My theory all along has been that the Uzumaki Clan migrated to Konoha when 1st Hokage founded it. That is why the 2nd knew Water Techniques so well.

So it would be like this for the generations........

1st Hokage - Uzumaki Refugees

Tsunade's Parent - 2nd Hokage

Tsunade - Jiraiya

Tsunade and Jiraiya are the parents of Yondaime

Yondaime is the father of Naruto.