July 4, 2008 | David F. Coppedge

How to Tell an Evolutionary Story

Thanks to Science Daily, we now know that “Evolutionary Origin Of Mammalian Gene Regulation Is Over 150 Million Years Old.”  The proof is easy.  It is so easy, in fact, that no proof is necessary.  One can merely assume it is true.  Trust them; they are scientists, after all.
Here is how the E word evolution was used in the article:

  • The findings, reported online in Nature Genetics, have provided new insights into the evolution of genomic or parental imprinting and epigenetic regulation in mammals.
  • Imprinting is thought to have evolved because of genetic conflict that influences the allocation of resources from parents to offspring.
  • The apparent absence of genomic imprinting in monotremes and presence in eutherians and marsupials suggests that imprinting has evolved at the boundary of monotremes and therians’ divergence.
  • Interestingly, imprinting evolution paralleled the apparition of the placenta and implantation.
  • Hence, it is possible that imprinting and placentation co-evolved in the therian ancestor.
  • The next stage is to look for the IGF2-H19 locus in another branch of mammals’ evolution
  • Recent evidence suggests that therians diverged from the egg-laying monotremes like the platypus approximately 180 million years ago, and then split into the eutherian and marsupials infra-classes around 150 million years ago.
  • Hence the … consortium will concentrate its efforts in obtaining the sequence of the monotreme IGF2 locus to provide further insights into the imprinting evolution and the mysteries of gene regulation in these curious creatures which carry mammalian, bird-like and reptilian characteristics.

Apparently the members of the consortium felt it superfluous to explain how the gene regulatory toolkit emerged through a random process of mutation and selection.  Science Daily was satisfied.  It summarized the paper by saying, “Scientists … have found that a complex, highly conserved and extremely important mechanism of controlling genes is over 150 million years old.”

Evolution is such a wonderful story.  It explains everything.  It conjures up such marvelous apparitions of mythical worlds in the far distant past.  Evolution is so versatile.  It mixes things up rapidly but then saves other things for 150 million years.  Who would have ever thought up such things.  Aren’t you glad we have the shamans to comfort us with their hidden wisdom?  Think how hard life would be if we actually had to think for ourselves.

Categories: Dumb Ideas, Genetics, Mammals

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