Sunday, April 5, 2015

Top Geneticist Rejects the "Junk DNA" viewpoint

Oh look! I have in my hand the most up-to-date book available,
on Mobile DNA. Its by the world's leading expert on that topic.

Oh oh, he's not an ID guy. He's not a creationist.
OMG he's not even a Christian or Jew, or muslim.

The title is hilariously "Mobile DNA", by H.H. Kazazian, (2012, FT Press).

We'd better check his credentials:
We wouldn't want any 'unscientific' amateurs sneaking in,
misrepresenting themselves and taking credit for BAs in philosophy,
or PhDs in religion here:

Hmmm. lets see:

finished his M.D. degree at Johns Hopkins University School of Medicine.

Interned in Pediatrics at University of Minnesota Hospital.

Returned to Johns Hopkins for a Fellowship in Genetics,

Then Trained in molecular biology at the NIH.

Rejoined the Faculty at Johns Hopkins.

Rose to full professorship there in 1977.

Became Director of the Center for Medical Genetics (Johns Hopkins) 1988.

Spent 25 years on the John Hopkins Faculty.

Recruited to University of Pennsylvania School of Medicine, as
Chair of the Dept. of Genetics in 1994.

Remained as Seymour Grey Professor of Molecular Medicine in Genetics till 2010.

Returned to Johns Hopkins in July 2010.

Heavily involved in molecular genetic research for the past 20 years
specializing in mammalian and human transposable elements, "jumping genes".

Personally characterized much of the variation in the cluster of genes
involved in production of the beta chain of human hemoglobin.

His work led to the nearly complete characterization of the mutations
causing the Beta-thalassemias, common anemias in malaria regions.

Received many honours for his research, most notably the
2008 William Allan Award, the top honour of the
American Society of Human Genetics.

Well, what does he say about Junk DNA?

"...most genes are broken up by sections of DNA called introns
that need to be removed at the RNA stage in order for the genes
to function. ...the protein-coding regions of the genes make up
a very small fraction of mammalian genomes.
...In the late 1970s, introns were found...
Soon we knew that introns were much larger than protein-coding regions,
then called exons.
The DNA between the genes was thought to be functionless,
and was called "junk DNA" (Orgel and Crick, 1980).
However, now we know that introns make up about 30% of human
and mammalian genomes, and exons only encode between 1 and 2%
of the human genome (Lander et al., 2001).
What a comedown for the protein-encoding regions!
Thus over 98% of human DNA had been dismissed as "junk".

Transposable elements were then found, and this active mobile DNA
along with the remnants is now known to account for at least 50%
of human genomic DNA. Both the relatively few presently mobile
sequences, and the many remnants of old events are now
demonstrating function.

...evident in the many ways mobile DNA can modify the genome over evolutionary time.
It can also be co-opted for useful purposes...
Moreover, DNA encoding small RNAs of different types and functions
has been discovered amidst the "junk". Enhancer sequences at great
distances from the genes upon which they act are being found continually.
The bottom line is that "junk" DNA is gradually being eroded away as
function is found for a greater and greater fraction of the genomic DNA

- Mobile DNA, pp. 1-3

His comfortable use of "evolutionary" makes clear he is an evolutionist,
as well as one of the top experts in human DNA.

No comments: