Slashdot Mirror
Evolution Can Occur Much Faster Than Previously Thought (ox.ac.uk)
An anonymous reader writes: An Oxford study on chickens discovered that evolution can make significant changes to a genome in as little as 15 years. "For a long time scientists have believed that the rate of change in the mitochondrial genome was never faster than about 2% per million years. The identification of these mutations shows that the rate of evolution in this pedigree is in fact 15 times faster." Professor Greger Larson, senior author on the study, said, "Our observations reveal that evolution is always moving quickly but we tend not to see it because we typically measure it over longer time periods."
Well considering that for the longest time, fossils were our main source of viewing evolution through time, of course it would seem to be slow. Who knows how many speciation events happen and die off before being able to leave a mark in the fossil record.
Those who do not learn from commit history are doomed to regress it.
Domesticated animals have changed significantly in the past few few decades let alone the past few thousand years. Modern broilers (meat chickens) can't even self procreate due to the changes but also grow from chicks to food in a couple months. Dairy cattle are another example, Today 9.3 Million dairy cattle produce 59% more milk than 25.6 Million cattle produced in the 40s. This isn't limited to animals, grain producing plants have significantly changed since the 30s, corn specifically has went from around 25 bushels per acre in the 30s to over 140 bushels per acre today. Anyone with even a passing knowledge of farming could have told you this. It should be noted though that while these plants/animals work well for modern farming, most would almost certainly go extinct after a few years without human care due to their extreme specialization (grain production, milk production, meat production, egg production etc).
There's a common misconception that fear can cause your hair to turn white. It's wrong, but true. What happens is that your hair us going white. It's 10% white, and nobody notices. 30% white and people can see it clearly, but don't point it out. But when you are at 30% white and have a strong fear event, you can have some hair fall out. The hair that falls out is disproportionately non-white. So it gives the appearance of a sudden whitening of your hair, caused by fear.
And my first thought on this was the same thing. Random mutation is long-term. But when a selection event happens, the "hidden" trait isn't created, but selected for. There is no "evolution", but a selection pressure that reveals the previous mutation as a preferential trait, making it appear to happen suddenly and revealed by the "cause" but not actually caused by the "cause".
Learn to love Alaska
Who is "we," kimosabe? Because the repeated emergence of antibiotic resistance, for example, is observed evolution. Then, if you're going to hang your hat on supposed horizontal gene transfer for antibiotic resistance, there's that niggling problem of emerging resistance to antimalarial drugs...
You-we may never have observed evolution, but medical-we certainly has.
Let me see if I understand. By measuring over a long period, we're measuring the long term rate of mutation survival after applying selection pressure, and that could be noticeably different than the raw rate of mutation. Is that a correct summary?
Please go slowly with me. I'm an engineer, not a biologist, and I admit biology is not my strongest subject. I am actually curious, though.
I remember hearing that there are large sections of DNA in many living things that are effectively "junk DNA," or at least we think are junk DNA. By junk DNA, I mean DNA that doesn't code for any useful proteins or other molecules, and generally seems to take up space. (I'm skeptical that there is much that is really "junk," but bear with me.) If there really are large stretches of non-useful baggage, it would stand to reason that these sections would not be subject to selection pressure, and so mutations to these sections aren't directly subject to selection pressure, because they don't affect the fitness of the organism.
Is there a way to measure the mutation rates for different sites in the overall genome of a given organism, so that: (a) we can determine if some regions are actually junk because mutations to them do not affect organism fitness, and (b) can distinguish between the rate of mutation and the rate of mutation survival? (This question more or less assumes my understanding in the first paragraph is accurate.)
Program Intellivision!