Video Of The Week: What is DNA and How Does it Work?

One of our colleagues at USV pointed us at a series of web videos called Stated Clearly.

I really like this one that explains DNA and how it works in a very simple and easy to understand way.


Comments (Archived):

  1. William Mougayar

    Good intro, but they don’t mention telomeres, an important aspect of DNA understanding we can do something about. Telomeres are the protective caps at the ends of the DNA, and they are markers of biological aging, because they shorten with each cell division. You can preserve your telomeres by matching proper nutrition & exercise based on your detailed findings.I recently did 2 DNA tests to check my DNA out. One of them, specializes in telomeres analysis, and it provided me with valuable information which made a lot of sense.

    1. Greg Kieser

      Concur. And to a lesser degree is the role of sirtuins on transcription – also with longevity implications.

      1. Vendita Auto

        Reading “The China Study” was a game changer for me even at a later timeline. only the statistical percentages were of interest in offering longer term health options I can mix or match.

    2. Vendita Auto

      Not sure I would allow ones family DNA without knowing the security implications ? I know Craig Venter would not: https://www.washingtonpost….

      1. William Mougayar

        I don’t understand “security implications”?

        1. Vendita Auto

          It is your “personal” DNA when/if using the DNA collection kit what is the security status of FindRthm ? inherited diseases, forensic tests, insurance ………… cross selling they are the questions I would want to know.

          1. William Mougayar

            Got it. Thanks

          2. ShanaC

            In the US, you can’t discriminate for health insurance based on genes

          3. Vendita Auto

            Thanks ShanaC, That along with the other reasons is not a risk I would take for myself or ones family, hope you get time to watch the Craig Venter vid it is worthy

    3. Girish Mehta

      Small but relevant edit – they are present at the ends of chromosomes.

    4. CorkageVIP

      William, thanks for the tip! I just downloaded the app and measured my heart rate for starters by holding the phone against my chest. The app also claims partial comparability with other genetic providers such as 23andMe if one already has genetic testing results.

      1. William Mougayar

        Right. The heartbeat measurement is a neat trick. It gets people excited.Yes, you can import other DNA data into their app, but I believe they are the only ones that provide the in-depth on the telomeres.

    5. Richard

      Yep. But it’s a little early in the game to think ones absolute telemere Length in the lukocyte cells that most tests look at will be a good predictor of other cells throughout the body.AbstractPurpose of reviewThere has been growing evidence that lifestyle factors may affect the health and lifespan of an individual by affecting telomere length. The purpose of this review was to highlight the importance of telomeres in human health and aging and to summarize possible lifestyle factors that may affect health and longevity by altering the rate of telomere shortening.Recent findingsRecent studies indicate that telomere length, which can be affected by various lifestyle factors, can affect the pace of aging and onset of age-associated diseases.SummaryTelomere length shortens with age. Progressive shortening of telomeres leads to senescence, apoptosis, or oncogenic transformation of somatic cells, affecting the health and lifespan of an individual. Shorter telomeres have been associated with increased incidence of diseases and poor survival. The rate of telomere shortening can be either increased or decreased by specific lifestyle factors. Better choice of diet and activities has great potential to reduce the rate of telomere shortening or at least prevent excessive telomere attrition, leading to delayed onset of age-associated diseases and increased lifespan. This review highlights the role of telomeres in aging and describes the lifestyle factors which may affect telomeres, human health, and aging.Keywords: aging, cancer, lifestyle, oxidative stress, telomereIntroductionTelomeres, the specific DNA–protein structures found at both ends of each chromosome, protect genome from nucleolytic degradation, unnecessary recombination, repair, and interchromosomal fusion. Telomeres therefore play a vital role in preserving the information in our genome. As a normal cellular process, a small portion of telomeric DNA is lost with each cell division. When telomere length reaches a critical limit, the cell undergoes senescence and/or apoptosis. Telomere length may therefore serve as a biological clock to determine the lifespan of a cell and an organism. Certain agents associated with specific lifestyles may expedite telomere shortening by inducing damage to DNA in general or more specifically at telomeres and may therefore affect health and lifespan of an individual. In this review we highlight the lifestyle factors that may adversely affect health and lifespan of an individual by accelerating telomere shortening and also those that can potentially protect telomeres and health of an individual.Structure and function of telomeresTelomeres, the DNA–protein complexes at chromosome ends (Fig. 1), protect genome from degradation and interchromosomal fusion. Telomeric DNA is associated with telomere-binding proteins and a loop structure mediated by TRF2 protects the ends of human chromosomes against exonucleolytic degradation [1], and may also prime telomeric DNA synthesis by a mechanism similar to ‘gap filling’ in homologous recombination [2]. As shown in Fig. 2, telomere shortening occurs at each DNA replication, and if continued leads to chromosomal degradation and cell death [3]. Telomerase activity, the ability to extend telomeres, is present in germline and certain hematopoietic cells, whereas somatic cells have low or undetectable levels of this activity and their telomeres undergo a progressive shortening with replication (Fig. 2). Telomerases are reactivated in most cancers and immortalized cells. However, a subset of cancer/immortalized cells lack telomerase activity and maintain telomere length by alternative mechanisms, probably involving genetic (homologous) recombination [4], which is elevated in most immortal/cancer cell lines [5]. We have found that telomerase physically interacts with recombinase family of proteins and inhibitors of homologous recombination reducing telomere length in telomerase positive Barrett’s adenocarcinoma cells (unpublished data from our laboratory). This suggests that recombinational repair is closely connected to telomere maintenance.Figure 1Figure 1Telomeres, the DNA–protein structures which protect chromosomesFigure 2Figure 2Length of telomeric DNA is important for lifespan of a cellTelomere shortening, cancer, and agingTelomeres shorten with age and rate of telomere shortening may indicate the pace of aging.Telomere length decreases with age and may predict lifespanNormal diploid cells lose telomeres with each cell division and therefore have a limited lifespan in culture. Human liver tissues have been reported to lose 55 base pairs of telomeric DNA per year [6]. Rate of telomere shortening in rapidly renewing gastric mucosal cells is also similar to that observed for liver tissue. The expression of stathmin and EF-1a, the biomarkers for telomeric dysfunction and DNA damage in a cell, increases with age and age-related diseases in humans [7,8]. Telomere length negatively correlates with age whereas the expression of p16, which increases in aging cells, positively correlates with age [7,8].Accelerated telomere shortening in genetic disorder dyskeratosis congenital is associated with an early onset of several age-associated disorders and reduced lifespan. Telomerase activity, the ability to add telomeric repeats to the chromosome ends, is present in germline, hematopoietic, stem, and certain other rapidly renewing cells but extremely low or absent in most normal somatic cells. Transgenic induction of a telomerase gene in normal human cells extends their lifespan [9]. Cawthon et al. [10] showed that individuals with shorter telomeres had significantly poor survival due to higher mortality rate caused by heart and infectious diseases. Progressive shortening of telomeres leads to senescence, apoptotic cell death, or oncogenic transformation of somatic cells in various tissues. Telomere length, which can be affected by various lifestyle factors, may determine overall health, lifespan, and the rate at which an individual is aging [11•].Accelerated telomere shortening may increase the pace of agingAs a normal cellular process, telomere length decreases with age [12,13]. Telomere length in humans seems to decrease at a rate of 24.8–27.7 base pairs per year [12,13]. Telomere length, shorter than the average telomere length for a specific age group, has been associated with increased incidence of age-related diseases and/or decreased lifespan in humans [10,14,15]. Telomere length is affected by a combination of factors including donor age [16], genetic, epigenetic make-up and environment [17–20], social and economic status [21,22], exercise [21], body weight [12,23], and smoking [12,24]. Gender does not seem to have any significant effect on the rate of telomere loss [13]. When telomere length reaches below a critical limit, the cells undergo senescence and/or apoptosis [25,26].Certain lifestyle factors such as smoking, obesity, lack of exercise, and consumption of unhealthy diet can increase the pace of telomere shortening, leading to illness and/or premature death.

      1. William Mougayar

        Exactly. I’m learning more about it too. Rhtm gets into specific recommendations based my own DNA findings, but to sum it up, it’s a combination of nutrition, exercise and sleep. It re-enforces what you have been doing right and reminds you of what you have not been doing right.

    6. Lawrence Brass

      Telomeres are like the protective end caps found in shoe laces [1].I wonder if, as genetic technology advances and genetic awareness sets in society, that could produce a form of gene-ism similar to racism, ageism or gender discrimination.There goes William, the guy with the long telomeres. :)[1] These actually have a name, they are called aglets. Thanks Google and Wikipedia.

  2. Eric Friedman

    I always think about Dino DNA

    1. fredwilson


  3. Pointsandfigures

    If we let it happen, in the next 10 years we will have customized drugs made just for you.

    1. LE

      Unintended consequences of medical advances is that people will follow more risky behaviors because they know there is a treatment that can dig them out of the mess they have made for themselves. This has been already happening but it will get worse. One of the reasons that our healthcare costs have risen for sure.

      1. jason wright

        “Mess they have made for themselves”.Advertising is designed to tap the mind. It’s psychological warfare by corporates on consumers. It’s tough for the average individual to win. They need assistance in the battle.

  4. WA

    Awesome trip back to 10th grade biology! What a great set of clearly stated lessons all around. Should be a must watch for every kid in every higjschool science and other classes. . Nothing like good coding lessons…especially biological!

  5. jason wright

    Stated clearly, but still complicated. That ladies and gentlemen is the form of modern life, complicated.

  6. John Rhoads

    Super rad

  7. Richard

    Knowing about DNA is cool and captures a lot of headlines, but knowing about pathways and the immune system is where the action is.The pathway below is how we produce the magical heme molocule.https://uploads.disquscdn.chttps://uploads.disquscdn.c

  8. JAJones

    I like it…kind of a short video form of . If you’re interested in this topic I recommend checking out the book The Immortal Life of Henrietta Lacks which is also slated to debut on HBO in 2017 starring Orpah… . Currently reading The Gene by Siddhartha Mukherjee – fascinating book about the discovery of genes and the future of genetics.

  9. Pete Griffiths

    good general educationbutthe state of the art is so technicallet’s not pretend to have any idea what they are up do

  10. Jan Schultink

    The real overwhelming realization about the complexity of this comes when you see protein construction in 3D. Forget all about the difficult terms and letter codes, but just see how the 3 dimensional shapes and angles determines whether something binds or not.Some of my clients are working on genetic diseases and use computer models to zoom in on a tiny, tiny fraction of these genetic strands and you can sort of stand in the middle of them and see what happens and does not happen. (VR will be interesting here 🙂 )

  11. ShanaC

    You might like the book, “The Gene.” It’s by the same guy who wrote “The Emperor of All Maladies”

  12. mikenolan99

    I miss @FakeGrimlock…

  13. Salt Shaker

    Wow, that’s some story. Sounds like grandpa was a stud 🙂