COEFFICIENT OF INBREEDING
COI – an important factor of dog breeding
Coefficient of inbreeding (COI) with the Chart Polski
Pia Parikka
Master of Science in Agriculture and Forestry
Graduate Agronomist
Polskis kennel
piaros2001 @ yahoo.com
Breeding relatives with eachother is called inbreeding. It can have serious affects called inbreeding depression. The most common results of inbreeding are lower life expectance, lower vitality and lower fertility. The main reason for inbreeding depression is that the number of harmful recessive genecombinations is increased. Also the number of favorable dominance effects and the number of favorable gene combinations is decreased.
Inbreeding unifies the DNA which also causes uniformity in appearance. This is probably the biggest reason why inbreeding is used in dog breeding despite its negative affects. Within Chart Polski the number of founder dogs is low which causes basically all Chart Polski being more or less inbred. This problem can be minimized by enlargening the genetic pool of Chart Polski with new founder dogs that are unrelated to the pedigreed population. Calculating inbreeding coefficients for each litter and trying to minimize it also helps.
Inbreeding coefficient resembles the degree of inbreeding on individual dog. It can be derived from the degree of relationship between the parents by dividing their relationship coefficient in half. It is difficult to say when inbreeding coefficient is too high, but quite often the limit is set somewhere between 3–6% (0,03–0,06) with all known generations.
It is recommended to use a computer program to calculate inbreeding coefficients in complex cases such as in Chart Polski. Calculating inbreeding coefficients without computer programs can be quite difficult because usually the parents are already inbred.
Here is a link to download Pedigree Viewer that can be used in creating pedigrees and calculating inbreeding coefficients:
http://www-personal.une.edu.au/~bkinghor/pedigree.htm
Literature:
Bourdon, R. M. 1997: Understanding animal breeding
Falconer, D. and Mackay, T. 1995: Introduction to quantitative genetics
Cameron, N. D. 1997: Selection indices and prediction of genetic merit in animal breeding
Updated: September 17th 2007
Development of the COI in Chart Polski
Lea Hämäläinen
Breeding consultant of the Chart Polski / Finnish Sighthound Club
Emericius kennel
chartpolski @ kolumbus.fi
1977–1981
5,4 %
1982–1986
13 %
1987–1991
15 %
1992–1996
8,3 %
1997–2001
8,1 %
2002–2006
11 %
2007–
11 %
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The figures in the above table are counted as the average of all documented litters born in Europe within five year intervals. Then the COI is calculated with max. 9 generations for each paring.
When examining the situation it is worth keeping in mind, what these values mean in practice. Paring littermates gives 25%, while paring child to one of the parents gives 12,5%, respectively. Paring cousins gives 6,25%. This is valid as long as there is no additional inbreeding in the paring. At present, the growth of the COI is too fast and the level of the COI generally too high.
Obs! These figures are counted on the grounds of well known pedigrees. They are valid only provided the pedigrees are correctly documented!Dans ce tableau les pourcentages de consanguinité ils sont calculés comme les moyennes des périodes de cinq années, sur la base des tous les portées nées en Europe. Dans le calcul on a pris en compte au maximum 9 générations.
Quand on envisage le sens de ces chiffres, il faut se rappeler que l'accouplement de sœur et frère ce donne le coefficient de consanguinité 25 %, d' un descendant et un des parents 12,5 % et des cousins 6,25 %. C'est ainsi, s'il n' y a pas une autre consanguinité d'auparavant dans le pedigree de cette combinaison. L'augmentation de la consanguinité c'est actuellement trop rapide et d'un point de vue général le niveau de consanguinité c'est trop haut.
Attention! Ces informations sont calculés sur la base des pedigrees connus. Ils sont exacts seulement si les pedigrees sont vrais!Updated: September 12th 2008