I got Ernesto and Mimosa from a farm and there I saw their siblings and their mom. One sibling got adopted out too, one of them died. I saw their mom and last remaining sister with her kittens during a return visit, but sadly they are all dead now, that farm was a dangerous place for cats.
Flynn and dEUS have a pedigree, I have met Flynn's father and mother and have been to several catteries that have bred and still own cats that are in his pedigree.
During a show the breeder of Flynn's grandmother came to his cage to take a look at him and became very emotional (she cried) because he is the spitting image of his grandma who she had to rehome.
There is even a member of this site who had a Somali (I looked him up just now and was very sorry to read he is deceased

) that I could connect with mine, even though we are on different continents.
I have not made an in depth study of dEUS' ancestors, his father was imported from Norway so that makes it a bit more complicated.
In 2006 I did see a relative from his father's side on the fife world show that was held in my country that year.
I have become good friends with dEUS' breeder and through her I have been able to follow all his siblings and their offspring, I've gotten to know several breeders and kittenbuyers who own his halfbrothers/sisters, nieces, nephews, cousins and their offspring.
I try to keep tabs of my cat's family so I might be able to buy a cat from the same lines if I ever buy another Birman or Somali. It is also useful to know if there are any health problems or deaths in the family.