This is a very interesting leap that opens up new possibilities for Sam's Locus of Control.
We are given the concept that Sam was able to leap very much outside his own lifetime here, the Civil War in the 1800's because the leapee is his own great grandfather. This is debatable for two reasons.
1.) On Average we share 12.3% of our DNA with our great grandparents but it's more likely less than that due to the random nature of DNA swapping during recombination which can result in giving us more from one set of parents, grandparents etc. than the other.
So though I am unsure for certain, it seems probable to me that the chances of PQL being able to pick out pieces matching Captain John Beckett in Sam's DNA are slim to none because they wouldn't have a strong presence. So that test would have been more believable coming out as inconclusive.
Source:
http://genetics.thetech.org/ask/ask445
One could also wonder where they managed to obtain a sample of Sam's DNA. While the novels use the notion that he and Al's connection in the imaging chamber is established from their having contributed brain/nerve cells to Ziggy (And it IS established that Sam and Al have the
strongest connection to each other when Gooshie was unable to connect as clearly in
Killin' Time), that's never discussed in the show.
2.) When it's established in
Mirror Image that Sam can take control of his leaping based on what he believed he could do, the possibility that he could will himself outside his lifetime was opened up. This notion and with the match between Sam and Captain John Beckett's DNA being possibly unfindable, who knows? There's no clear motive for it but perhaps somewhere in his mind while he was leaping out of
The Misfits set (
Goodbye Norma Jean) he could have entertained the possibility/desire and willed it to him.
Alright taking a break from the intellectualness, Sam's reaction to Olivia Covington being his Great Grandmother/Captain John Beckett's future wife was priceless! Olivia Covington was certainly a stubborn, no-nonsense woman but also quite strong and independent for her time. Feminism in America was just beginning with the first movement having been in 1848 and being widowed had motivated her to stand up and defend herself and her home rather than being anxious to re-marry.
Since Sam's great grandparents successful descended into himself and his siblings and Isaac had to continue the line leading to Martin Luther King Jr, it was unclear what he was there to do but my best guess was for the slave family that Isaac was hiding. It's believable which I appreciate amongst all these somewhat gimmick like elements and again we revisit Sam's control over the leaps. Another angle there is that a lot of the time he himself may be deciding what the wrong in the situation he's placed in is and thus to make it his focus. Notice how most of the time when he pits his gut against Ziggy it always wins (not exactly the fairest match since a computer can't have gut feelings but still). Here helping that slave family is what he was set on doing. He'd decided on that mission before being told to do anything.
This is a possibility also present in
The Leap Back which also supports Sam's ability to will himself to further back before his lifetime. He explains that he can leap into 1945 to save Al because the simul-Leap gave them pieces of each other and thus part of him was Al. Another option however is that it was the will to save Al's life, that same will to save the life of a loved one that had pretty clearly led him to the BRAVO squad in
...Vietnam.
Sam being more technical than spiritual in his beliefs however, not to mention having inherited plenty of his father's stubbornness would of course only look at it from the scientific perspective. He's presented as being more comfortable what could be proven, what he found to be the most logical.
Let's go back to Isaac. We remember that actor in a lesser role in season 1's
Color of Truth as Jesse Tyler's son Willis Tyler but this one was a lot stronger. The expression of seriousness that he always had was very powerful and a lot of his character actually resembled his descendent, MLK.
In fact Olivia's loyalty to Isaac thus her sympathy for blacks and her stubbornness are all traits that Sam, her great grandson shares with her. So there is another reason that their DNA test shouldn't have been so easy, it seems Sam may share more with Olivia than with Captain John. Interesting Al didn't pick up on that from her attitude, that's a conversation I would have enjoyed haha!
Overall, a good episode.
