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Bronn and Jaime in ‘Game of Thrones’

Kent Sepkowitz, MD, is an infectious disease specialist at Memorial Sloan Kettering Cancer Center. Here, Dr. Sepkowitz weighs in on the season finale of “Game of Thrones.”

“Army of the Dead”, this season’s final installment of HBO’s TWX, +0.32%  “Game of Thrones”, covered plenty of ground as we prepare for the long winter of 2017-8 and life without new episodes.

But tucked away in all the plotting and lying and killing and cold weather and slit throats was a gentle story, sure to dominate the final season: a glorious song of incest.

Or, more specifically, of the genetic consequences for offspring when parents are related: Cersei, pregnant again by her brother Jamie, and Daenerys, perhaps pregnant by her perhaps nephew Jon, are making the entire GoT-watching global community worry about the expression of less fit recessive genes unmasked by consanguinity. Right?

Incest, along with cannibalism, is forbidden in just about every society the world over. Not that this was always the case – the Old Testament has many moments when fathers “lay” with their daughters and the like. Of course with Adam and Eve’s offspring, perhaps incest could be forgiven since the pickings were slim, but even Abraham’s generation had some relationships that by today’s standards would be considered statutory rape.

Our current rationale for the incest taboo is placed along Freudian lines – Oedipal urges and Elektra complexes, all of it emphatically not OK. These days, it’s the urge to copulate with family that is the only issue to confront and suppress, not the effects on the gene pool of consanguineal mating.

More likely than a sense of right and wrong or the deep emotions explored by Sigmund and the gang, the real reason that people have moved away from parenting with their blood relatives is related to observations made from animal breeding. Long before Freud entered the scene, farmers and ranchers had been trying to breed a better dog, a better horse, a better cow and a better ear of corn.

Our clever forefathers would find a trait they liked and try to breed for it – maybe a faster gait or a better set of eyes. Or maybe just cuteness and timidity, a dog that likes to sit on a lap all day. These intrepid farmers and ranchers learned pretty quickly that you can push breeding too far. With too much inbreeding, unwanted traits emerge along with that desired great set of eyes. Ah well, science advances in steps and starts.

The great 19th century Moravian farmer-monk, Gregor Mendel (Freud by the way also was a 19th century Moravian by birth), codified our understanding of plant inheritance with his observations on peas shape and color, elucidating the concepts of dominant and recessive genes that are still taught in biology today.

The premise is this: living things have two genes for every trait, one inherited from each parent/progenitor. The struggle for which gene is expressed is conducted according to a fixed set of rules. Some genes are dominant and some recessive. However, when there is no dominant gene (i.e. when each parent provides a recessive gene), an “undesirable” trait can emerge. In this context, undesirability refers to something that compromises the fitness of the next generation. In plants this might be a withered pea; in people, it might be hemophilia.

Even in Westeros, there seems to be a taboo on incest. That said, the Jamie-Cersei conjugation has produced healthy children, though all have been killed. And in truth for a one-off mating, such as theirs, not sustained across the generations Romanoff or Hapsburg-style, the odds are long for double recessives and genetic unfitness.

Renewed interest in incest

Yet the incest-based plot has surely thickened. There is a new incestuous relationship in town, albeit an unwitting connection (but then again Oedipus and Jocasta were unaware and had a nice relationship till the truth came out many years into their marriage). Daenerys Targaryan and Jon Snow finally, after 66 episodes, did the wild thing behind closed doors.

And though Daenerys may be unable to have children, their little twinkle as they discussed this “problem” made a girl and a boy think that the stork may be arriving in Season 8.

So here we are careening into the final season with two possible plot lines in the oven and knowledge that the last time she was confined, Queen Daenerys produced, um, dragons. And that was without a blood relative as dad.

Are NextGen monsters about to spring into the Seven Kingdoms or angry one-eyed giants or maybe just pink little bundles of joy? Who knows how the kids will turn out?

Meantime, we should heed the following advice: forget it, Jake, it’s Westeros.

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