I have a breed where it is very common in first teeth for the large canines to be misaligned. I have seen a lot of litters from top breeders and my own using their dogs and never seen a litter where there are not. I only ever keep a pup whose teeth are fine as a pup for showing and breeding.
If the bite is good they nigh on 100% are OK for 2nd teeth.
I have a litter now of 10 and of course teeth are something you check for and I cannot believe that I have a bitch puppy with what I would describe as a slightly undershot mouth. The bite should be level or scissor. Both are accepted.
They are 6 weeks and I have read that with growth the bite may correct but has anyone else experienced this. I would not keep her for breeding of course but wondered generally about her. It is not badly undershot like sticking right out. Her large canines fit of course. The dog is a Champion so no  problem there so can't believe this. This is the one thing I would not expect as a problem.

If it's reverse scissor at 6 weeks it's only going to get more undershot with maturity because the top jaw stops growing sooner than the lower jaw. If she was slightly overshot then the possibility is that the mouth would correct with age as the lower jaw caught up.

I read an article about how many different genes are involved in jaw development - and oddly the top and bottom jaws are governed by different genes; in effect a pup can inherit the top jaw from one parent and the bottom jaw from the other!

The sire's mouth might be perfect, but what about his sire's or dam's mouth?

> I read an article about how many different genes are involved in jaw development - and oddly the top and bottom jaws are governed by different genes; in effect a pup can inherit the top jaw from one parent and the bottom jaw from the other!

That sounds really interesting. Do you have a link?

I just had a search of the bowels of my computer and found it!

thankyou very much

My first Bedlington bitch had a tight reverse scissor bite when I bought her.   The lower teeth were tightly outside the upper teeth.   Canines were correct and importantly, the lower jaw bone was correct.   It was simply the teeth. 

I had no intentions at that stage of showing or breeding so it wasn't a problem for me.   

The new teeth came through perfectly.    She was a Champion in a breed where teeth are examined and will hold a dog back if not right.  

We bred cautiously, choosing a dog with perfect dentition both as pup and adult, and from lines with perfect dentition.  

None of her pups ever had a problem with their puppy teeth or adult teeth,  nor  have  her grandpups.    I kept a bitch from the first litter and the rest went as pets, not to be bred from.   The same with the litter from my second bitch.

We did have expert advice from mentors in the breed regarding her lines and whether this was likely to be passed down.

The important point for our   breed was that the jaw bones were never in question,  it was simply a puppy tooth placement problem.

If you have mentors you trust in the breed, who have the knowledge and  experience to  help, it may be worth asking their opinion.   
The answer to this could be very different, depending on the breed, and the lines.

Hi
On the 6th April  we will have our "normal" puppy party where I will have lots of people here including the owners of the stud dog and other proficient people in the breed. At that point I will have finally chosen my puppy. The last comment has reassured me a bit. I still would not choose her as a precaution ( she is one of the bigger puppies and I would worry she may be a bit big for a girl. I was more concerned though about long term issues.
The teeth are all nice  and straight and are just inside. We are talking about a terrier breed.

I should also add that the litter on the sire's side come from a long line of Champion's and I have my line going back to Great Great Grandmother and have never seen this before. That is why I was so concerned. I will start asking a few questions of people closer to me who will be honest with me.