similarity to the repeat in flanking base pairs, as well as contributions from indel errors. Plots used values binned to the nearest integer.