Archive by Author

Domestication

10 Jun

Beautiful isn't it?

Dogs have been companions to humans for a long time.  It is likely they were the first animal domesticated.  There is a great deal of speculation about how dogs became dogs.  We know that the dog started as a grey wolf, but since the change from wolf to dog happened in our distant past, we have very little to go on.

One theory is that wolf cubs were “adopted” by humans.  This theory points out that our dogs exhibit the behavior of juvenile wolves.  They have similar bark patterns and they wag their tails.  Later they were bred for those behaviors and for other more juvenile wolf appearances.

A scientist in Russia, who was trying to breed fur animals that were easier to handle, started an experiment on domestication.  He postulated that dog-like behavior could be bred for.  For more than fifty years,  Dmitri Belyaev led a project at The Institute of Cytology and Genetics at Novosibirsk that selectively bred silver foxes for the characteristic of being friendly with humans.

Over 35 generations, breeding for this one trait provided interesting physical results. The foxes that were bred for friendliness to humans, had shorter muzzles.  Their coat color changed.  The foxes came into heat every six months, instead of annual.  The list of changes that came from simply breeding for tameness is amazing.  And all of this happened over fifty years.

Examples of changes in coat color

More surprising, after a mere six generations wanted attention from humans.  They whined and licked hands, just like a dog.  Mind you, these foxes were only tested for these interactions once a month.  Otherwise, they were kept in cages as they were bred.  Just imagine, though, six generations and the foxes were demonstrating all the characteristics we expect from our dogs. 

At this point, very few of the foxes exhibited those traits.  By the twentieth generation, thirty five percent did.  According to the Institute now, more than seventy percent exhibit these domesticated traits. 

Research has show that the bred foxes have a longer period of time before certain stress hormones peak, which means that they have a longer period of time before they react to unknown stimuli with a fear response.  It is therefore easier to integrate them with humans.  There is also an overall decrease in adrenal activity.  The foxes are less inclined to have those fear responses.

Not all of these changes are promising results.  For one thing, while the vixens do come into heat every six months, not pup born out of season (not during the usual annual breeding cycle of January to March) has survived to adult hood. 

Domestic foxes are not dogs and not all of their domestic behavior is dog like.  They are said to be as friendly as dogs but as independent as cats. 

What else could come of this?  We may never know.  The domesticated breeding experiment is in constant jeopardy due to funding issues.  They keep themselves afloat by selling some stock to fur breeders who are looking for animals more content with captivity and selling others as pets.

You can purchase a domesticated silver fox from SibFox.  They’re expensive, but they have to be shipped from Russia.  An animal domesticated under fairly rigorous scientific conditions.  It is amazing to think about and consider how quickly an animal could be breed to fit in with humans.

Who could resist that face?

Not all animals could be domesticated in this way, but it provides us insight into how man’s best friend became that.

Advertisements

Green Glowing Things

22 May
You might have seen them in the news, along with the strange pictures.  Tales of Mr GreenGenes or glowing green mice.  It seems both frivolous and a little scary.  Why spend the time and resources making things glow green under ultraviolet light?
 
Green Flourescent Protein or GFP is used as a marker to detect for successful transfer of genetic material.  You attach the gene that makes GFP to the genetic sequence you are inserting into your subject.  After allowing your test organism time to begin to express the new sequence you added, you put the organism under florescent light and if it glows green you know it was a successful splice.  You can analyze the amount of the emissions or the total number of cells that glow to estimate success.
GFP is a real boon.  The genetic sequence that programs cells to make gfp is always turned on.  It is non toxic, for the most part, and requires only oxygen to begin expression.  In addition, the presence of GFP does not influence the expression of the protein sequence it is attached to.  The sequence has also been altered to allow for different colors as well.  Enough so that pictures like the on the right can be made from bacteria expressing the different version of gfp.  Basically, GFP is the perfect marker.

Since it does not inhibit or influence proteins when it is expressed with them, it can be used to monitor the function and flow of proteins within an organism,  Even while the cell is alive!  Before all the research with GFP, it was much harder to determine how proteins were used by cells. There is only so much information you can glean by putting something in a blender and measuring the amounts of what it is you are looking for.  So GFP allows scientist to watch how cells actually function.

So why the glowing cats and mice and other glowing things that really make the news?  Well, one reason is to show that we can and show that GFP functions inside a living organism.  Some of those glowing creatures were made glowing after they were already born, so they showed that organisms can have their genetic material changed without adverse effects.  Plus, making headlines is a good way to get people’s attention, including the attention of people who give money to science.

Research is expensive and genetic research can be hard to find funding for.  It tends to take a long time and the results are guaranteed.  Plus, lots of people, even die hard experimentalists like me can get a little squicked out by some of the possibilities. After all, I am not sure I want to have even a benign genetic sequence from a jellyfish attached to some of my DNA.

Dealing with Jargon

5 May

Right now, I am trying to construct a post about why CopyCat (CC) does not look like Rainbow, despite being a clone.  If I was doing it as a paper, it would have a title like “Phenotype differences in coat color in cloned female cats.”  It would be filled with details about x chromosome switching and genetic expression.  Are your eyes rolling into the back of your head yet?  And that is just a mild example of what things written in scientific journals can look like.

Jargon is important.  It helps makes things easier when you are talking to your peers about a subject where you both share knowledge.  When you are talking to someone who is outside that field, it will make their heads spin.  Knowing your audience is key to knowing how and where to use jargon.  When it comes to blogging, your audience becomes harder to know.  For my personal blog, I know that the majority of my audience is made up of my friends.  Since I know them fairly well, I know what to explain in detail and when I can just use jargon.  For the Divas’ blog, I assume that the audience is wider, which would require more explanation and less jargon.

You might hear some people call this “dumbing down.”  I really dislike that term.  I do not think people are stupid and I do not think I have to make science dumber for people to understand it.  Jargon in the sciences developed so that difficult and complicated subjects can be discussed without having to spend so much time describing each little thing every time.

The challenge for a science blogger is to find the right balance between overloading your audience and gutting the topic you are trying to explain. It is a struggle but I hope I manage to properly explain topics in a way that makes them nearly as interesting to me as to other people.  If nothing else, the struggle to find the balance keeps things interesting.

Cloning – You can’t always get what you want

19 Apr

Once upon a time, there was a millionaire that had a very old dog named Missy.  This millionaire loved Missy enough that he was willing to give money to scientists to make a copy of her. He started a project called Missyplicity in 1997 to fund research that would result in a clone of his beloved dog.  Missy died in 2002, but three successful clones were made of her in 2007 by the Sooam Biotech Research Foundation in South Korea.  According to reports, the clones of Missy look very much like her.

It took ten years to clone Missy and eight years to clone a dog successfully.  The project started at Texas A&M University.  It is not as strange a marriage as you might think.  In the minds of many scientists, cloning is the logical next step from controlled interbreeding.  Instead of breeding for the traits you want, you can clone the animal or plant you have that already has them.

Cloning a dog was more difficult than they thought, so to try and work out the kinks Texas A&M decided to try to clone a cat first.  Late in 2001, Texas A&M managed to clone a cat named Rainbow.  The clone, named CopyCat (CC for short), was the only one of 87 embryos that survived to term.

A University of California at Davis geneticist confirmed that CC is a clone of Rainbow.  Really, I promise the cat on the right is genetically identical to the cat on the left.  So why do they look so different?

It all has to do with how the coat color in cats is expressed, specifically the orange color in a cat’s coat.  The orange color gene ( referred to as O) is a sex-linked trait.  That means that the gene for orange color is on the x chromosome.  Females have two X chromosomes and male have an X chromosome and a shorter Y chromosome.  This is the reason that the overwhelming majority of calico cats are female.  (You do occasionally see male cats that are XXY, but I can already see that Bika is falling asleep, so I will skip that whole tangent)  A calico female cat has a genotype of Oo, that is it has a dominant gene for orange color and recessive gene for no orange color.

Now, basic genetics might lead you to think that an Oo cat would mean that it would be orange.  Since O is dominant, meaning that all things being equal, that trait drowns out anything else.  When it comes to coat color in cats, however, not all things are equal.  The activation or expression of genetic traits can vary.  In Calico cats, each cell either has an expressed dominant O or unexpressed.  This expression or lack of expression is believed to be influence by a number factors and is completely random.  And that is why Rainbow and CopyCat are exactly the same genetically but look completely different.