1). Siblings can have different DNA results from each other!
Something that I hear often is, “My sister/brother can do the DNA test for all of us,” the assumption being that if one sibling does a DNA test, the rest of the siblings don’t need to because the results will be the same. This assumption is not true.
Siblings share about 50% of their DNA with each other. Each individual gets 50% of their DNA from Mom and 50% from Dad, but what genes are passed down is what creates the differences. Which genes you get from which parent is random, like a dice game. Using this same analogy, though the dice you are using stays the same (the amount you inherit from mom & dad), the results each time you roll them may be different (what specific genes you inherit). While one sibling may inherit a lot of Mom’s Irish and only a bit of her Swiss, the other sibling may get more Swiss and less Irish. For visual learners, this bead example explains it very well.
It also effects how you match with cousins. One sibling may be a stronger match to a particular cousin and if they are very distant, this could make a difference in terms of which matches show up and which don’t. One sibling may match a distant cousin while the other sibling may not show up in that cousin’s match list at all.
An example from my own tree: I have 2 cousins who are siblings in my DNA matches list. They both showed up with 41% Germanic Europe…and then their results diverged. Jack had 18% England/Wales/NW Europe ancestry to Jill’s 26% and 11% Ireland/Scotland to her 16%. Even more surprisingly, Jack’s results showed 8% Italian while Jill has 0%. I also match Jack differently at 27 centimorgans across 4 DNA segments than I do with Jill at 41 centimorgans across 5 DNA segments. Had Jill just relied on Jack’s DNA results and assumed hers would be the same, she may never have known that she inherited more English/Irish/Scottish DNA than he did and none of the Italian (according to this particular test).
So, long story short, please don’t assume that if a sibling has tested, you don’t need to. You could be missing out on some interesting information about yourself!
2). Fitz in front of a surname means something!
You may see the surname FitzHerbert, FitzJohn, etc. in your family tree research, typically if you are researching old English (specifically Norman – the origins of this trend are described here) ancestry. Fitz means “son of” (though it was given to sons and daughters) so if you have an ancestor named John FitzWilliam, you can assume that John’s father’s name was William. It’s a useful thing to know if you have run into a pretty sturdy brick wall regarding John FitzWilliam’s parentage. Having a surname like FitzWilliam, you can at least assume what John’s father’s first name is, if not his mother’s. To our current surname standards, we might assume that John FitzWilliam’s father William’s full name would be William FitzWilliam. Nope. Use the same naming tradition. Because William’s father’s name was Lionel, William’s full name is actually William FitzLionel.
Another fun Fitz, that is similar but not quite, is the surname of FitzRoy. Unlike the previous example, it does not mean that John FitzRoy’s father’s name was Roy (or I guess it could, but I haven’t come across many Roys in medieval history); it actually means he was the son (or daughter, if she happened to be Jane FitzRoy) of the king. This is often seen in illegitimate children of the king who were given this surname as public acknowledgement of their connection. King Henry VIII’s illegitimate son Henry FitzRoy (by his mistress Elizabeth “Bessie” Blount) is a famous example of this trend in action.
3). Christopher Guest and Jamie Lee Curtis are members of the Nobility!
This is one of my very favorite fun facts, mostly because every time I think of it I can’t help but imagine Nigel Tufnel being presented to the queen and making a mess of it. Yes, beloved comedic actor Christopher Guest of This is Spinal Tap! and Best in Show fame is actually Christopher Haden-Guest, 5th Baron Haden-Guest, making him Lord Haden-Guest in polite company. Actress Jamie Lee Curtis, already known as the “scream queen” for her roles in Halloween and other horror movies and “royal” by Hollywood’s standards for her double whammy parentage of classic greats Tony Curtis and Janet Leigh, is actually Baroness Haden-Guest by her marriage to Christopher Guest. The title was created in 1950 for Guest’s grandfather Leslie Haden-Guest and passed to 2 uncles then Guest’s father before landing on him. I may be the only person I know who is terribly thrilled with this piece of trivia, but I will say it certainly makes watching This is Spinal Tap! and Halloween more fun!
Genes are like Beads: https://genetics.thetech.org/ask-a-geneticist/same-parents-different-ancestry
Origins of Fitz: https://en.wikipedia.org/wiki/Fitz
Baron Haden-Guest information: http://www.cracroftspeerage.co.uk/online/content/hadenguest1950.htm