I used to tell my high school Biology students ‘wild’ stories about the genetic research of the early 2000’s (so long ago!) I always felt as if I had to be extra animated because I was sure I sounded like a crackpot!
I would wave my arms and spit and spew while telling them about the control researchers are gaining over the tools of heredity and how it is almost impossible to imagine where that will lead. There will probably be a day (no so far off now, either) where a genetic counselor will sit you down in front of a computer monitor – or more likely, hand you the latest version of an I-Pad – and ask you “Okay, now... what color would you like his hair to be? – or did you say you wanted a little girl?”
I have thought some about this…
We’re taught (insect) evolution is, basically, a series of trade-offs. One particular characteristic is sacrificed for the sake of another that makes individuals more competitive. For example, Madagascar Hissing Cockroaches (Gromphadorhina portentosa) remain wingless their entire lives. They are a present-day exception to the “insects have four wings as adults” rule. Evolutionary biologists tell us these cockroaches’ ancestors had wings! And nearly all other species of cockroaches also have wings.
As the story goes… when Madagascar broke off the eastern coast of Africa, it harbored a subset of the resident plants and animals that lived in that part of the continent. While these organisms had all evolved together on the mainland, not all of them got stuck on the newly formed island. This, along with special, climatic and geographical differences, meant Madagascar represented an entirely different habitat with entirely different challenges (or, selective pressures). The course of evolutionary change changed.
When banished to the island, the ancestors of Madagascar Hissing Cockroaches probably didn’t hiss, and instead flew to escape predators. For the Hissers’ progenitors the initial evolutionary epiphany probably came from learning that they could simply run from the predators that survived the isolation. Not flying saved energy, too. So the historical Cockroaches got real good at running away first. Running away was probably more effective if you could slither through small crevasses in rocks or wood. Wings could severely hamper that ability and so they probably became more reduced over time. Soon, the Cockroaches born without wings altogether could not only more effectively flee, but also saved the metamorphic resources and could presumably produce more offspring! (This is an example of a plausible evolutionary story – and allows us to develop measurable questions.)
Here is the important part… making wings requires biological resources and energy. When wings help you survive long enough to reproduce – and simply running doesn’t – it is worth a great cost to make wings. When there is no advantage to flying, why waste the resources? To some extent, at this level, everything is a ‘cost and benefit’ analysis. Sooner or later, resources or energy run out and the individual is not as productive.
Resources and energy are limited.
And as we crash headlong into the exciting frontiers of making life the way we want it, we should remember limiting factors. You can’t have everything – where would you put it!?
Whatever we wish to ‘create’ out of "Life’s Legos," the potential for unintended consequences is enormous. I have always thought it would be possible (and perhaps a good idea… though perhaps not) to make humans photosynthetic – at least in part. Like, we could have green noses and when feeling peckish, we could step outside and look to the sky! But at what cost… Would we cover our green noses except when eating – maybe only in private – use the sunroom before the restroom? Of course, there would be some biological cost, too. It takes a lot to make sugars with the Sun’s energy – we would surely have to give up something – maybe teeth!
In our never-ending pursuit of immortality, many new genetic engineering initiatives target longer life. It seems likely an entire suite of diseases, including cancer and AIDS, will be rendered trivial in the face of the power of these tools. So, every cancer patient thrives, failing vital organs can be replaced with copies made from your own tissues, ALS disease, Diabetes, obesity, and a huge range of human ailments will be mused about along with stories of the Black Plague and Smallpox.
Imagine – everyone lives forever!
Of course, ask any ecologist and he or she will tell you that overpopulation is the biggest threat to our continued comfort level on Earth (such that it is now). Unintended consequences?
It isn’t that we shouldn’t rise to these amazing challenges and opportunities. It’s that we should really think as a culture – actually, as many cultures – what this will mean to what is humanity.
The title for this essay is a quote** in a Reuters article about an amazing – truly amazing – technique developed to cure a congenital disorder that affects one in 65,000 children. It is passed on to offspring through the mother’s mitochondria. Mitochondria are the organelles in our cells that, in a process opposite to photosynthesis, extract (the Sun’s) energy from the sugars we eat. This requires a very complex set of chemical reactions that need special enzymes and other proteins, so it has its own set of genetic instructions, the mitochondrial DNA.
Since this DNA isn’t in the cell’s nucleus, it doesn't get mixed with the father’s genes during fertilization. It gets passed on from the mother mostly intact. (The father has mitochondrial DNA, too – that he got from his mother – but his mitochondria don’t get passed to his babies.) This has proven to be a very important concept for heredity studies. Genetic lineages are sometimes hard to follow because of the mixing of traits during sexual reproduction. Mitochondria get passed along independent of this mixing. The famous story of Lucy, the first “mother of all mankind,” was revealed through mitochondrial DNA. But mitochondrial DNA can mutate also, and the changes are all passed on from the mother.
The researchers in the Reuters article removed the fertilized nucleus (containing DNA from the mother and the father) of an egg cell from a woman who was known to have damaged DNA in her mitochondrial genome, and placed it into the emptied nucleus of a woman whose mitochondria were normal. So, the resulting baby would have a combination of the mother’s and father’s genes, and the mitochondrial DNA of another woman. So the child has, essentially, three parents.
Is it okay to do that?
Well, if you ask me, it begs for unintended consequences. The current state of genetic engineering research is so exciting – but still woefully incomplete. Much like the ‘dark matter’ of cosmic physics, ‘junk DNA’ is being found to be anything but junk. Of course, it isn’t completely clear what it is, either! And did you know there are now 6 different kinds of RNA – not the three you learned about in biology class (if you got that far!) We don't even know what we don't know.
The Rueters article repeatedly states that the child will actually only reflect the genetic makeup of the mother and father – since the DNA in the donor’s mitochondria doesn’t contribute to the offspring’s makeup. This sounds to me like a “famous last words” claim. What could go wrong?! Can’t miss!
As we delve into this incredible, fascinating, powerful and a little frightening, new realm of controlling creation, I think we have a tall order to make sure we know what we’re doing – at least to some extent.
In past posts, I have referred to the Star Trek characters The Borg. In this case, resistance is not futile – but it will definitely be challenging!
"a step too far in meddling with the building blocks of human life."
** title quote by Josephine Quintavalle of campaign group Comment on Reproductive Ethics
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