mutation
dr. dolittle | April 25, 2017
The August Krogh Distinguished lecture was awarded to Dr. Warren Burggren, who gave a fantastic lecture on epigenetics, or modifications to gene expression. He discussed how epigenetic changes to our genes are reversible. So when a stimulus like hypoxia changes our genes, these epigenetic changes to the genes go away rather quickly when the hypoxic insult is gone, which contrasts genetic mutations that arise from modifications to the genetic code leading to relatively permanent changes.
milhayser | January 26, 2015This new year, researchers concluded that 2/3 of the difference in cancer risk between different parts of the body can be attributed to the number of stem cell divisions those parts undergo. More cell divisions reflect a higher risk as errors that occur naturally during the DNA replication process can contribute to the development of cancer. In other words, the same genetic mutability that enables evolution also ensures that many people will be afflicted by a terrible disease. On Pharyngula, PZ Myers suggests this is one reason our cells naturally get old and stop dividing: because if they…
razib | December 31, 2009The Properties of Adaptive Walks in Evolving Populations of Fungus:
The rarity of beneficial mutations has frustrated efforts to develop a quantitative theory of adaptation. Recent models of adaptive walks, the sequential substitution of beneficial mutations by selection, make two compelling predictions: adaptive walks should be short, and fitness increases should become exponentially smaller as successive mutations fix. We estimated the number and fitness effects of beneficial mutations in each of 118 replicate lineages of Aspergillus nidulans evolving for approximately 800 generations at…
razib | March 9, 2009Advanced Paternal Age Is Associated with Impaired Neurocognitive Outcomes during Infancy and Childhood:
A sample of singleton children (n = 33,437) was drawn from the US Collaborative Perinatal Project. The outcome measures were assessed at 8 mo, 4 y, and 7 y (Bayley scales, Stanford Binet Intelligence Scale, Graham-Ernhart Block Sort Test, Wechsler Intelligence Scale for Children, Wide Range Achievement Test). The main analyses examined the relationship between neurocognitive measures and paternal or maternal age when adjusted for potential confounding factors. Advanced paternal age showed…
razib | March 8, 2009Evolution is a fact. Lineages change over time, and respond to selection pressures as well as being buffeted by stochastic processes. The arguments about the particular details of the process of evolution can be very vociferous. Scientists are human too, and great evolutionary biologists such as R. A. Fisher stooped to venomous insult when backed into a corner (see his disputes with Sewall Wright during the 1930s). But the superstructure of human foibles and follies rests upon a foundation of genuine scientific dispute, and attempts to refine models which map onto reality.
For example…
gregladen | February 19, 2009If Arnold was a bovine, he'd look like this.
Now, the lady cows say that they find this disgusting, but all the boy cows don't believe that and are intimidated nonetheless.
But seriously, this looks to me like a mutation that we've known about for some time, and published versions of mice that look like this cow (but with cute little ears and a different tail) are also out there somewhere. Imagine this mutation in a human. Would that be a Neanderthal? Sort of?
Story here.
zooillogix | December 28, 2008We (I) here at Zooillogix have a thing for lobsters. It involves Belgium, pasta tongs, and a Dutch boy named Lourens. I'll leave it at that.
Anyway, this mutant lobster was pulled out of the briny depths near Newport, RI earlier this month. Lobsterman Patrick Marks sometimes releases lobster "when they look at him funny" and so this almost-Pokemon-character was returned to the sea after a day-long publicity tour.
mikethemadbiologist | June 17, 2008I've noted before how stupid creationists are when they burble things like 'mutation is bad.' Well, a brief story in Nature once again shows just how stupid that whole idea is:
Publishing in Chemistry & Biology Truman et al. have identified a single amino acid substitution in the active site of the protein Cep15, which is part of the glycopeptide antibiotic chloroeremomycin biosynthetic machinery in Amycolatopsis orientalis, that abolishes its catalytic activity. Reversing a point mutation in the cep15 gene produced a functional enzyme. This finding represents the first time that the…
grrlscientist | June 13, 2008tags: researchblogging.org, evolution, experimental evolution, adaptation, mutation, natural selection, Richard E. Lenski
The common gut bacteria, Escherichia coli, typically known as E. coli.
Image: Dennis Kunkel.
Evolution is a random process -- or is it? I ask this because we all can name examples of convergent evolution where very different organisms arrived at similar solutions to the challenges they are faced with. One such example is the striking morphological similarities between sharks (marine fishes) and dolphins (marine mammals). Thus, based on observations of convergent…
zooillogix | June 11, 2008This Roe Deer was born in captivity at the research center of the Center of Natural Sciences just outside of Prato, Italy. With a single horn protruding from the center of its skull, Italian scientists believe that the animal either suffers from a unique genetic mutation or that it is a clear sign of the imminent second coming of Christ.
Special limited edition unicorn votives can be purchased at the Vatican this month only!
Single horned deer are rare, but not unheard of. However it is very unusual for the horn to be in the center of the head. Interestingly the unicorno's twin brother was…
zooillogix | June 5, 2007Two-tone lobsters are rare, only about 1 in 50 million share this mutation. They would be wise to increase the frequency of this variation however as it inevitably saves the little guy from the pot. Lobster shells have three primary pigment colors, red, yellow and blue. Occasionally lobsters lack one or more of these colors and because the two sides of a lobster shell develop independently, startling two-tone specimens are possible. Their less fortunate plain-Jane family members turn red in the pot because the heat frees the red pigment molecules, uncoiling them from the dark protein…
mikethemadbiologist | June 1, 2007And in other news, dog bites man. Would the NY Times have printed an op-ed allowing a flat-earther to explain why he believes the earth is flat? Because that's what they did when they ran Brownback's defense of intelligent design creationism. And there's nothing original in Brownback's op-ed either.
First, Brownback makes this declarative statement:
The heart of the issue is that we cannot drive a wedge between faith and reason. I believe wholeheartedly that there cannot be any contradiction between the two. The scientific method, based on reason, seeks to discover truths about the nature…
mikethemadbiologist | April 5, 2007From the archives comes this bit about the ludicrous (and willful) misunderstanding that creationists have regarding 'beneficial' mutations:
Whether they are young earthers or intelligent design advocates, one tactic creationists use is to claim evolutionary biologists-always described as "evolutionists"-think something which we do not. Over at Thoughts from Kansas, Josh had a very nice post describing the mechanisms by which mutations happen (among other things). Without fail, in charged a creationist:
The evolutionists make the claim that there are enough mutations that turn out to be…
mikethemadbiologist | March 15, 2007
To prevent brain damage, the Surgeon General recommends that statements by Michael Egnor be read using approved devices such as the StupidView9000
Orac bravely dives deeper into the Discovery Institute's creationist drivel, and reports on the continuing ignorant idiocy of Michael Egnor. I don't know what's worse: Egnor's willful ignorance, or his pseudo-victimization complex. Let's deal with the ignorance first.
In an interview with Casey Luskin, Egnor states (italics mine):
EGNOR: Well, it's a pretty funny claim on the part of Darwinists. It's sort of like Al Gore claiming that he…
mikethemadbiologist | February 24, 2007And it's free! Bob Altemeyer, whose work on the authoritarian mind significantly influenced John Dean'sConservatives Without Conscience, has released a free online book, The Authoritarians, which is about, well, authoritarians. Here's an interesting bit from the book about evolution from Ch. 4:
For the record, Darwin never said humans evolved from monkeys, even though many other people besides fundamentalists think he did. Even with the limited knowledge available to him 150 years ago, Darwin realized that humanity's ancestors had long separated from the evolutionary path that led to…
mikethemadbiologist | February 22, 2007Some of my fellow ScienceBloglings have written about Conservapedia's treatment of evolution. What has always puzzled me about creationists is the rather frequent denial of mutation. For example, in the section on macroevolution, titled "Is the theory of macroevolution true?"*--which should tell you what's to come right away, the entry reads:
2. Differences between organisms can be explained by known mechanisms of genetic mutation.
* Counter: There has not been enough time for mutation to generate existing biological diversity.
* Counter: There has been enough time enough…
mikethemadbiologist | January 18, 2007There's an article in the New Scientist about researchers who are using dichloroacetate ('DCA') to treat many different cancers. According to the article, here's what DCA does:
Evangelos Michelakis of the University of Alberta in Edmonton, Canada, and his colleagues tested DCA on human cells cultured outside the body and found that it killed lung, breast and brain cancer cells, but not healthy cells. Tumours in rats deliberately infected with human cancer also shrank drastically when they were fed DCA-laced water for several weeks.
DCA attacks a unique feature of cancer cells: the fact that…
mikethemadbiologist | July 10, 2006
Tara and Revere are both confronting the creationist anti-mutation 'argument.' I've faced this before regarding antibiotic resistance. I find it ironic that Mike Martin argues against evolution by mutation, when other creationists argue that small mutations happen, but 'kinds' are immutable. I wish these guys would figure out which idiocy they plan to adopt.