Are there any unexpected karmic consequences from wet-nursing an infant as a result of possible DNA transfer from the wet nurse to the baby, and is this of any significance?

This again is minor. The physical proximity and the gifting of the breast milk is perceived as a major act of nurturing, but will not have the same emotional significance to the infant as being with the natural mother, assuming a relationship was established at some point prior to the introduction of the wet nurse. An initial bonding at birth will continue to support the relationship even in the absence of breastfeeding. There is an awareness of the infant that the emotions are not the same coming from the wet nurse even though milk is being provided. It is the association of the act of nursing with the loving consciousness felt by the mother that creates a powerful association between the two, and that is a more important stimulus than the nutritional liquid being ingested in and of itself can provide. In addition, the love imparted to breast milk by a mother, a biological mother of the infant, will be an added enhancement to the experience, whereas a wet nurse will not have the same energy being conveyed and so the milk will be less of an influence on the infant as a consequence. While there is DNA exposure, it is of a relatively minor degree. There is much degradation that happens with things ingested in food, so very little DNA will actually be absorbed within the body in a way that can impinge on the cells and tissues. Most is degraded and becomes inconsequential as a potential factor.