Since consciousness is now thought of as a primary feature of physics, I would suggest that expansion of consciousness beyond the ordinary—through shamanic journeying/trance—does influence our psycho-spiritual evolution. If then, our thoughts, feelings, beliefs and experiences are integral aspects of the epigenetic field that influences how our genetic material expresses itself, (Lipton, Bruce, Ph.D.; The Biology of Belief ) then shamanic practice can indeed effect physical changes as it works to alter all of those aspects.
Furthermore, while these changes are to the phenotype, there is ongoing research exploring whether changes in the phenotype can also affect the genotype.
This conclusion from the article, “Phenotypic plasticity in development and evolution: facts and concepts” by Guiseppe Fusco and Alessandro Minelli, gives a sense of that exciting work:
“It has been argued that genetic accommodation in the strict sense refers to nothing but standard evolutionary change of genotype frequencies by selection, after mutational or environmental changes have uncovered previously cryptic genetic variation. Thus, the phenomena of phenotypic plasticity in evolution can be easily reduced to standard evolutionary genetic processes (see discussion in Braendle & Flatt 2006; Pigliucci et al. 2006).
We think that this argument ignores a growing mass of data on the pervasiveness of plasticity phenomena at all levels of biological organization and on inheritable (selectable) epigenetic variation (Gilbert & Epel 2009; Love 2010). Beyond that, the (non-warranted) possibility to reduce a set of well-distinct phenomena to the interplay of a smaller number of more basic processes does not imply that such a reduction is useful per se. In this case, disregarding plasticity phenomena, the explanatory power of a theory of the origin of phenotypic variation would be tangibly reduced, with obvious consequences on the structure of the evolutionary theory as a whole.
Even from this rapid excursion into development and evolution of phenotypic plasticity, it should be apparent that the scope for its inclusion in the mainstream evolutionary theory is enormous. However, it is still more evident that currently we have only a shallow knowledge of the complexity of the interrelations between different processes of phenotype determination and their evolutionary consequences. We have only just started.”
As to the “gifted shaman,” I see that as a shaman who is complete in their integration of the ordinary and non-ordinary experience, as well as one who maintains strong relationships with the seen and unseen influences over reality for the purpose of negotiating harmony.