Looking for evolutionary info on how smells can be carried on DNA
As I said last night the smell of pus from an infection is recognized by all puppies without their being exposed to the smell previously, this is shown because all puppies react the same way to this smell, which is to lick the infected pus laden wound.
This demonstrates that smells are carried on DNA in some way. Any thoughts on how?
The rule in gene survival is "use it or lose it".
When a gene ceases to be useful, mutations are likely to accumulate as they are passed on down the generations. These broken genes are called pseudogenes and they provide powerful clues to our evolutionary past.
Compared with other animals our ability to detect odours is poor, but if evolution is correct there was a time in our distant past when we relied on our sense of smell much more than we do today.
Our olfactory receptors are coded for by OR genes. Geneticists Linda Black and Richard Axel won the Nobel Prize in 2004 for their work in this field. They discovered that humans have 800 such genes but fully half of these are inactive relics of our past. As our brain combines signals from a number of receptors simultaneously that means our sense of smell is only a fraction of what it once was.
What though of our closest relatives? Well not surprisingly there was found to be a direct correlation between the closeness of our evolutionary cousins and the number of active and inactive OR genes. We carry this genetic baggage because it was needed in our distant ancestors who relied on a keen sense of smell for survival.
Clearly a mechanism that enables us to detect airborne odours is not going to work the same under water. In fish we find one kind of OR genes and in amphibians and mammals there is another. So what about aquatic mammals like dolphins? If they really were once land animals as evolution claims, there should still be evidence in their genome that they once had an acute sense of smell.
Not surprisingly the evidence is irrefutable. 80% of the OR genes in a dolphin are inactivated; hundreds of them remain in their genome as silent testimony to their evolutionary past. Dolphins have the instructions in their genes to construct the tools for detecting thousands of airborne smells. This makes no sense if dolphins were specially created.
The most primitive fish still alive today is a jawless fish called Lamprey. Fossils of these creatures 320 million years old bear a very close resemblance to it’s modern cousin. When the DNA of the lamprey is studied it turns out their OR genes are neither air nor water specific; they combine features of both. These creatures arose before smelling genes split into two types.
Like all our other genes our OR genes tell a story of our species’ past. They are very similar to primates, less similar to other mammals, less similar still to reptiles, amphibians and fish in that order..
Perhaps Dolphins used to smell above the surface of the waters, before the great flood of Noah's day? A more humid enviroment, owing to the water canopy, would trap more smells near the surface of the waters.
Once the water canopy was removed, ultra-violet radiation increased, causing Dolphins to spend more time beneath the water? Over the last few thousand years, they lost their ability to smell?
But cofty you have missed the point, smells are not genes. There is clear evidence that the smell of pus and flowers can be passed down as a memory to the offspring.
Data Dog this has nothing to do with either Dolphins or Noahs imaginary flood, or the imaginary apocolypses in 1914 and 1975
Our brains are built by genes. Our instincts are hard wired by genetic switches. We avoid dangerous heights, snakes, things that roar, shagging our relatives, eating shit and things that smell of puss because genes wired our brains that way.
Would you like some book suggestions?
cofty all of that is true, what I am asking is how does the DNA carry a smell which is not part of the body from one generation to the next. You are in agreement with me that it happens so far as I can tell, however you like 99.9 percent of others just accept this without asking why. Trust me, there is no book that you can read that answers this question, the books just verify that it happens.
Viv will claim to know...................
There is clear evidence that the smell of pus and flowers can be passed down as a memory to the offspring.
It's clear that you don't know what "evidence" and "memories" are.
Wrong Viv.................you are an ignorant fish on the hook. You will learn that I am never wrong.