Can we assume that the term “interdimensional DNA” is just a metaphor representing the ability to generate end products, analogous to the gene expression function of physical DNA to make proteins in living cells?

This is quite correct. It is handy because it is a short acronym but clearly one that puts it into a different class, being interdimensional. And while not comprised of the same molecular construction of nucleotides in physical DNA, in an energetic sense it is a parallel wave of varied signal that is ideally suited to convey information much in the way the nucleotide sequence of DNA determines what a portion of the DNA, termed a gene, will express to ultimately make a discrete protein substance that has a physiologic role of some kind. In the case of interdimensional DNA, it is conveying a soul attribute and the instructions for it to be instilled or strengthened or modified in some respects within the makeup of the human extension undergoing an incarnation. The complete reconfiguration of soul attributes does not happen until the stage where the soul connects to the fetus. And that is when there is much readjustment in realignment of things to configure the being prior to launch, so to speak, so it will be fully equipped with all the human attributes intended to be available and on display for many anticipated needs and future roles in life. This is very analogous to the growth of the embryo into a fetus, where the germline cells with their pluripotential genetic content give rise to a myriad of cells and tissues of complex architecture and design capable of many, many important and essential functions that will be needed by the body. So an infant can be birthed and remain living an independent existence with autonomy, having all the onboard necessities to thrive. So while the bodily architecture and physical foundation can be traced back to the genetic predisposition, it is only part of the story because much of that organization is imposed by the morphogenetic field. And that is influenced, in part, by the soul destined to inhabit the infant and complete the picture. This is an important missing link still unappreciated by science or metaphysics, that the morphogenetic field of the human being arises from the soul. Those other life forms that are not an extension of a discrete soul have a collective oversoul that provides a parallel morphogenetic field for the collective of organisms. So mechanistically, they are comparable, but those organisms having a discrete soul have a more demanding and advanced role in life and require more intricate components and capabilities. And because they are discrete beings designed to all be different and thus have a unique soul signature and composition with respect to countless attributes, the morphogenetic field will have unique aspects as well. So this is how certain attributes traceable to ancestral lineage but not immediately obvious in how that can be explained through genetic inheritance alone are nonetheless expressed. Things like having scars on the body at a location of a past-life fatal wound, or birth defects, or deformities that are not traceable to a genetic alteration per se. This is also true of aspects of the appearance and stature to some extent as well. So interdimensional DNA, indeed, has a quite profound role and influence on things at all levels of the being, including the soul itself. It provides a means for feedback via life experience that will influence the soul directly and add to learning and growth, and in some cases wounds that will need healing attention and a karmic rebalancing in order to recover.