Were there Chinese in the army of Genghis Khan in Russia?

I did some genetic research and met one Russian guy who had the same Y chromosome haplotype (O3) as me. He is as white as any white person you meet and I am 100% Chinese. Y chromosomes are only ped on from father to son. More than 80% of the billion Chinese have Hap. O. How did a Russian dude end up with a typically Chinese gene? I later read that Genghis Khan and his grandsons had employed Chinese siege engineers and foot soldiers to scale walled castles of Europe and the Middle East. Later during the Mongol rule of Russia and Persia, some Chinese merchants made their living in those lands. Many of them never returned to China. Presumably they intermarried with locals. In the Tatar quarter of the Russian city of Novgorod, they found a couple Chinese settlements of merchants. Russians also have a genetic trait that doesn't enable them to tolerate alcohol as well as other Europeans. Thus, they are more like Asians and Native Americans in this regard. People mixed