I’ve been meaning to get around to writing about female orgasms.
Category: Blog
It’s strange enough that beetles grow horns. But it’s especially strange that beetles grow so many kinds of horns. This picture, which was published in the latest issue of the journal Evolution, shows a tiny sampling of this diversity. The species shown here all belong to the genus Onthophagus, a group of dung beetles. The colors in this picture, which are false, show which parts of the beetle body the horns grow from. Blue horns grow from the back of the head, red from the middle of the head, and purple from the front of the head. Green horns grow from the center of the body plate directly behind the head (the pronotum), and orange horns grow from the side of the pronotum. These beetles can grow horns big and small, single or multiple, shaped like stags or like rhinos. And, as these colors show, the beetles can take very different developmental paths to get to their finished product. The biologist JBS Haldane was supposedly asked once if he could say anything about God from his study of nature. Haldane replied He must have an inordinate fondness for beetles. Add to that a fondness for putting horns on those beetles.
Today in Science scientists reported a potentially big advance in creating embryos that can be used for stem cell transplants. Briefly put, they figured out how to take skin cells from patients, inject them into donated eggs emptied of their own DNA, and nurture them along until they had divided into a few cells. The cells were able to develop into a wide range of cell types, their chromosomes were normal, and they were so similar to the cells of the individual patients that they would not be rejected as foreign tissue. The research stopped there, but the dream behind this work is to heal your failing liver or heart or dopamine-producing neurons by clipping off a little skin and farm new cells that could regenerate those organs.
Continue reading “Of Stem Cells and Neanderthals: Closing the Circle”
Blogging will be light for a few days because my hard drive devoured itself last night. I just wanted to mention a couple brain-related items. First off, I’ve got a profile in today’s New York Times of Michael Gazzaniga, one of the most fascinating people involved in science today. His research on the split minds of people with split brains would be fascinating enough, but now he’s trying to use these insights to make sense of the confusing choices that bioethics now forces us to make. (Gazzaniga’s a feisty member of the President’s Council on Bioethics.)
Judging from fossils and studies on DNA, the common ancestor of humans, chimpanzees, and bonobos lived roughly six million years ago. Hominids inherited the genome of that ancestor, and over time it evolved into the human genome. A major force driving that change was natural selection: a mutant gene that allowed hominids to produce more descendants than other versions of the gene became more common over time. Now that scientists can compare the genomes of humans, chimpanzees, mice, and other animals, they can pinpoint some of the genes that underwent particularly strong natural selection since the dawn of hominids. You might think that at the top of the list the scientists would put genes involved in the things that set us apart most obviously from other animals, such as our oversized brains or our upright posture. But according to the latest scan of some 13,000 human genes, that’s not the case. Natural selection has been focused on other things–less obvious ones, but no less important. While the results of this scan are all fascinating, one stands out in particular. The authors of the study argue that much of our evolution is the result of a war we are waging against our own cells.