First of all I loooooooved this episode.
But while Fringe has recaptivated me, it hasn't managed to get me to suspend my disbelief like it used to. Theoretical Physics is NOT my bag. Heck, I struggled with mechanical physics. Also, I'm decidedly unable to think about these things long enough to form a cohesive theory in my brain....it all swirls around. So my posts are always pretty vague.
Which is why I miss the biological sci-fi. Full disclosure: I was a bio major. I love bio. But I really love sci-fi, too. I feel the same way about sci-fi as I do about English. You need to know the rules before you break the rules. I end sentences with prepositions, break up my sentences, and capitalize common nouns for emphasis in casual writing. It's sort of like how you have to take basic English classes in a creative writing program.
Well, I feel like the writers have given up an even trying to do well by the science of the show. Anyway, I felt as though the points about DNA were glossed over. There wasn't enough detail in Walter's explanation of the polyploidy (of course, too much detail can be detrimental to suspending belief, but I'd like an indication that there is an explanation in the Fringeverse, even if Walter or the audience hasn't encountered it yet). Chromosomes are physical matter. So why would that part of the alternates (I'm assuming from other timelines...if we are to make a distinction between timelines and universes...and yes I think that Peter's absence could have a butterfly effect large enough to affect so many lives, even though I don't think it has to be one specific alternate timeline in question) be crossed over? What happened to the alternates'?
I think one of the ways to rectify this situation is that by giving DNA some superpower. We've already entered the spiritual realm on Fringe. There has been heavy flirtation with religious allegories and divinity. DNA seems to be different on this show than the way we understand it in our own (not blueveres, but boring old RL) universe.
-Walter presented an infinite universe model in Season 1. As far as I understand it, choices are important to those branching, because Walter says so. But there is also randomness to the universe, not to mention a bit of entropy. Throw in the fact that unless Fringe is The Matrix Re-Redux, our choices and timelines do not exist in a vacuum (well, except Peter's).
-I've touched upon this elsewhere: What is absolutely hardest thing for me to accept about these two universes, in my opinion, is that (with possible exemptions on Ella and the couple in 6B), we have genetic doppelgangers. So not only to the same people happen to procreate across the world(s), but that practically indistinguishable genes are passed down. Looking at our own world, had my parents conceived me at any other moment, I could be as different from myself as I am from my brother, genotypically.
-Genetic material alone cannot be the common thread between universes. There has to be some drivel about the human spirit of course, as Professor Farnsworth would say. There is a great genetic imbalance between the Red and Blue verse. Entire species of livestock are missing. The differences in communicable disease stats reflect an imbalance between the genetic code of viruses and bacteria. And so there must be something to human DNA that sets it apart from other DNA.
-This is how I reconcile the soul magnet subplot with Fringe overall. I imagine that these universes, the Red and Blue, before the bridge, have been snapped together in a weird 3.5 dimensional way using doppelgangers as anchor points. Also, DNA is involved in the machine's code. Supernatural DNA could help explain the quantum entanglement of humans as whole beings instead of pieces of matter (still not sure how this effects microorganisms that are integral to our bodies with different DNA).
Anyway, I didn't find anything particularly wrong with the way DNA was written into this episode. But I didn't feel as though the writers had a clear idea what they were withholding from us. Nor did they throw in any bones on medical oddities: tetraploidy has occured in a few live births before. C'mon Walter, you should know that!