Haplogroup U5a1d2 has two branches; U5a1d2a and U5a1d2b. U5a1d2a is more or less exclusively European but U5a1d2b has a much more eastern distribution. U5a1d2b is more or less exclusively found in non Indo Europeans from far eastern Europe and Siberia. It peaks in the Mari of Russia and the Tubular of the Atlai region in Siberia.
Ancient DNA supports the idea U5a1d2b is sometype of far eastern/north Eurasian U5a1 branch. It was relatively common in Siberian Afanasievo, Andronovo, and later in Siberian Sycthians who lived in the same land as modern Tubular. U5a1d2b has also popped up in Comb Ceramic twice, Yamnaya once, and Sarmatians once.
U5a1d2b's strong presence in both Siberian Afanasievo and Siberian Scythian indicates that Scythians had some Afanasievo ancestry.
U5a1d2b's presence in Saami might be able to be explained by Comb Ceramic, considering Sycthians never lived near Scandinavia. And its strong presence in both Volga Russia and Siberia definitely looks like a legacy of the Sycthians.