Talk:Direct DNA damage

notarobotyet
the DNA is wrong! the thymines shown are missing a methyl group — Preceding unsigned comment added by 141.14.245.147 (talk) 13:00, 16 April 2019 (UTC)

Someone
Someone who knows what they are doing here should add a link to Xeroderma Pigmentosum, as it provides an excellent example of what happens when the human body cannot appropriately handle direct DNA damage.

I also agree with the opinion form Philman132. I think this page and the page indirect DNA damage should be deleted. Their content can be integrated easily into the topics DNA repair and Ultraviolet. Moreover the information that 92 % of all melanoma cases is due to the effect of indirect DNA damage is wrong and should be corrected. I could myself make some fixes to the content, but someone with more Wikipedia experience should delete this pages. Rhahn (talk) 07:07, 28 May 2009 (UTC)

Indirect DNA damage citation
I think the statement "92% of all melanoma are caused by indirect DNA damage " needs proper citation because the Nature paper referenced by this article doesn't make this claim. Davies et al. writes:

"The highest frequency of BRAF mutations is in malignant melanoma (Table 1). This does not seem to be related to the effects of ultraviolet light, the only known environmental risk factor for this disease. The T -> A change at nucleotide 1796, which accounts for 35 of 38 (92%) of BRAF mutations in melanoma (Table 1), is distinct from the CC -> TT or C -> T changes associated with pyrimidine dimer formation following exposure to ultraviolet light—these changes are commonly found, for example, in the TP53 gene in non-melanoma skin cancers7."

The Nature paper only claims that 92% of BRAF mutations in melanoma are caused by a T -> A change at nucleotide 1796. While this BRAF mutation may be caused by indirect DNA damage, the authors make no claims that this particular mutation is resposible for 92% of melanomas.Biochemallurgist (talk) 21:39, 21 November 2010 (UTC)

Totally wrong title
Direct DNA damage is such as a huge subject that it is bizarre for this page to be only about UV radiation, which is just a small part in this field. Either change the title, delete it, or add other relevant mutagens that can cause direct DNA damage. UV-mediated direct DNA damage doesn't really warrant its own page, therefore it is better that direct DNA damage by other kinds of mutagens should be added. Hzh (talk) 10:57, 12 October 2011 (UTC)

ERROR IN IMAGE
The image of this article is incorrect. It portrays a dimer of two uracil molecules (which are only found in RNA) and does not show thymine as it presumes. The difference is small (thymine is methylated on the 5th carbon position) — Preceding unsigned comment added by Biopsinology (talk • contribs) 10:38, 23 June 2018 (UTC)

The subsections are fighting.
The subsections seem like they are arguing or trying to explain something to one another.

Also, referring to DNA as a nature-made molecule seems unnecessary and just sounds really weird. — Preceding unsigned comment added by 2601:241:8600:6A90:4954:852A:42F5:D764 (talk) 08:32, 7 September 2018 (UTC)

Missing a mechanistic explanation
Currently, the article reads as follows: "UVB light causes thymine base pairs next to each other in genetic sequences to bond together into pyrimidine dimers, a disruption in the strand, which reproductive enzymes cannot copy. It causes sunburn and it triggers the production of melanin.[1]"

First of all, it's replication enzymes - not reproductive enzymes. Took me some time to figure out why that didn't read right. That leads to the next question - how does the disruption of DNA replication lead to sunburn? This needs more of a mechanistic explanation in order to be informative.

That mechanism should have something to do with internal conversion to heat - as sunburn is a local heat dissipation event - that's why the burns are hot to the touch.. and get worse with time! The DNA is absorbing the vibrational energy of the sun and then directly transmitting those atomic vibrations to the surrounding medium in the form of heat - it's why DNA doesn't shake apart under UV radiation. That last part is only true in vivo, I think...

That would be a slight modification to the mechanism which is currently promoted for "sunburn", in that sunburn isn't caused by DNA damage - DNA damage is a marker of sunburn, sure. But that's only because the damage is a result of only 0.1% of the vibrational input the molecule is receiving - the rest goes straight as heat into the cell surroundings. This would result in an increase in molecular motion in the surrounding area, generating heat. So the sunburn is actually caused by the DNA saving itself from damage.. and the damage is what happens after it can't heat the surroundings any more. Shakes apart, maybe? — Preceding unsigned comment added by 2601:1C2:0:5B73:1DA7:16BA:D6B3:100B (talk) 19:30, 14 April 2019 (UTC)