Are your DNA connections off?  Do you have DNA matches in which your sibling, aunt, uncle, or first cousin may not have?  Each Person inherits 50 percent of their parents DNA each.  Which copies of DNA you inherit depends on chance and science.  You may have known 3rd cousins not DNA match with you, yet unknown distant cousins in which DNA match with you.  It is possible to lose many copies of DNA as they are passed down generation after generation, but on the flip side, other DNA copies may continue to get passed down generation after generation.