Ethics The work reported on TwinsUK samples was carried out with informed consent under TwinsUK BioBank ethics, approved by the North West–Liverpool Central Research Ethics Committee (REC reference 19/NW/0187), IRAS ID 258513 and earlier approvals granted to TwinsUK by the St Thomas’ Hospital Research Ethics Committee, later the London–Westminster Research Ethics Committee (REC reference EC04/015).
RNA sequencing and analysis E. coli BL21(DE3) cells (NEB: C2527H), which lack endogenous copies of IS621 elements, were transformed with plasmids encoding either the RE–LE junction or the LE–recombinase–RE region of the IS621 element. The cells were plated on LB (lysogeny broth) agar with kanamycin and grown overnight at 37 °C. Colonies were scraped from the
