Map of life expectancy at birth from Global Education Project.

Tuesday, March 18, 2014

Science Journamalism

Wow. Just wow.  One Marcy Darnovsky, executive director of an institution called the Center for Genetics and Society, doesn't know anything at all about genetics.

Here's the story. Shoukhrat Mitalipov, a Soviet emigré scientist, has figured out how to insert the nucleus of a human zygote (a fertilized ovum) into the cytoplasm of a donor ovum. The reason for doing this is to make it possible for women who have genetic mitochondrial disorders to have healthy biological offspring.

For those of you who need the background science, it's actually a very interesting fact about our deep evolutionary history. The eukaryotic cell, which is what we are built out of along with all the plants and animals, is the product of a very ancient event in which primitive bacteria became endosymbionts within larger cells, probably archaea.* It may be that the archaeal cell ingested a bacterium, but failed to digest it. The DNA of the archaeal cell is now (apparently) essentially the DNA in our cell nuclei, what we call our genome. (It's possible that some of it derives from the endosymbiont. Some of it also derives from retroviruses. It's a long story. But anyway . . .

Those symbiotic bacteria are now what we call mitochondria, organelles within our cells that generate the energy the cell needs to fuel its chemical machinery. They have a very small genome of their own, just enough to keep them alive and functioning within the highly specific environment of the cytoplasm. And their genes do not determine anything about us, whatsoever, other than how well our mitochondria function. We get 100% of our mitochondrial genes from our mothers, the father's genome has nothing to do with it, because the mitochondria in all of our cells are descendants of the mitochondria in the ovum from which all of our cells descend. In other words, the mitochondria do not reproduce sexually and they have their own, independent line of descent which is exclusively maternal.

So here's what Marcy Darnovsky says:

His research has brought persistent criticism. “If these procedures are carried out, it crosses a very bright line,” said Ms. Darnovsky of the genetics center. She said that the current goal, mitochondrial replacement, may be narrow, but that Dr. Mitalipov’s genetic techniques could lead to broader applications and eventually to a situation in which scientists or governments “compete to enhance future generations,” such as producing soldiers who never need sleep.

No. Completely wrong and astonishingly ignorant. Dr. Mitalipov isn't even using genetic techniques at all. He isn't going near the human genome and what he is doing cannot create enhanced future generations or affect people's sleep or anything else about them. The only thing it can do is create a baby with healthy mitochondria. Period. End of story. One would think that the executive director of the Center for Genetics and Society would know the first thing about genetics. Sadly, no.

The additional problem is that the New York Times science journalist who wrote this story doesn't understand this either, and didn't bother to ask anybody who could explain it to her.

* Archaea and Bacteria are two different kinds of single-celled organisms, which are considered separate "kingdoms," which diverged very early in the history of life on earth. They appear superficially very similar but have large differences in their cellular machinery.

1 comment:

mojrim said...

Damn, that's pathetic. I learned that much in a community college biology class...