Tuesday, September 26, 2023
Mitochondrial Health

Breeding Patterns: Lines, Clans and Mobs. Breeding and Genetics for Small Farms Part 3

Greetings! This is the third in the breeding/genetics for small farms series, and in it we will discuss the details of Line breeding, clan/family/spiral breeding, and mob/random breeding! The discussion is a compare and contrast covering the details of each method, what each does well, and where each fails. This video is intended to provide of survey of the main breeding techniques in common use, but the constraints of time do force simplification, and while this will help you understand and choose the best method for you and your farm, further study will be needed to execute said method properly. Since this is the third instalment and it leans heavily on the fundamentals presented in the first two videos, here is a link to the playlist containing them!

Citations for the discussion of the soay sheep and white park cattle feral populations (Just a sample, these are well studied populations and there is a lot more than just these few articles!):

Coltman, David W., et al. “Parasite‐mediated selection against Inbred Soay sheep in a free‐living island population.” Evolution 53.4 (1999): 1259-1267.

Gulland, F. M. D. (1992). The role of nematode parasites in Soay sheep (Ovis aries L.) mortality during a population crash. Parasitology, 105(3), 493-503.

Hudson, G., Wilson, I., Payne, B. I., Elson, J., Samuels, D. C., Santibanez-Korev, M., … & Chinnery, P. F. (2012). Unique mitochondrial DNA in highly inbred feral cattle. Mitochondrion, 12(4), 438-440.

Leivesley, J. A., Bussière, L. F., Pemberton, J. M., Pilkington, J. G., Wilson, K., & Hayward, A. D. (2019). Survival costs of reproduction are mediated by parasite infection in wild Soay sheep. Ecology letters, 22(8), 1203-1213.

Milner, J. M., Albon, S. D., Illius, A. W., Pemberton, J. M., & Clutton‐Brock, T. H. (1999). Repeated selection of morphometric traits in the Soay sheep on St Kilda. Journal of Animal Ecology, 68(3), 472-488.

Milner, J. M., Elston, D. A., & Albon, S. D. (1999). Estimating the contributions of population density and climatic fluctuations to interannual variation in survival of Soay sheep. Journal of Animal Ecology, 68(6), 1235-1247.

Sparks, Alexandra M., et al. “The genetic architecture of helminth-specific immune responses in a wild population of Soay sheep (Ovis aries).” PLoS Genetics 15.11 (2019): e1008461.

Visscher, P. M., Smith, D., Hall, S. J., & Williams, J. L. (2001). A viable herd of genetically uniform cattle. Nature, 409(6818), 303-303.

Williams, J. L., Hall, S. J., Del Corvo, M., Ballingall, K. T., Colli, L. I. C. I. A., Ajmone Marsan, P. A. O. L. O., & Biscarini, F. (2016). Inbreeding and purging at the genomic Level: the Chillingham cattle reveal extensive, non‐random SNP heterozygosity. Animal genetics, 47(1), 19-27.

0:00 Intro
3:47 Purebred vs. hybrid
7:45 Test crossing
12:16 Line breeding, explanation
16:06 History of the “cocker’s system”
25:40 Genetic burden; test cross within a line
35:27 Clan breeding
52:30 Mob breeding
1:09:13 Up next, outcrossing/hybridisation


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