Blog Entry

Where did mitochondria come from?

Mitochondria, the powerhouses of the human cell, are passed to offspring only from the mother. Dad's mitochondria are used to propel those sperm toward the egg. Mitochondria have their own DNA, and their own system of replication and translation; they reproduce by simple binary fission. Sort of like a bacterium. That's why Lynn Margulis, in 1970, proposed that they--and chloroplasts--were independent organisms that genetically modified existing cells by taking up permanent residence in their hosts.

Click on Read more to see what they look like.

This photo was so beautiful, I couldn't pass it up. I took if from another source, which has not been updated since 2002. Don't know where it came from before that.

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Future uses of whole-genome samples and data

The final issues discussed in the article, Research ethics and the challenge of whole-genome sequencing focus on the fact that researchers, biobanks, companies that may fold tomorrow hold your DNA once you submit it for analysis. In signing an informed consent for your DNA to be sequenced, and maybe even for the information to be published publicly, you are giving up your autonomy. You--in the form of the genetic material that makes you who you are--now is available to others.

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Genome sequencing--obligations to close relatives

This is part 2 of the discussion of the issues raised in the Nature Reviews Genetics article, Research ethics and the challenge of whole-genome sequencing. The article itself is available only to those with library access or a journal subscription. As in earlier entries, quotations and indentations identify text taken directly from the article.

I wonder. . . did James Watson or Craig Venter ask their relatives whether they agreed to them having their whole genome sequence posted for the public to see? What about the 9 volunteers for the next public batch of genome sequencing?

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Genome sequencing--how are results reported?

What kind of data should be provided to those who have their genome sequenced?

This is the first issue raised by McGuire, Caulfield, and Cho in their Nature Reviews Genetics article, Research ethics and the challenge of whole-genome sequencing. In the following, I have taken their text and added some text of my own. The authors' text is in quotes or indented.

 "Should participants simply be given their raw sequence data?"

"James Watson received a miniature hard drive with his entire genome sequence. For most individuals, this form will be meaningless." Most of the rest of us are unlikely to be able to interpret a raw-data presentation. "People who consent to have their genome sequenced," whether for research or personal use, "are likely to want to learn more.""

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What is PGD?

We are often asked about PGD - what is it? who does it help? how does it work? This post will attempt to answer these questions at a high level. Individual questions are welcome and will be answered.

PGD (preimplantation genetic diagnosis) is a laboratory procedure that is used in conjunction with in vitro fertilization (IVF) to help detect certain diseases. Families affected by essentially any inherited disease can reduce the risk their offspring will suffer that genetic disorder by working with an experienced PGD team. Even families in search of a bone marrow donor may be able to use PGD to bring a child into the world that can provide matching stem cells. 20/20 recently ran a story on a family who chose this path (12/21/2006).

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Whole-genome sequencing--issues and recommendations

As regular readers of this blog know, I get alerts every day on genetic testing, gentics, etc. and read through those for ideas for this blog. I generally choose ones that are of interest to me and I hope to those reading Genetizen. Unfortunately, some of the alerts relate to professional publications which many of you cannot access. When this happens, I request a reprint from the corresponding author and give you as much as I can about the article..

An article titled, Research ethics and the challenge of whole-genome sequencing, an advanced online publication of Nature Reviews Genetics 18 December 2007 struck my I've-got-to-blog-about-this bone. Timothy Caulfield, one of the authors, was kind enough to send me an electronic copy of the full article. You can obtain the same yourself if you have access to a library that carries Nature Review Genetics, a subscription, or the authors e-mail address, which I will be happy to provide in response to comments on this blog. Because of copyright issues, I cannot simply post the entire article

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How to find specific blog entries

Because our organization is currently operating on no outside fundiing, we've chosen to keep our website simple. One loss, as far as I'm concerned, is the inability to search for specific blog entries using key words. I'm sorry that is the case. A search engine that is not flexible enough to find what you are looking for is worse, we believe, than nothing.

So, here's what you do if you are interested in a particular topic: click on the linkis at the left, by subject. There was only one entry in bioweapons--the blogger quit almost immediately, so that's not on the list. However, the other general topics are. They look really weird, you say. That's true, but for some programming reason I do not understand, such topic lists look weird on a number of sites--including those written by professionals who really know their html, etc.

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What will prostate genetic testing do for men?

I've written several times about women who have double mastectomies after learning that they carry a BRCA1 or BRCA2 mutation and, as a result, are many times more likely to develop breast cancer than women without one or both mutations.

The news in the past couple of days has been describing 5 genes identified as conferring risk of prostate cancer. Apparently the effects are additive in that one gene mutation alone is not enough to give increased risk.

None of the articles I have read indicates what men will do with the information if a test is developed and they learn of their increased potential for getting prostate cancer. Apparently the genes do not affect PSA (prostate specific antigen) levels, so there's no indication that the current standard test for prostate cancer would be helpful.

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Government DNA databases--who's targeted?

The retention of millions of innocent people's DNA raised "significant ethical and social issues" in the United Kindom, which has launched an inquiry into the way the national DNA database is used.

According to an article in the BBC news,

Since 2004, the data of everyone arrested for a recordable offence in England and Wales--all but the most minor offences--has remained on the system regardless of their age, the seriousness of their alleged offence, and whether or not they were prosecuted.

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Studying the function of the BRCA2 gene

Thousands, perhaps hundreds of thousands, women have had a genetic test for the BRCA1 and BRCA2 mutations association with higher risk for breast cancer. So far, it's been difficult to determine exactly what the genes do in humans, other than interfere with the function of two suppressors apparently needed to properly manage DNA replication and repair.

A recent article in PLOS Genetics, an open-access, peer-reviewed online journal, describes some experiments that have been conducted with the common fruit fly, Drosophila melanogaster, which also has a BRCA2 gene. The article is titled "Drosophila brca2 is Required for Mitotic and Meiotic DNA Repair and Efficient Activation of the Meiotic Recombination Checkpoint" and the abstract reads as follows:

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