No expecting mother would ever wish harm to befall her children. Unfortunately, she may have no choice in the matter. Due to the rules of genetics, mums always run the risk of passing a “mother’s curse” onto their sons, but not their daughters.
The curse is an ancient one, the result of events that happened billions of years ago. At a time when all life consisted of single microscopic cells, one of these swallowed another. Normally, the engulfed cell would be digested, but not this time – this time, the two cells formed an alliance. The swallowed cell transferred many of its genes to its host, keeping only those involved in providing energy. It evolved into a mitochondrion – a tiny, efficient battery that would power its host, giving it the energy to become more complex. This alliance is the foundation of all complex life on the planet. All animals, plants, fungi and algae run on mitochondria power.
This means that all animals really have two genomes – their main nuclear one, and a far smaller secondary one in their mitochondria. The two sets of genes work together, each controlling the activity of the other. But they are inherited differently. The nuclear genome is a mash-up of genes from both parents, but the mitochondrial one only comes from mum. And this asymmetry is the reason for the mother’s curse.
In a lab in MIT, a flatworm is dying. It’s a planarian – a simple animal that is normally very difficult to kill. Planarians are masters of regeneration; whole animals can be reborn from small clumps of tissue. If you cut one in half, it will simply grow into two planarians. But this animal has been bombarded with high doses of radiation that have wiped out its ability to regenerate. Slowly, its cells are bursting apart. With no new ones to replace them, the planarian has a few weeks to live.
But Daniel Wagner and Irving Wang are about to save it, in a fashion. They transplant one special cell from a donor planarian into the terminal individual’s tail. The cell starts to divide. It produces skin, guts, nerves, muscle, eyes and a mouth.
As the planarian dies from the head backwards, the transplanted cells spread from the tail upwards. At its worst, the animal is a stunted mass with no discernible head. But two weeks after the transplant, it has completely regenerated. A new planarian has risen, phoenix-like, from the ashes. Its entire body is now genetically identical to the single transplanted cell. Read More
On May 7th, Robert Krulwich gave the commencement speech to Berkeley Journalism School’s Class of 2011. That’s Robert Krulwich, who hosts the singular radio show Radiolab, one of the most accomplished pieces of science broadcasting in any nation. Robert Krulwich, who won a Peabody Award for broadcast excellence a few months ago. Robert Krulwich, whose blog Krulwich Wonders should be on everyone’s reading list.
Robert emailed me a few days after the speech with the following:
“I wanted to let you know that after the meeting in North Carolina [Science Online 2011 – Ed], and after watching the little brigade of you and Carl and Brian and your sisteren and bretheren doing your up-from-the-streets form of journalism, I decided to turn you guys into a Important New Thing in The World. Over the weekend, I gave the commencement speech at Berkeley’s Journalism School and if you wade through the first two thirds, you become A Paradigm at the end. I don’t know if this is a gross over-Romanticization, but this is how it seems to me.”
I’ve always wanted to be a paradigm. I might get a T-shirt made.
Robert was kind enough to allow me to post the full text of his speech. It’s light, lyrical, full of stories – exactly what you’d expect. It’s long at 5,500 words but I really recommend reading it all. If you can’t, here’s a jump-link to the bit he mentions. But really, and especially if you have any aspirations to be a science writer or journalist, read it all.
This is Robert Krulwich speaking to our generation, telling us how things have changed, telling us to be hopeful, telling us how to win.