evolution
loom | March 13, 2006Natural selection can favor genes that allow children to grow up healthy. But in order to grow up healthy, they need nurturing from their mothers, both before and after birth. If a baby's development puts a strain on a mother, she may end up having fewer children. That means she may spread fewer copies of her genes to later generations . That creates conditions in which natural selection may also genes that allow mothers to restrain their children. Our particular way of having kids puts genes in conflict.
I have an article in tomorrow's New York Times on these conflicting genes, focusing on…
loom | March 13, 2006How do we know that we are kin to chimpanzees and howler monkeys and the other primates? For one thing, it's by far the best explanation for the fossil record. For another, our DNA shows signs of kinship to other primates, much like the genetic markers that are shared by people from a particular ethnic group. There's a third line of evidence that I find particularly fascinating: the viruses carried by humans and other apes.
Every day, viruses traffic in and out of human bodies. They invade people's cells, make new copies of themselves, and then, if they're lucky, infect a new host. Some…
razib | March 13, 2006The t-shirts which depict the "ascent of man" from hairy semi-ape to upright Homo sapiens might make you think that human evolution has been trivial since the emergence of our own species. Modern genomics suggests this isn't so, selection coefficients on the order of 1-10% are probably rather normal, and iterated over hundreds of generations that could result in a nontrivial amount of change on a quantitative trait.
I bring this up because a few days ago in The New York Times a piece was published titled The Twists and Turns of History, and of DNA. Greg Cochran (interest divulgence, a…
loom | March 11, 2006In trying to navigate the new ethical territory of blogging, I've decided to delete part of one of my posts. The full explanation is below.
Last week the story about the Turkish "quadruped" family was in circulation. I pointed to an article in which a Turkish scientist made an accusation of unethical payments against English scientists and a television company. When one of the English scientists, Nicholas Humphrey, complained in the comments that I was spreading "empty gossip," I updated the post with a partial retraction, apologizing for not following up on the accusation. However, I rebuted…
stcynic | March 11, 2006I picked up today's Grand Rapids Press and found an article on the front page of the religion section about Greg Forbes, one of my co-founders and fellow board members with Michigan Citizens for Science. Greg is a powerful speaker with an encyclopedic knowledge of evolution. He has trained thousands of teachers to teach evolution more effectively. He is also the founder of the Evolution Education Initiative and the evolution expert for the Michigan Science Teacher's Association. And next week, the ACLU is giving him an award as the Civil Libertarian of the Year for West Michigan. It has been…
evolgen | March 10, 2006I commented a couple of days ago on a news item about a journal article on the evolution of gene expression in primates that had yet to be published. Well, the article has been published, and I've read it (Nature has also published a news and views piece on the study by Rasmus Nielsen). I have a few comments on why this research is unique, what the researchers found, and the implications of this research below the fold.
WHY THIS STUDY IS UNIQUE: This is the first large scale study to examine gene expression in primates using species specific probes. Gene expression can be measured by…
razib | March 10, 2006Everyone and their mother has commented on the water found on Enceladus. There is speculation about life. If life doesn't exist on Enceladus, and to a good second approximation we should know in a few decades, I suggest seeding the moon with Terran organisms that might be able to survive and flourish. In a few decades genetic engineering might also progress to a point where exotic prokaryote metabolisms could be synthesized with the physiology of more complex aquatic organisms.
Nuts? Yeah, probably, but so what. I don't believe that God exists, but I suspect It might in the future.…
loom | March 9, 2006 Enceladus, a tiny moon of Saturn, suddenly gets interesting. It may be spewing liquid water. And since the only life we know of needs liquid water--and since Enceladus may now be the second place we know of in the solar system with liquid water--I want to buy a ticket there. Details and pictures here.
razib | March 9, 2006By now some of you have heard of the family that walks on all fours. I got a tip on this story weeks ago from World Science, which has been tracking this for a while and has a new update from a researcher that says this is a "credible" empirical finding. I didn't really intend to post about this for the following reasons:
1) A high probability that it is a hoax. The British media was the first mainstream organ to really take off with this, and they aren't known for their scientific credibility (Nature, The Daily Telegraph is not). Additionally, the findings are coming out of the heart of…
grrlscientist | March 9, 2006Salon has a fascinating article on their site about nanobiobots. Nanobiobots are the fusion of nanotechnology and biotechnology, which presumably will eliminate of the barrier between living and nonliving materials. As the result of this new technology, we will produce not mere cyborgs, but true hybrid artificial life forms, manifestations of synthetic biology. The potential biomedical benefits are astonishing, but the risks are at least as horrible to contemplate. Are we really ready for this? Is this the next step of evolution? What do you think? I linked to a long but very interesting…
evolgen | March 9, 2006Today marks the birthday of our venerable godfather (er, atheist-father?) here at ScienceBlogs, PZ Myers. I am honored and grateful that I have been invited to PZ Myers's . . . birthday . . . on the day of PZ Myers's birthday. And I hope that his first post be a cephalopod post. In appreciation of the blogfather, Grrlscientist is staging a surprise party -- a blogasm of posts -- for Doc Myers. My contribution can be found below the fold. I'm hoping that a list of all of the birthday posts will be compiled at Living the Scientific Life.
Shhh! Quick, hide behind that tree, the Lamarckian…
loom | March 9, 2006I've revisited the wrist walker story after a scientist involved accused me of spreading "empty gossip." I don't agree with that charge, but I do think I should retract some of what I wrote. But I've still got some nagging questions about the whole affair. Check it out.
jlynch | March 9, 2006This looks interesting. As I haven't seen the paper yet, I wont comment.
The vast differences between humans and chimpanzees are due more to changes in gene regulation than differences in individual genes themselves, according to a report in Nature. Using novel gene-array technology to measure the extent of gene expression in thousands of genes simultaneously, scientists provide powerful new evidence for a 30-year-old theory that might explain how only a few genetic changes could produce the wide anatomic and behavioral differences between the two.
Further details are below the fold.
Update:…
loom | March 8, 2006I've been in low-blogging mode for a few days as I try to fire off a few dead-tree articles. But I wanted to write up a quick post to draw your attention to threetwo very interesting pieces of human evolution in the news.
1. Modern evolution. A new paper presents the results of a systematic scan for human genes that have experienced natural selection in the past few thousand years. An impressive 700 regions turned up. The fact that humans have been evolving during recorded history is not new. The ability to digest lactose in milk as an adult, resistance to malaria, and other traits have long…
evolgen | March 8, 2006Kevin White (aka, Mr. Drosophila microarray data) has a paper coming out in tomorrow's issue of Nature. The paper (which is not available on the Nature website yet) compares the expression of over 1,000 genes from humans, chimpanzees, orangutans and rhesus monkeys. From a news write up of the findings:
When they also looked for human genes with significantly higher or lower expression levels, they found 14 genes with increased expression and five with decreased expression. While only ten percent of the genes in the total array were transcription factors, 42 percent of those with increased…
pharyngula | March 8, 2006
What do you think of when someone mentions the word "Kansas"? Maybe what leaps to your mind is that it is a farming state that is flat as a pancake, or if you've been following current events, the recent kangaroo court/monkey trial, or perhaps it is the drab counterpart to marvelous Oz. It isn't exactly first on the list of glamourous places. I admit that I tend to read different books than most people, so I have a somewhat skewed perspective on Kansas: the first thing I think of is a magic word.
Niobrara.
Late in the 19th century, there was a stampede to the American West to search for…
stcynic | March 7, 2006Reed Cartwright has the full text of a letter from Kentucky Governor Ernie Fletcher to the Kentucky Academy of Sciences. Fletcher is a creationist who has urged local school districts in that state to teach creationism. His argument is patently ridiculous. He actually argues that evolution conflicts with the Declaration of Independence. No, I'm not making that up:
Our nation, however, was founded on self-evident truths. Among these truths are inalienable rights "endowed by their Creator." From my perspective, it is not a matter of faith, or religion, or theory. It is similar to basic self-…
oracknows | March 7, 2006After all the violence and controversy over the Danish cartoons about the Prophet Mohammed, why is nobody protesting this real blasphemy?
evolgen | March 7, 2006This paper is rather timely considering I just finished reviewing methods for detecting natural selection. Jonathan Pritchard's group has scanned SNP data from three populations (Europeans, East Asians, and Nigerians) for signatures of positive natural selection. The authors used measures of polymorphism to detect natural selection. In their approach, they polarized polymorphic SNPs as ancestral and derived (kind of like a Fay and Wu test) using the other populations as outgroups. In this type of test, high frequency derived SNPs are a hallmark of recent positive selection; the authors…