Linebreeding and Inbreeding
Let’s talk about Inbreeding, Linebreeding and Outcrossing!
There is a negative stigma associated with inbreeding, but very few understand the differences between inbreeding and linebreeding, and many associate the term outcrossing with mixing breeds. When done correctly, all 3 practices are valuable breeding tools!
Let’s briefly touch on the general purposes of each:
Inbreeding- inbreeding is used to “set” or “lock in” the good genetic traits of a specific dog or dogs. These can be physical traits or behavioral traits. Inbreeding is used to amplify those desirable traits and (hopefully) quickly create a program of superior animals.
Inbreeding should be done only with excellent dogs who possess a majority of the traits a breeder is looking for. Rapid improvement can be quickly made with inbreeding, but it can also expose genetic weaknesses in those lines. Inbreeding over time can cause a decrease in fertility and lead to a weakened immune system, generally known as inbreeding depression. In short, inbreeding exposes the bad traits while amplifying the good ones!
Linebreeding- linebreeding is used for the same purpose as inbreeding but is generally done over multiple generations, and is a slower process. Linebreeding is used when a breeder wishes to increase the influence of an outstanding animal within a select gene pool without tightly inbreeding. A dogs genetic contribution decreases by half with each generation*- its puppies carry 50% of its genetic material, it’s grand puppies carry 25%, it’s great grand puppies carry 12.5%, and so on; by the 7th generation, that dog is only contributing less than 1% to its descendants. By thoughtfully applying linebreeding to a program, a dog can be bred to its great grand puppy, increasing its genetic contribution from 12.5% to 62.5%, thus reintroducing and solidifying traits that may have been diminishing after several generations.
Outcrossing- outcrossing is the practice of breeding two animals together who have no common ancestors in at least 5 generations. Outcrossing is used to increase genetic diversity, introduce new physical and behavioral traits, decrease undesirable traits and decrease the effects of inbreeding depression and the genetic disorders that can result. While outcrossing can be used to decrease undesirable physical and behavioral traits, it can also decrease positive and desired traits.
*this is average- in the first generation the contribution is always 50%, but in successive generations there is limited percentage range.
•image sourced from IR-Ranch Dairy Goats
Sources: https://www.fao.org/3/x3840e/x3840e06.htm
https://onlinelibrary.wiley.com/doi/10.1111/jbg.12330
There is a negative stigma associated with inbreeding, but very few understand the differences between inbreeding and linebreeding, and many associate the term outcrossing with mixing breeds. When done correctly, all 3 practices are valuable breeding tools!
Let’s briefly touch on the general purposes of each:
Inbreeding- inbreeding is used to “set” or “lock in” the good genetic traits of a specific dog or dogs. These can be physical traits or behavioral traits. Inbreeding is used to amplify those desirable traits and (hopefully) quickly create a program of superior animals.
Inbreeding should be done only with excellent dogs who possess a majority of the traits a breeder is looking for. Rapid improvement can be quickly made with inbreeding, but it can also expose genetic weaknesses in those lines. Inbreeding over time can cause a decrease in fertility and lead to a weakened immune system, generally known as inbreeding depression. In short, inbreeding exposes the bad traits while amplifying the good ones!
Linebreeding- linebreeding is used for the same purpose as inbreeding but is generally done over multiple generations, and is a slower process. Linebreeding is used when a breeder wishes to increase the influence of an outstanding animal within a select gene pool without tightly inbreeding. A dogs genetic contribution decreases by half with each generation*- its puppies carry 50% of its genetic material, it’s grand puppies carry 25%, it’s great grand puppies carry 12.5%, and so on; by the 7th generation, that dog is only contributing less than 1% to its descendants. By thoughtfully applying linebreeding to a program, a dog can be bred to its great grand puppy, increasing its genetic contribution from 12.5% to 62.5%, thus reintroducing and solidifying traits that may have been diminishing after several generations.
Outcrossing- outcrossing is the practice of breeding two animals together who have no common ancestors in at least 5 generations. Outcrossing is used to increase genetic diversity, introduce new physical and behavioral traits, decrease undesirable traits and decrease the effects of inbreeding depression and the genetic disorders that can result. While outcrossing can be used to decrease undesirable physical and behavioral traits, it can also decrease positive and desired traits.
*this is average- in the first generation the contribution is always 50%, but in successive generations there is limited percentage range.
•image sourced from IR-Ranch Dairy Goats
Sources: https://www.fao.org/3/x3840e/x3840e06.htm
https://onlinelibrary.wiley.com/doi/10.1111/jbg.12330