Junk DNA goodbye!: sex development control (Introduction)

by David Turell , Wednesday, June 20, 2018, 23:32 (2348 days ago) @ David Turell

In the non-coding region of DNA is an enhancer that controls sex organ development:

https://evolutionnews.org/2018/06/an-intimate-reminder-about-what-was-once-thought-to-b...

"Male mice grow ovaries instead of testes if they are missing a small region of DNA that doesn’t contain any genes, finds a new paper published in Science.

"The study, led by researchers at the Francis Crick Institute, could help explain disorders of sex development in humans, at least half of which have an unknown genetic cause.

"Mammals will develop ovaries and become females unless the early sex organs have enough of a protein called SOX9 at a key stage in their development. SOX9 causes these organs to become testes, which then direct the rest of the embryo to become male.

"The amount of SOX9 produced is controlled initially by the SRY protein encoded by the Sry gene, which is located on the Y chromosome. This is why males, who have an X chromosome and a Y chromosome, usually develop testes while females, who have two X chromosomes, do not.

"Only 2% of human DNA contains the ‘code’ to produce proteins, key building blocks of life. The remaining 98% is ‘non-coding’ and was once thought to be unnecessary ‘junk’ DNA, but there is increasing evidence that it can play important roles.

"The latest study adds to this evidence, showing that a small piece of DNA called enhancer 13 (Enh13), located over half a million bases away from the Sox9 gene, boosts SOX9 protein production at the right moment to trigger testes development. When the team genetically removed Enh13 from male (XY) mice, they developed ovaries and female genitalia.

"'Our study also highlights the important role of what some still refer to as ‘junk’ DNA, which makes up 98% of our genome. If a single enhancer can have this impact on sex determination, other non-coding regions might have similarly drastic effects.”

"The “junk” view, once a prized piece of evidence for neo-Darwinian theory, is thus reduced to the province of the benighted, the reactionaries who “still refer to [it] as ‘junk’ DNA,” after science has already passed them by. Having volumes of garbage lying around was a logical prediction of Darwinism that is in the process of being falsified. Now, it seems likely that non-coding regions have not trivial but “drastic effects.”

"This reversal helps explain why evolutionists like Richard Dawkins have radically revised a key claim. Dawkins himself, in the space of three years, went from assuring us that junk validates Darwinism to claiming that function is what it expects. What a theory! It can never, ever be wrong."

Comment: Junk DNA is disappearing, although there must be some that will exist after DNA is thoroughly studied. Dawkins was forced to change his view of the theory.