There are many other molecules besides DNA that could be used to store genetic information. A recent study states that there are over one million man made or naturally occurring chemically identical molecules that have the ability to store biological DNA in a similar way that DNA does. This has the possibility to improve pharmaceutical drugs and explain the development of life on Earth and within the solar system. 

The authors of the paper used a computer program to generate chemical formulas that would have the nucleic acid like structure. They theorize that evolution may have tried a number of other molecules before nucleic acid was chosen to hold the genetic data. 

I find it interesting that so many other molecules with the ability to hold genetic data exist. This could be useful in medical fields as some drugs resembling nucleotides are already used in medicine. It is also interesting that this could give more information on the way that life developed on earth or if life could evolve on other planets. 

https://www.livescience.com/DNA-look-alikes-store-genetic-information.html

https://www.livescience.com/13363-7-theories-origin-life.html

Doubling Lifespan of Mice

In 2009, it was shown by the Spanish National Cancer Research Center under Óscar Fernández-Capetillo that mice age faster with low levels of ATR protein, an essential protein for the repair of damaged DNA, Stopping the premature ageing of these mice and doubling their life span has been achieved by introducing a mutation capable of increasing the body's capacity to produce nucleotides available in the cell.

This was originally tested in yeast, Saccharomyces cerevisiae, where it proved to be true and has since been tested on mice. The mice were given two genetic alterations with the first being the original ATR gene mutation that led to premature aging and the second which was the animals had multiple copies of Rrm2, the key gene for nucleotide synthesis. The results showed the aging process to be significantly slowed in these mice, taking their life span from 24 weeks to 50 weeks.

Every genome has weak or fragile sections which break spontaneously. These fragile sections have been shown to be involved in human diseases like cancer. The research paper showed that those mice with additional copies of Rrm2 suffered less DNA breaks in these fragile areas. "The question we are asking ourselves now is whether an increase in the capacity to produce nucleotides could also lengthen life expectancy in normal animals without premature ageing," says Fernández-Capetillo.

I found this article very interesting due to the research of prolonging and increasing the life span of animals. Although it is not said in the article I think it goes without saying that the obvious implications of a study like this is to eventually see if causing these same mutations in humans could lead to longer and healthier life spans.

Original Article: http://medicalxpress.com/news/2015-04-life-span-mice-premature-aging.html

Link Between DNA Transcription, Disease-Causing Expansions

     Scientists have known that long nucleotide base repeats in the human genome have led to heritable human diseases such as Huntington’s disease. Huntington’s disease is a neurodegenerative disease that affects muscle coordination and leads to a deterioration of cognitive thought. There are many nucleotide base repeats that are stable, but their lengthening over time leads to genome instability and changes in gene expression which can cause these diseases. Up until now, it was thought that the lengthening of these nucleotide base repeats was caused during DNA replication or when DNA repair machinery was active in the cell. However, it was found that the lengthening of these base pair repeats also occurs during transcription, which is the process of forming RNA from a DNA template within a cell.

                    

In a study performed by a research team led by Sergei Mirkin, the White Family Professor of Biology at Tufts' School of Arts and Sciences, the correlation between transcription and the expansion of base pair repeats was observed in yeast. The team used genetic systems to track the lengthening of nucleotide base pair repeats during DNA replication, DNA repair, and transcription. These genetic systems were also used to track the number of expansions in transcribed and non-transcribed parts of reporter genes. It was found that both transcribed and non-transcribed fragments of the reporter genes showed expansion, but the transcribed form of the reporter genes was ten times more likely to undergo the expansion process. This is because in a transcriptionally active state, the transcribed DNA segment has significantly less nucleosome density which leaves more room for repeat expansions of nucleotide base pairs.

                                      
     I find this article interesting because it relates the expansion of nucleotide base pairs to heritable diseases such as Huntington’s. By learning more about what causes these diseases, more efficient methods of treatment or cures can be discovered and implemented.

Source: Link Between DNA Transcription, Disease-Causing Expansions

The Half-Life of DNA

According to an article on Nature, paleontologists at the University of Copenhagen and Murdoch University have calculated that the half-life of DNA is 521 years. This was discovered in New Zealand, where the paleontologists examined 158 leg bones of three extinct giant bird species called moa. These leg bones contained DNA and were between 600 and 8000 years old. After a cell dies, enzymes break down the nucleotides that make up DNA. Much of the break down comes simply from reactions with water. However, groundwater is considered to be found everywhere and so DNA theoretically decays at a set rate. The half-life means that half of the bonds between the nucleotides in the DNA have been broken.



The paleontologists predict that at ideal preservation conditions, DNA would be fully broken down after a maximum of 6.8 million years. What this means is that the theories of dinosaur and insect DNA being trapped inside of amber are incorrect. Dinosaur bones are relatively 65 million years old, so the chances of being able to recover dinosaur DNA and possibly use that DNA to clone them (think Jurassic Park) are far out of the question.

While this find is unfortunate in an evolutionary perspective, it is still something that could be used to help date fossils and determine when extinct creatures existed, to an extent.