The Borjigids had a legend that after the death of Dobun-mergen, the alleged ancestress, Alan-ko, bore Bodunchar after being visited by a strange 'golden glittering man'. Rashid ad-Din provided this rumor by alluding to a foreign origin of the visitor and described him as having red hair and blue-green eyes. Researcher Paul Ratchnevsky speculates that the mysterious visitor could be a Kirghiz since the Kirghiz people were said to be tall and possess red hair and green eyes. He further speculated that in contrast with the red-haired Kirghiz, Chinese Tangshu had said those nomads with black hair were descendants of a Chinese general called Li Ling who surrendered to the Huns.
Genghis Khan is a descendant of Bodunchar, and therefore thought to also have red hair and green eyes. When Genghis Khan's father died, his tribesmen deserted him for the Tayichi'ut clan, a sub-clan descending from Kabul Khan. Timuchin, aka Genghis Khan, was taken custody by the Tayichi'uts. He ran away from the Tayichi'ut clan, and he was rescued by a Tayichi'ut man who had two sons and one daughter.
The younger son of the Tayichi'ut man was called Chi-lao-wen, one of the four pals of Genghis Khan in his later campaigns. The daughter of the Tayichi'ut man was later married to Genghis Khan. So, after mixing with another tribe, the genes receded most likely.