I haven't had time to read the full paper, but I am wondering which SNP's the author tested. It seems that he is using a rather antiquated phylogeny, still referring to C3 for C-M217, a nomenclature last seen in the 2013 ISOGG tree. Since 2014 it's been called C2. If so, that K* could really be K2b2a, which is the same as
haplogroup P1 (M45). This P1 is common from Mongolia to Northeast Siberia, and is found at lower frequencies in the Caucasus, Iran, India, Tibet and Southeast Asia.
Haplogroup P1 was found in Early Neolithic Iran (8000-7700 BCE) by Lazaridis at al. 2016. Since the oldest clades of P1 are found around the Caucasus and Iran, and that these K (P1?) tribes seem to be the ones who brought pottery to the Lake Baikal region, I would think that they originated around the Caucasus or Iran. Annoyingly some mtDNA samples are just listed as others, with no indication of what they could be. I wouldn't be surprised to find mt-haplogroup HV, N1a, N1b, W and/or X, which are all found in modern Altaians and Caucasians alike.