Excellent and astute series of replies. Thanks for sharing.
They refer to the human sequence the bacteria has acquired as an “element”. This usually denotes a sequence of DNA that is bound by a specific 3-D protein, usually a transcription activator or repressor.
For example, the difference between lactose tolerance as an adult and lactose intolerance is a mutation in a transcription repressor ‘element’ near the lactose gene. In almost all mammals this repressor turns off the gene in adulthood, in Northern European populations and some African cattle herding populations this DNA ‘element’ is mutated, so that the lactose gene is expressed as an adult.
It will be interesting to see what, if anything, this DNA is doing, and what advantage (if any) it confers upon those bacteria with it.