Actually, from genetic studies done, most Xiongnu DNA belong to Tat-C (ie Haplogroup N). The same as the Yakuts.
In Hungary, they dug up graves of Huns, Avars and even ancient Magyars and also found them to be Haplogroup N. But, today, few Hungarians have this Haplogroup N.
Many Uralic and Tatar people in Russia is also Haplogroup N. This haplogroup is also found in 10% of the Anatolian Turks. So, the study might actually indicate a higher Mongoloid paternal contribution in Anatolia if they are willing to include Haplogroup N as a Mongoloid marker (which it undoubtedly is).