Stories tagged genetics

Jun
09
2007

The answer to the question posed by the title of this entry is, of course, “yes.” There are many things fruit flies can’t do: they can’t roller-skate, they can’t drink a Pepsi in under 30 seconds, and they can’t get into an argument without resorting to foul language (trust me on this). There are other things they can’t do, but these are the main ones. And, until recently, “provide clues on inhibiting aging” was also on this list, but that may have changed.

Scientists at the University of Southern California (which happens to be the anti-aging capital of the world) have discovered that a single genetic change engineered in fruit flies can extend their life spans by a third, with no apparent side effects.
My mutant power? Eternal youth.: If we could only be a little more like them.
My mutant power? Eternal youth.: If we could only be a little more like them.

The scientists found a way to block certain cell receptors (areas on cells that transmit signals across the cell membrane) associated with aging and disease. Cells were bombarded with peptides (short proteins) until the researchers found a group that would bind to the aging-receptors, blocking them. Fruit flies were then genetically engineered to produce these specific receptor-blocking peptides. I don’t really understand this part of the process, but it involves getting the peptides to replicate the same way DNA replicates by fusing these peptides to RNA. At any rate, these flies did indeed live longer.

The technique could, hopefully have applications in treating human diseases – once specific disease-related receptors were located, scientists could go through their library of peptides until a group was found that bonds to the receptors. Some of us maintain hope, also, that our DNA might be altered so that it reproduces not just receptor-blocking peptides, but rad things like fireballs and adamantium claws. Scientists have odd priorities, though.

Fruit flies with mutant healing powers.

Jun
02
2007

Walt Disney’s dream has finally become nightmare-reality.
I don’t think that statement needs any clarification, but for those of you who are unwilling to accept what’s in front of your very eyes, let me lay things on the line: Scientists from Texas (of course!) have genetically engineered super mice.
Our Only Defence: Keep these close at hand. They may be our only hope. (photo credit to billselak)
Our Only Defence: Keep these close at hand. They may be our only hope. (photo credit to billselak)

What are coming to be known as the “six million dollar mice” (and I can not confirm that price tag, only that they are indeed as cute as the original six million dollar creation, if significantly smaller than Lee Majors) were created by the genetic deletion of the enzyme “Cdk5” from their mousy brains. This causes “an increase in sensitivity to their surroundings” which “seems to have made [the mice] smarter.”

The smart-mice have become more adept at learning to navigate through mazes, and working out new routes as the mazes change. They also are able to quickly learn that “being in certain boxes involves a mild shock.” These are things that I can’t even do, and I have a degree in English.

As horrifying as the prospect of a genius mouse may be, the Texan scientists are quick to point out aspects of their research that will likely be beneficial to human health and psychology.

The technique used to suppress the Cdk5 enzyme works at the genetic level, and is referred to as “conditional knockout.” It allows scientists to eliminate the gene only in the brain, and only once the subject is an adult, as opposed to the older and less sophisticated “traditional knockout,” which eliminates the gene entirely.

This sort of therapy might be used to help people suffering from conditions such as post-traumatic stress disorder “learn that a once-threatening situation no longer poses a danger.” Also, Cdk5 seems to be associated with drug addiction and Alzheimer’s disease, and the researchers are hopeful that the study might lead to further treatments for these and other conditions.

So, we may not be doomed to some kind of Mickey Mouse/Bladerunner-esque future after all, but, still, I’ll be keeping my eyes and puny human brain trained on this one.

An article about the smart mice

Apr
10
2007

Let me be your little dog till your big dog comes: Science unlocks the genetic secrets of dog size.
Let me be your little dog till your big dog comes: Science unlocks the genetic secrets of dog size.Courtesy Rollinho

Every dog on the planet, from the tiniest Chihuahua to the largest Great Dane, is a member of the same species. Yet they vary in size tremendously – more so than any other mammal. Scientists have finally figured out why.

A researcher at the University of Utah has discovered a tiny piece of DNA in the dog genome that shuts off the production of growth hormones. It affects a gene called IGF-1, which also exists in humans. For us, it not only regulates growth, but also plays a role in cancer and some bone disease. Learning how this gene works in dogs can be a first step towards treating these diseases in humans.

Feb
20
2007

Drugs manufactured in eggs and milk.

Drugs from goat milk
Drugs from goat milk
Farm animals are being modified genetically to produce milk and eggs containing pharmaceuticals. Just after ferilization "Pharmers" insert into the embryo human genes for producing proteins needed to treat humans unable to produce their own. They attach that DNA code with a gene that codes for a sugar found in milk. The therapeutic protein will then be produced within the animals milk.

Pharm animal drug approved

GTC Biotherapeutics anti-clotting agent, ATryn, is the first government-approved drug from transgenic animals. It replaces human protein antithrombin, which helps prevent blood clots that could lead to a stroke or heart attack. About one in every 5,000 people has a genetic deficiency of this protein. One goat can produce a kilogram of antithrombin each year. It would take 50,000 people to donate that same amount.

Chickens can lay medicinal eggs

Chickens can also be modified to produce human proteins in the albumen of their eggs. Origen Therapeutic scientists hope to breed a chicken that will produce the entire range of human antibodies in its eggs.

Source article: Wired.com

Feb
14
2007

Help! Patent attack.: Somebody patented my face and I can't get it off.
Help! Patent attack.: Somebody patented my face and I can't get it off.

For once I agree with Michael Crichton. Allowing companies to hold patents on parts of the human genome is a very bad idea. Crichton wrote a great editorial in Feb. 13th's New York Times illustrating why human gene patents are such poppycock. It is a short read but it really got my blood boiling.

I was surprised to find out that one-fifth of the the human genome has already been patented by companies in the US. But a couple smart politicians, Xavier Becerra, a Democrat from California, and Dave Weldon, a Republican from Florida (yes Gene, I do think science and politics should mix) are introducing legislation that will stop this.

“We seek simply to fix a regulatory mistake,” Rep. Becerra said. “Genes are a product of nature; they were not created by man, but instead are the very blueprint that creates man, and thus, are not patentable. Gene patenting would be the analogous equivalent to patenting water, air, birds or diamonds.

Some people think that patents cause competition between companies that results in more active research. While others think that human gene patents actually inhibit research and are morally wrong. Tell us what you think below or vote in our poll, Should companies be able to patent human genes?

More resources:

Nov
15
2006

Late last month, fishermen in Japan netted a surprise -- a bottlenose dolphin with two well-developed rear flippers. The flippers are remnants of the legs which grew in the dolphin's prehistoric ancestors.

Every animal's body is built by the genes contained in its DNA. But not all genes are active -- they have to be turned on by controller genes.

Over time, the DNA in a species changes -- new genes emerge, old ones become inactive. But in many cases, the old ones don't completely go away. The controller changes and stops activating the gene. But if there's a change in the controller, it may activate that forgotten gene again.

(The same thing happens with humans. As a baby develops inside its mother, it grows gills and a tail -- remnants of our animal heritage. These disappear before the baby is born.)

Jun
05
2006


Should we engineer our babies?

Genetic testing is allowing us to determine more and more information about the health and characteristics of our babies while they are still in their mothers' wombs. With this heightened level of awareness and power, we have to ask ourselves some pretty tough ethical questions:

  • Can we cure deafness or Down Syndrome through testing? Should we?
  • Is not having babies with a known trait an ethical way to eliminate that trait in our population?
  • Should we be able to select for "positive" traits or select the sex of our babies?

I attended an interesting film and discussion at the Bell Museum last week that focused on many of these issues.

Who's Afraid of Designer Babies? is a documentary mostly following several Australian families grappling with a wide array of genetic issues, from crippling genetic illnesses in their children to more frivolous interest in selecting the sex of their children.

While the discussion was very intelligent and not overly polarized I can say that we were far from a consensus on many of these issues. These are complex issues that we will have to keep hashing out as the technology and social mores change. Haven't formed an opinion yet? Read below for more information.

Resources and Links

Genetic Testing & Screening at the University of Minnesota's Center for Bioethics - This is a great resource on the basic questions of ethics that come up around genetic testing.

Genetics and Public Policy Center - "The Genetics and Public Policy Center is a source of accurate and trusted information about public policy related to human genetic technologies and is supported at the Berman Bioethics Institute of Johns Hopkins University by The Pew Charitable Trusts." This group does allot of work in assessing public opinion on these issues.

The US President's Council on Bioethics - This group advises the president on the science and ethical issues behind policy and regulation of biological activities. In the recent past this group has taken a more conservative focus, with President Bush firing several of the more liberal members of the group who actively criticized his position on Stem-cells.

May
08
2006


Brassinosteroids in tobacco plants: The level of brassinosteroids regulates both the size and aging of tobacco. With low levels, tobacco is dwarfed (some as small as 10 inches tall; see plant in front) and the leaves do not age, while at normal levels of brassinosteroids, tobacco stands almost 6 feet tall and the leaves turn yellow as they age (plant in back). Photo courtesy Michael Neff and Joanne Chory.

I am all over this idea. While I don’t personally mind mowing, I know lots of people do, and truthfully, while I don’t mind, I sure would like the additional free time!

In a paper in the May 4 issue of Nature, scientists from the Howard Hughes Medical Institute report that they have figured out a class of hormones that regulates growth in plants – including grass! And while this would be great for me, there are a lot of other good things that could come of this besides a mow-free yard, such as the development of trees that could be halted at a specific height so that they don’t interfere with power lines, raspberry bushes grown taller so that they are easier to pick, and increase the yields of crops such as corn or soybeans.

The key hormones are called brassinosteroids. With this new knowledge regarding brassinosteroids scientists may be able to stop growth in yard grass by limiting brassinosteroids or increase the yield of a crop by increasing brassinosteroids. Increasing crop yields would be very useful, especially considering urban expansion and the loss of farmland worldwide and steadily increasing global populations.

I can’t wait until the mow-free lawn becomes a product – but we’re likely many years away from that happening. Until then, I’ll keep mowing – or just replace my lawn with Field Turf.

Dec
09
2005


Tasha the boxer: Tasha, the boxer whose DNA was sequenced. Photo courtsey of the National Institute of Health

A few days ago scientists from MIT and Harvard released the genomic sequence for the dog.

Previously, genomic sequences for mice, rats, bees, cows, mosquitos, fruit flies, sea urchins, humans, and chimpanzees, as well as several viruses and bacteria have been completed.

Studying genome sequences helps scientists understand how genes work together to direct the growth and health of an organism. Considering the cost and time involved - the dog sequencing took over two years and over $30 million to complete - making the right choices about what species to sequence is an important question. Researchers at the EMBL-European Bioinformatics Institute are proposing a system to determine what organisms should be sequenced next.