Joined: Nov. 2011
|Quote (qetzal @ Dec. 07 2011,21:03)|
|Quote (Southstar @ Dec. 07 2011,09:57)|
|The objection made to this article is that there is no proof of novel genetic material in the study. Actually in all fairness it does state "Tail clips taken for DNA analysis confirmed that the Pod Mrcaru lizards were genetically identical to the source population on Pod Kopiste."|
So one could assume that the mutations are only induced by the enviroment and are not genetic based?
Mutations are genetically based, by definition. And the DNA analysis did not confirm the the lizards were genetically identical. It only confirmed that the PM lizards were genetically indistinguishable from the PK lizards by the method employed. The test was only designed to show that the lizards collected on PM were, in fact, descendents of the original 5 pairs of PK lizards that were introduced to PM. That test was not designed to identify possible mutations in the PM lizards that might account for the observed physical differences.
|another thing I have replied to this saying that the development of the Cecal valve which is only been developed on the lizards of one island can only be produced with an increase of the amount of genetic material. Would this be correct? |
Or would it be possible that these genes were somehow latent and were only expressed when the animal turned to a heavier herbivourous diet?
No, I don't think you can't say the the development of cecal valves could only occur with an increase in the amount of genetic material. Remember that these lizards are descended from a total of 10 original lizards. So, any particular gene locus could have been present in multiple different versions (alleles) in the founding population. As the population expanded, those alleles would have reassorted into many combinations that weren't present in any single founding lizard. In addition, most traits are influenced by combinations of lots of genes and loci. So the appearance of cecal valves might not involve any new mutations. It might just involve new combinations of alleles that already existed individually in the founding population.
The fact that these traits appeared in only ~ 30 generations suggests to me that reassortment and selection of existing alleles is probably a significant factor here, though it's possible there were novel mutations as well.
Note that this is not really the same as saying that the genes were somehow latent, though your anti-evolutionist acquaintences may try to claim as much.
The problem here as I understand it:
There is a basic claim that the creationists make (well actually they are to scared to make a real claim) that evolution cannot "produce new information".
The example of the P.siculae lizard is brushed off as being a mix of adaptation And epigenetics:
According to the original paper, approximately 1 percent of reptiles include cecal valves meaning that there are around 80 species of reptile with cecal valves , including some Lacertid lizards besides Podarcis sicula. This suggests then that the genes that code for cecal valves may in fact be in all lacertid lizards, except the genes are not expressed, or turned "off". In the Pod Mr?aru population, adaptive pressures from the environment (i.e., lack of insects) triggered the expression of these genes.
No genetic testing hase been done on the lizards as far a sI can tell so we have no real way of saying that there has been a gain of function or a increase of genetic material in the new lizards.
Incidentely the claim of epigenetics is also called into question to explain what Lenski found in the CitT.
The argument is that it is impossible that millions of nucleotide sequences were generated in 30 years.
So the line is the following:
There are so very few examples of novel genetic material and most of them are deleterious to the organism anyway. (the examples so far are just twisted examples of very simple epigenetics). No new information is ever added. As Behe's study on "evolutionary law" showed most are loss of function or at best M.
The main tactic is as follows:
They do not argue that these mutations don't exist and they do not argue that microchanges are natural but just that 99% of these are loss of function and the 1% is mostly deleterious, the remaining slice is positive, but it's so little and so rare that it isn't enough to drive evolution. Therefore evolution is false. They do not (at this moment) indicate that there is a designer anywhere along the line but simply that the theory is a hoax.
Furthermore all examples of speciation are in line with their spiecies according to spiecies model, and none of them have any novel genetic material, or at least such a few have that it is neglegeble.
As further evidence of the impossibility of evolution there is the recent finding of ancient microbes that share 98% of the dna with modern versions. This is proof that the microbes are unable to evolve even in millions of years.
I wish I could find a knowlegble biologist willing to debate over there.
"Cows who know a moose when they see one will do infinitely better than a cow that pairs with a moose because they cannot see the difference either." Gary Gaulin