I had a Basset Hound growing up. His name was Useless, Useless S. Grunt. Well, actually it was formally Ulysses S. Grant because the US Kennel Club wouldn’t accept Useless S. Grunt as a name as they felt it was too demeaning. Not sure if they felt it was demeaning to the dog or to the president, but that’s neither here nor there is it?
So,you ask, what made me think of that long-passed sweet dog that tripped over it’s too-long ears with it’s too-short legs? It turns out that they found out what genetic cause there was for those short legs in Basset Hounds (and Dachshunds and other breeds).
As NHGRI’s press release states:
In a study published in the advance online edition of the journal Science, the researchers led by NHGRI’s Elaine Ostrander, Ph.D., examined DNA samples from 835 dogs, including 95 with short legs. Their survey of more than 40,000 markers of DNA variation uncovered a genetic signature exclusive to short-legged breeds. Through follow-up DNA sequencing and computational analyses, the researchers determined the dogs’ disproportionately short limbs can be traced to one mutational event in the canine genome – a DNA insertion – that occurred early in the evolution of domestic dogs.
The insertion turns out to be a retrogene, which of course I also find interesting in that I studied retrotransposable elements. Reverse transcriptase has this habit of reverse transcribing RNA into DNA which can get reinserted back into the genome (hence processed pseudogenes of course).
The study is interesting for two reasons (other than because I had a Basset Hound and studied the evolution of retroelements ;), it gives us a further clue into evolutionary events that lead to large changes in morphology and the role of retrotranscription and it gives us a clue into possible human conditions.
For more about dog genome, you can read our several posts about the dog genome, go to NCBI’s dog genome home site (or UCSC or Ensembl and other browsers) and read the paper (needs a subscription of course, it’s in Science). It’s an interesting read so far (I want to find some time to read it more fully, perhaps Useless doesn’t live up to his name.. he didn’t really even then :D).