Between the intro and the PHD

What sort of genetics? Just coat colour genetics or all of it? Biological science text books usually have some genetics info so maybe pick a level you want to study at and look at one of them?

The principles of genetics, the specifics of colour genetics. I have an A level in biology and did reproduction and genetics at degree level so I have the basics well down its getting into what exactly is a microsattelite marker? and what does it do? and where do I now find out what all the other words and acronyms that where used in that definition mean?

Maybe get a BSc level genetics text book? I have one that I got for my degree, some of it whooshes over my head but some is good.
Try putting the term you want to know about into Wikipedia (I know its supposed to be untrustwothy but I reckon there are enough pedants in the world to mean its really pretty accurate at least for basic explanations plus there are often good links too), there is a page for microsatellite markers on there. Thats what I did when I did my degree, get the basic info from Wiki which gave me a base for reading more in the text books.
You are unlikely to find much on colour genetics outside of genetics journals.

Thanks for the reply :) I will check out wiki. I have had an instinctive avoidance to it because of the number of times my lecturers told me NEVER to reference wiki but it could be useful for definitions.

College level genetics textbooks are probably your best bet. "An Introduction to Genetic Analysis" is always a good one.

A microsatellite marker is a type of genetic marker that's used in mapping genes. They are repeated elements in the DNA that are found throughout the genome. The repeats are most commonly two base pairs (these are called "dinucleotide repeats")...this would look like, for example, GTGTGTGTGTGTGTGTGTGTGTGTGTGTGT. That's a GT(13) microsatellite. (The GT is repeated 13 times.) You can have trinucleotide microsatellites and even tetranucleotide microsatellites, but they are less common.

Microsatellites make great genetic markers because they're extremely variable. An msat may have only 8 or 9 repeats, but can have 30 or more (very long!). When DNA polymerase tries to copy these repeats in our genome, it often gets confused (am I on repeat 10 or 11?) and will often add an extra repeat or take one out. The longer the repeat, the more often this happens. So different people, or horses, or dogs, or whatever, start to get different alleles of msats just like anything else. At one particular msat, a horse may have one copy that has 14 repeats, but the other copy has 17. These are inherited from the parents like anything else. The more variation the msat has in a population, the more "polymorphic" it is, and the better marker it makes.

Microsatellites don't "do" anything. They're found in regions of the genome that are considered "junk". That's why organisms can tolerate all the errors in them. We use them primarily for two reasons--one is parentage verification. When you send your foal's hair in to be tested against his sire and dam, the lab has a panel of microsatellite markers which are very polymorphic. The check your foal's type (say, 14 repeats and 17 repeats) against his dam (say, 16 repeats and 17 repeats) and his sire (say, 14 repeats and 17 repeats). They do this for lots of msats (UC Davis uses about 16 initially, I think) to tell you whether your foal qualifies to both parents. For example, if your foal's listed sire had 16 repeats and 18 repeats, he would be excluded.

The other thing we use them for is genetic mapping of traits. Often, when we're looking for a trait of interest like a coat color or a disease, we type a family of horses segregating for the trait with hundreds and hundreds of msats all over the genome, and we look for linkage between an msat and the trait. If a stallion has a coat color A that we want to map, and is heterozygous for that coat color, we can use him for mapping. If we find that every time a foal gets the coat color A, he gets 14 repeats from his sire, and every time he gets coat color B he gets 16 repeats from his sire, that tells us that the coat color gene is somewhere close to that microsatellite. That's mapping!

:D Thankyou very much horsegen - do you teach? because you really are fantastic at making things understandable.

I lecture often, but just finished my Ph.D. and am now in a postdoctoral fellowship that is designed to prepare me for a university teaching position. I love to teach and it has always been my goal...I just had to put in my time behind the lab bench first! Hopefully I'll move into a full-time teaching position in the next few years...right now, I develop curriculum for the genetics department at the Harvard Medical School.

"I develop curriculum for the genetics department at the Harvard Medical School." *faints* Holy cow... talk about a prestigious position!!

Oh, I know, it sounds pretty chic. It's actually a lot of fun...there are a number of curriculum fellows here, each of us in charge of curriculum development/improvement for a certain program. I'm the fellow for genetics, but we work together on a number of things as well. Our job is to improve or enhance existing courses, either by figuring out how to broaden the content of the course or helping the professors with ideas on how to better teach the concepts. We also develop smaller "nanocourses" designed to give students an in-depth look at topics of interest over a period of two days, and we often organize and run "boot camps" for first-year graduate students which give them an opportunity to spend several weeks in the research labs of our departments. Eventually I will develop and teach my own courses through Harvard Extension.

It's a great program, designed to be a post-doctoral position that focuses on preparing Ph.D.'s to become teachers, as opposed to researchers. Perfect for me! Also, I'm working to insinuate horse genetics into as many courses as possible, and I give lectures on the topic to graduate students. It's all part of my evil plan to have horse genetics take over the world! :twisted: