DNA of a specific beed. (Also in veterinary)

[diamondgeezer]

Hello!

I have just been having a conversation with a friend and we are now confused!!

Does each breed of horse have a specific gene? for example do all TB's have the TB gene and all shetlands have a shetland gene, so to speak.

If so why is there so much confusion over DNA testing to see if a certain horse is of a certain breed.

any help to clear this would be great!
__________________

 

[Vixen Van Debz]

It would take a body of genes (e.g. guiding their height, build, metabolism, coat colour etc) to make a specific breed what it is, then meaning that testing for a breed would be difficult precisely because there is not one single, unique gene that guides its specifics. (There may be the occasional exception for extremely rare traits e.g. tolting). It'd be like forensically examining a cake to find out which type it was, but finding it hard to work out because like every other cake that's been tested, it all seems to be the same sugar, egg, flour mix, making it hard to differentiate. Hope that makes sense outside of my own head!

 

[SusannaF]

Nope! We need JessTickle along to give a better explanation than I could give, but nope.

Przewalskiis have a different number of chromosomes to domestic horses, which may or may not mean that domestic horses are not descended from Przewalskiis. The genome for domestic horses has been sequenced though:

http://www.sciencedaily.com/releases/2009/11/091105143708.htm

The diagram for it is pretty amazing. You see how certain breeds are the ancestry of others (ie Exmoors for TBs).

 

[diamondgeezer]

ah thats brill, Thanx

Its all very confussing but the cake explanation was fab, understood alot better from that!!

Thank you both for your time!