Tag Archives: Genetics

IoD – Genetic Engineering Vows

Posted by vidyant on July 26, 2011 No comments

Genetic Engineering Vows
Genetic Engineering Vows

Genetic Counseling is the way of the future.  It is already common to match couples in some populations in which some hereditary diseases are common.  For example, the Ashkenazi Jews have a high incidence of Tay-Sachs disease (1 in 27 compared to 1 in 250 in general population), which is an autosomal recessive disease.  If both parents are carriers, then their child has a 25% chance of having the disease, which is fatal and can lead to death by the age of four. So organizations like Dor Yeshorim perform genetic tests on couples to assess the risk of their progeny having Tay-Sachs and other commonly inherited diseases in the Jewish population.  If the risk is high, the common recommendation is to avoid having children.  This approach has been quite successful and has greatly reduced the incidence of Tay-Sachs in Jews.

On a less serious side of things, University of California Berkeley, my alma mater, started a program called “On the Same Page”, which each year attempts to engage new students in an intellectual exercise focused on a particular topic.  Part of this program included a voluntary genetic testing program for incoming Read more »

Should Rosalind Franklin be given a posthumous Nobel Prize?

Posted by vidyant on July 25, 2011 4 comments

One of the greatest minds and scientists ever to have lived was born today on July 25, 1920. Her name was Rosalind Franklin and her X-ray diffraction images of DNA were paramount in elucidating the double-helix structure of DNA. Without her contributions, Watson and Crick, or Linus Pauling for that matter, may never have been able to figure out the structure of DNA.

Rosalind Franklin
Rosalind Franklin

It was Franklin’s insistence on getting better and better pictures, her unwavering belief that in order to represent reality DNA samples must contain high water content, her conclusion that sugar phosphate chains had to be on the outside and bases on the inside of the DNA molecule, and of course her phenomenal X-ray images that made solving the mystery of DNA structure possible.

Admittedly her contributions were second to none but it would be wrong to say that Watson stole her data, as some claim. She, in Watson’s account of the discovery in The Double Helix (probably the greatest science memoir ever written!), was very Read more »

Transformation vs Transfection

Posted by vidyant on February 10, 2011 2 comments

“What is the difference between transformation and transfection?”

Not much, really. Although it’s not just a matter of semantics, the difference is very subtle.

Transformation in cloning is the process in which a cell “takes up” exogenous DNA from its surroundings through its cell membrane. If the cell later goes on to express this uptaken genetic material, it is said to be transformed. However, the term transformation in this sense is restricted only to Read more »

Miniprep in detail

Posted by vidyant on February 8, 2011 4 comments

Lucky you! You saw colonies on your transformation plates, your bacterial cultures are nice and cloudy, and you are ready to isolate your plasmid! You are so very excited because you finally get to play God and kill all those pathetic little bacteria that you cleverly manipulated into expressing your gene. So, you go over to the stock room and buy yourself a Miniprep kit – with your PI’s money, of course.

There is no compelling need for actually buying the kit because you could make all the buffers and solutions in lab; that is, if you wanted to waste incredible amounts of your time, effort, and precious brain cells. Truth is that nobody likes to make buffers, especially if it requires optimization of pH. Ugh! So why not use the kit? After all, it comes with pre- made buffers and a handy protocol that works like a charm.

The problem is that you mindlessly read directions from the protocol without ever thinking about the composition of buffers and what the different components accomplish. Isolating a plasmid is, in fact, a very elegant chemical process. Read more »

Aberrant Chromosomal Rearrangements in Cancer

Posted by vidyant on December 29, 2008 26 comments
Chromosomal Rearrangements (adopted from Hampton, Hollander, Miller et al. 2008)

Chromosomal Rearrangements (adopted from Hampton, Hollander, Miller et al. 2008)

Yesterday, I was just browsing through the internet and stumbled upon a really interesting article called “The Chaos Inside a Cancer Cell” in New York Times in the science section.   Naturally, it grabbed my attention because of my immediate interests in cancer genetics but the article was just a brief overview with very few details so I decided to venture a bit deeper and dug up the actual article from Pubmed.  It is available for free so everybody can view it if you so decide.

Now, obviously the reason I am writing this post is to let you in on some of the details of this beautiful paper and spare you some of the complexities.  On that note, let me get started.  The article explores genomic aberrations in MCF-7 breast cancer cell line derived from a 69-year old Caucasian woman in 1970 who underwent two mastectomies.  Many researchers choose this cell line because it has been very extensively researched and documented upon, making it a good research model.

As you may know, one of the common characteristics of a cancer cell is its uncanny ability to survive. ‘Normal’ cells have a biological clock and they have a mechanism to self-destruct called apoptosis. But cancer cells do NOT. Additionally, if DNA breaks or damaged DNA are not corrected, it is often a signal for the cell to kill itself but cancer cells can surpass that checkpoint.  It is also pretty widely accepted now that chromosomal instability leads to tumorigenesis.  These are basically genetic mutations that either enhance cell survival or proliferation. In all, it makes studying cancer genomes of obvious interest relative to normal genomes to understand their unique survival and/or proliferative advantage. Read more »

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