Bird study reveals a key assumption in evolution theory is false
Bird study reveals a key assumption in evolution theory is false
http://sciencenordic.com/bird-study-reveals-key-assumption-evolution-theory-falseExcerpt: "A new study of fifty bird species from the Andes now rules out any possibility of predicting evolution on a single genetic mutation.
The scientists wanted to study oxygen uptake in the blood at various altitudes, so these birds were the ideal test subjects.
“These birds live both at high altitudes and at sea level, so they’re a good case study. Our data show that haemoglobin in birds living at higher altitude can take up oxygen more effectively. And we wanted to study this difference at the genetic level,” says Fago.
The scientists took samples from 50 different species of birds that live at various altitudes in the Andes. They compared the blood analysis with the genes that are responsible for producing haemoglobin.
But what they discovered, was unexpected.
Birds living at high altitude, need to be specially adapted to cope with low levels of oxygen.
The scientists’ hypothesis was therefore that these birds would have a definite pattern of mutations that enabled them to do this.
“But we didn’t see any patterns in the birds’ genes. We thought there would be clear similarities among the high-altitude birds, but there’s clearly more than one recipe for this special haemoglobin [mutation],” says Fago.
Even though two individuals have the same mutation on one gene, it does not necessarily mean that they both have the same effect, says Zhang. So scientists will need to test the manifestation of these mutations in practice and not just rely on computer models.
This study warns us that we can’t draw direct links between genes and their function in individuals,” he says."
This study warns us that we can’t draw direct links between genes and their function in individuals,” he says."
My comment: Hemoglobin production is based on several factors and it is regulated by epigenetic control of gene expression. The most significant factors in regulation of hemoglobin variants and their subunits are DNA methylation, histone methylation/acetylation and microRNA downregulation.
Keywords: hemoglobin gene expression splice variant
http://www.sciencedirect.com/science/article/pii/S1931524414001650
The most important observation was that genetic mutations didn't correlate with assumed hemoglobin variants. Random mutations didn't affect the phenotype as researchers had assumed. Then how those genetic mutations are explained?
Intensive adaptation changes epigenetic patterns and this leads to mechanism based sequence alterations. Methylated cytosines turn easily into thymine, guanines to adenine and hydroxymethylated cytosines into guanine. This kind of point mutations have no role for ecological adaptation except that they only burden the gene regulatory networks because faulty genes consume energy. RNA mediated cellular mechanisms try to hide and pack this kind of faulty genes from getting to transcription. This can be observed as chromatin remodeling and even chromosome loss.
This same phenomenon can be observed in the human DNA: There are about one million SNPs, 200 000 disease-causing genetic mutations in the human genome. 10 000 new genetic errors are discovered every year. Genetic entropy, rapid degradation of genomes within all organisms is an observable fact.
Again, we have a clear example of how the gene centric evolutionary theory includes serious fallacies. Gene sequences alone don't determine traits. Genes are not drivers. There is no such a thing as a mutation driven evolution. Don't get lost.
Comments
Post a Comment