RootsChat.Com

hi all dont know if im in the correct place but i have a query on ancestry dna. my sister and i have both taken the test and match with the children/grandchildren of 8 siblings of which one is my grandfather. so basically the point is that even though i dont know most of these i have a list passed down and i know 100% that we are connected. during my research over the years i have been in contact with a family called mahan (i am researching mahon) they have matched with my search and after being in touch for 6 months they said they had taken the dna test , so i took one and we matched. i have since matched with all their family who have since taken the dna test. butttt my cousins dont match, not one of them. i have contacted ancestry and because there is at least 30 of my cousins that dont match these people there is not the possibility that the dna has just not been picked up , so there must be a person who is not who we think they are. eg adopted , fathered by someone else etc. but my query is that we are the ones with the name so we must be the right connection but unlikely the  mother would have the middle child to her husband and all the others not . everyone is dead so no one is going to get hurt and also i dont feel its something i would share anyway , but as far as my research goes i thought i had hit the jackpot because it proves the person who i was researching  is correct. its been years of research and now this has thrown a different light on things. can anyone help as i have been looking to find someone on google but looks like no one does this.xx