Question on line-breeding551

Question on line-breeding

View previous topic View next topic Go down

Question on line-breeding

Post by [Dino] on Tue Apr 10, 2012 6:11 am

I don't know if I'm posting this in the right section, but here goes;
Usually line-breeding means that you don't use directly related mice such as parent x offspring and brother x sister, but other relations are fine to use (nothing above 12.5% inbreeding coefficients), but when you keep breeding cousins together, doesn't the inbreeding coefficient keep getting larger? I have no idea on how to calculate this, I have found allot of ways to do so, but non of them make any sense to me Sad
What I mean by breeding cousins together;
Starting with unrelated mice, 2 males and 2 females, thus making 2 couples. Keeping one buck and one doe from each litter and then breeding the buck from one litter to the doe from the other litter (twice), so still not related. Then again keep 1 buck and 1 doe from each litter and mating them like previously and going on like this. Make any sense?...

[Dino]
Fuzzy
Fuzzy

Posts: 71
Join date: 2012-04-05
Location: Belgium

http://dino-s-wonderful-creatures.webnode.nl

Back to top Go down

Re: Question on line-breeding

Post by Mrs. Beach on Tue Apr 10, 2012 12:25 pm

All I can contribute is mathematical probability. If you have a 50% chance of one thing and a 50% chance of another, the chance they will overlap and happen at the same time is 25%, which is 50% of 50%. Just multiply the percent chance of probabilities together and you will see that the longer you breed in, the lower the percent chance becomes.

Now, this is theoretical mathematics. It may be different in actual mouse breeding application. I bet Stina can answer this question very well.

Mrs. Beach
Show Mouse
Show Mouse

Posts: 1074
Join date: 2012-01-12
Location: Silver Spring, MD

http://mrsbeachsbrindleempire.tripod.com

Back to top Go down

Re: Question on line-breeding

Post by Love2read on Tue Apr 10, 2012 12:42 pm

Yes, the COI's will go up with each linebreeding you do. You can pair 2 mice together with a 0% COI, but if they were, for example, brother/sister, then their babies' COIs would be 25%. If you then paired 2 of their babies together the COI would go up even higher(I think 32%, but I'm not 100% sure off the top of my head) and so on.

For my mice I'm not concerned with COI's because I breed for health and temperament and if I get an unhealthy mouse I cull the mouse and stop breeding the parents. If I get multiple defects/health issues in a particular line I'll stop breeding that line altogether. I think most breeders follow that standard.

That being said, COI's simply represent the percentage of chance that 2 animals have of carrying the same recessive genes that might cause problems, such as hereditary heart conditions, immune deficiencies, or even genes that cause tail kinks and other deformities. Just because a mouse has a low COI doesn't mean that they won't have any problems pop up and just because a mouse has a HIGH COI doesn't mean that problems WILL pop up.

With mice it can actually be beneficial to inbreed/line-breed because it helps to bring out those hidden genetic issues so they can be removed early and only the healthiest mice will be bred. Labs will actually inbreed their mice 20+ generations to ensure the purity and uniformity of their mice because they can't risk there being any hidden issues that might effect their results. If you inbreed mice multiple generations, removing any mice that have health issues or produce babies with health issues along the way, your end result with be very healthy mice with little or no potential risk of having recessive health issues.

Anyways...if you're still wanting to find out about COI's in your pairings you can use Breeder's Assistant. They offer a free trial program with no time limit, only a space limit(as to how many entries you can make). It will calculate the COI for you.

http://www.tenset.co.uk/fk19/ba-generic-download-demo.pl

Just fill out the form and they'll give you access to the download. I use the Generic one for my sugar gliders to ensure that the pairings are safe(I don't breed anything above 2% COI when it comes to my gliders).

Love2read
Hopper
Hopper

Posts: 275
Join date: 2012-02-09

http://www.justforfuzzies.com

Back to top Go down

Re: Question on line-breeding

Post by Rhasputin on Tue Apr 10, 2012 2:33 pm

Roland is also a very knowledgeable person to talk to about inbreeding and line-breeding. Happy


Rhasputin
Adult
Adult

Posts: 789
Join date: 2012-01-08
Location: Rochester NY

Back to top Go down

Re: Question on line-breeding

Post by [Dino] on Tue Apr 10, 2012 4:03 pm

Very helpful indeed! So if I were to select very severely on health the inbreeding doesn't matter that much Happy

[Dino]
Fuzzy
Fuzzy

Posts: 71
Join date: 2012-04-05
Location: Belgium

http://dino-s-wonderful-creatures.webnode.nl

Back to top Go down

View previous topic View next topic Back to top


Permissions in this forum:
You cannot reply to topics in this forum