Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Scientists Examining DNA of Centenarians

Tags:
  1. Oct 27, 2011 #1
    http://news.yahoo.com/longevitys-secrets-sought-dna-100-olds-203909753.html

    Apparently, there's something good in their genes! "By the time you reach, say, 105, "it's very hard to get there without some genetic advantages," says Dr. Thomas Perls, a geriatrics expert at Boston University."

    We've been hearing about gene therapy for years, but what's the likelihood of devising a therapy to correct our deficient DNA, repairing it with theirs, so that we can live longer lives?
     
  2. jcsd
  3. Oct 27, 2011 #2

    Ryan_m_b

    User Avatar

    Staff: Mentor

    To be honest this is mainly for show in my opinion. We finished the human genome project a decade ago and in decades hence we will still be deciphering the data. And that's before we start talking about transcriptomics, proteomics, metabolics and the myriad of environmental factors that lead to the phenome. Out of those hundred hundred year olds it's going to be impossible to tease out any genetic vs environmental link.

    Another problem is that there is not going to be some magic longevity gene. Their phenotype is not only complex interplay between their genes and environment but also between their all of their genes. How would you know which complement of genes was responsible? Without creating thousands of knock-out variants and watching them grow for a century.
     
  4. Oct 27, 2011 #3

    Ygggdrasil

    User Avatar
    Science Advisor

    The scientists about whom the Yahoo article reports previously published a paper in Science detailing some of the findings of their sequencing project. They claimed to find certain gene variants that seemed to appear more frequently in the centenarians than in the control population. However, other genetics researchers quickly noted some flaws in the study's design and further experiments showed that the paper's findings were just an artifact: the gene chips used to study the control population have slightly different biases and sensitivities than the gene chips used to study the centenarian population. Thus, the paper was subsequently retracted in July of this year.

    This case is a cautionary tale of just how difficult it is to tease out very weak correlations from a very messy data set. Given the complex interactions between genes and environment, designing a study with the statistical power to find such correlations is extremely difficult.
     
  5. Oct 27, 2011 #4
    Just started reading the book https://www.amazon.com/Outliers-Story-Success-Malcolm-Gladwell/dp/0316017922" in Pennsylvania. Apparently the community was studied by scientists because the residents were living very long and healthy lives. The scientists studied all aspect including genetic advantages. They couldn't find anything different. They concluded it was the communities close Italian culture which led to long life.
     
    Last edited: May 5, 2017
  6. Oct 28, 2011 #5
    Thanks for the responses!

    Alternatively, starting with two large groups, those who are otherwise healthy yet die of old age less than 70 yrs old, and every centenarian one can get to donate some DNA. No need to track everyone and determine the differences over 100 years.

    However, as you said, the complexity of interactions between myriads of genes would probably require very large sample populations to resolve any clear results.
     
  7. Oct 28, 2011 #6

    Ryan_m_b

    User Avatar

    Staff: Mentor

    Interesting, I wonder why they came to that conclusion. It's a fantastically hard thing to do, it makes me laugh to read old science fiction from the 80s and 90s where they made the mistake of assuming that once we've cracked the genome we've cracked the phenome. The reality is we're barely any closer to the latter!
    It would still be extremely hard. The problem is ironically a lack of data combined with too much data. In other words even if even with thousands of people with detailed medical and personal histories as well as full genome data for all we are still missing huge swathes of their life that may be important (that's not to suggest that there's some fountain of youth that half of them live next to, just that the variables and combinations are gargantuan). On the other hand all the data we do have is a mountain to get through; I can't remember who said it but there's a quote about the results of the human genome project that goes something like "After ten years we have an ocean of data and a puddle of knowledge".

    That's not to say there isn't hope. We are getting closer to understanding how phenotypes are developed and with regards to ageing the field of metabolomics (the study of all the molecules and pathways occurring within a cell/organism) holds great promise for the future.
     
    Last edited by a moderator: May 5, 2017
  8. Oct 28, 2011 #7

    Monique

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That's why scientists turn to much simpler organisms such as C. elegans to study longevity. We know too little about the subject (although I would say big progress has been made in recent years), controlling the genetic background and environmental factors is extremely important in order to elucidate the different factors.
     
  9. Oct 28, 2011 #8

    atyy

    User Avatar
    Science Advisor

    What is the "phenome"?

    What, btw, is the human "genome" anyway? Naively, I'd expect it to include the distribution of polymorphisms in the human population, which I don't think the orginally advertised "complete genome" had.
     
    Last edited: Oct 28, 2011
  10. Oct 31, 2011 #9

    Ryan_m_b

    User Avatar

    Staff: Mentor

    The phenome is the sum total of physical traits that an organism expresses. It is created by the interaction between biology and the environment (in such a vague, tangled way that it's almost impossible to tease out totally).

    I've heard them used interchangeably but the genome is the sum total of an organism's DNA (or RNA depending on what they are), when applied to a species it is the sum total of genes, promoters etc of that species. A genotype is the specific variation of a genome that an individual has. e.g.

    Genome of Species X

    Genes: A, B, C, D, E, F, G

    Genotype of Species X Specimen Y

    Genes: A1, B1, C2+C1, E3, F0, G1+G4
     
  11. Oct 31, 2011 #10

    atyy

    User Avatar
    Science Advisor

    After seeing "phenome" in your post, I looked it up, and to my horror, it is quite a mainstream term nowadays! I'm the sort of old fogey who can't come to terms with "metabolome", "lipidome", "connectome" .... I only accept "genome", having been brainwashed when I was young enough to think it a word:) I can kinda live with "proteome".
     
  12. Oct 31, 2011 #11

    Ryan_m_b

    User Avatar

    Staff: Mentor

    I like it. Biology is a complex thing requiring a holistic approach. Breaking it down into different systems is a good way to go :smile:
     
  13. Oct 31, 2011 #12
    I hope to return later to this topic of discussion but first off wanted to share with everyone the Glossary of Genetic Terms from the National Gnome Research Institute. I think it is a very valuable resource.:smile: Here are three terms by the NGRI:

     
    Last edited: Oct 31, 2011
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Scientists Examining DNA of Centenarians
  1. Junk dna (Replies: 10)

  2. Is DNA information? (Replies: 38)

Loading...