The tune used for Yom Tov Kiddush throughout the year by most Ashkenazim is almost exactly like the tune used for Akdamut - the Aramaic poem recited in many Nusach Ashkenaz and Nusach Sefard synagogues just prior to reading the Torah on the 1st day of Shavu'ot, and the "reshuyot" for Chatanei Torah and Breishit on Simchat Torah (Thanks to DoubleAA for pointing tout the Reshuyot).
Is there any relationship between kiddush and these other items that historically have them use the same tunes?