Population analysis of the Poodle (Standard) breed Genetic analysis of the Kennel Club pedigree records of the UK Poodle (Standard) population has been carried out with the aim of estimating the rate of loss of genetic diversity within the breed and providing information to guide a future sustainable breeding strategy. The population statistics summarised provide a picture of trends in census size, the number of animals used for breeding, the rate of inbreeding and the estimated effective population size. The rate of inbreeding and estimated effective population size indicate the rate at which genetic diversity is being lost within the breed. The analysis also calculates the average relationship (kinship) among all individuals of the breed born per year and is used to determine the level of inbreeding that might be expected if matings were made among randomly selected dogs from the population (the expected rate of inbreeding). Summary of results The analysis utilises the complete computerised pedigree records for the current UK Kennel Club registered Poodle (Standard) population, and statistics were calculated for the period 1980-2014. 1
Figure 1: a plot of number of registrations by year of birth, indicative of any changing trend in popularity of the breed, followed by the yearly trend in number of animals registered (and 95% Breed: Poodle (Standard) Figure 1: Number of registrations by year of birth Trend of registrations over year of birth (1980-2014) = 0.34 per year (with a 95% confidence interval of -9.01 to 9.68). 2
Table 1: census statistics by year, including sire use statistics. Table 1: by year (1980-2014), the number of registered puppies born, by the number of unique dams and sires; maximum, median, mode, mean and standard deviation of number of puppies per sire; and the percentage of all puppies born to the most prolific 50%, 25%, 10% and 5% of sires. year #born #dams #sires puppies per sire %puppies sired by most prolific sires max median mode mean sd 50% sires 25% sires 10% sires 5% sires 1980 212 142 94 10 2 1 2.26 1.84 75.94 53.77 29.25 18.87 1981 623 213 131 28 3 1 4.76 4.65 81.86 59.39 32.91 21.19 1982 838 239 138 39 4.5 2 6.07 5.57 80.07 55.97 31.74 19.21 1983 902 251 147 40 4 2 6.14 6.07 80.38 58.54 34.04 19.62 1984 948 258 137 66 4 2 6.92 8.85 84.6 63.92 40.51 26.27 1985 1127 295 149 175 5 1 7.56 14.89 83.67 62.29 39.93 27.6 1986 1059 286 162 62 4 2 6.54 6.77 81.87 58.55 31.16 19.17 1987 1085 285 152 53 4 2 7.14 8.25 83.69 61.57 36.59 25.53 1988 1090 261 147 45 5 4 7.41 7.09 82.02 57.43 32.29 18.99 1989 1655 279 145 107 7 6 11.41 13.96 82.3 60.91 39.88 25.14 1990 1361 220 123 63 7 6 11.07 11.39 78.47 58.56 35.78 22.19 1991 1397 228 134 71 9 9 10.43 9.04 75.88 52.61 28.7 19.54 1992 1157 182 109 55 8 7 10.61 9.21 75.8 52.72 30.25 17.89 1993 1463 223 124 95 8 8 11.8 12.37 78.54 57.21 33.56 21.8 1994 1394 221 120 58 9 6 11.62 9.56 76.76 54.3 29.05 17.07 1995 1526 239 116 100 9 8 13.16 13.42 79.1 57.21 33.22 21.95 1996 1376 216 112 64 8 6 12.29 11.66 79.51 56.76 32.19 21.95 1997 1395 218 121 72 8 7 11.53 12.26 79.71 57.99 36.7 23.44 1998 1308 194 119 61 8 7 10.99 9.99 77.37 55.89 32.49 19.88 1999 1140 178 117 61 7 7 9.74 9.18 78.77 56.49 33.07 20.26 2000 948 156 100 35 8 1 9.48 8.05 80.91 55.17 28.9 17.09 2001 1004 157 99 45 8 8 10.14 7.94 76.79 51.69 27.79 17.13 2002 1050 165 109 47 8 6 9.63 7.63 75.52 50.95 28.67 16.38 2003 1134 175 100 56 9 1 11.34 9.6 78.92 53.17 29.01 18.17 2004 990 152 87 80 7 1 11.38 13.05 83.54 61.31 36.57 23.03 2005 1061 165 91 47 10 1 11.66 9.8 81.15 54.38 28.93 18.38 2006 985 155 99 88 7 6 9.95 11.47 78.78 56.95 36.45 24.97 2007 1049 166 109 80 7 1 9.62 10.29 81.03 57.39 34.03 20.59 2008 1031 156 106 75 8 9 9.73 9.69 76.14 53.06 33.17 21.05 2009 924 140 78 58 8 7 11.85 11.16 79.98 57.47 33.77 20.56 2010 1078 182 115 45 7 1 9.37 7.93 78.76 53.8 30.06 18.18 2011 947 162 109 42 7 1 8.69 7.37 79.3 53.22 29.57 16.47 2012 848 146 105 48 7 1 8.08 7.16 78.3 52.36 31.49 18.63 2013 856 145 98 54 7 7 8.73 8.66 78.39 55.61 34 22.66 2014 949 138 92 35 9 5 10.32 6.97 75.03 48.16 24.45 15.28 3
Generation interval: the mean average age (in years) of parents at the birth of offspring which themselves go on to reproduce. Mean generation interval (years) = 3.88 Figure 2: a plot of the annual mean observed inbreeding coefficient (showing loss of genetic diversity), and mean expected inbreeding coefficient (from random mating ) over the period 1980-2014. Expected inbreeding is staggered by the generation interval and, where >2000 animals are born in a single year, the 95% confidence interval is indicated. Figure 2: Annual mean observed and expected inbreeding coefficients 4
Estimated effective population size: the rate of inbreeding (slope or steepness of the observed inbreeding in Figure 2) is used to estimate the effective population size of the breed. The effective population size is the number of breeding animals in an idealised, hypothetical population that would be expected to show the same rate of loss of genetic diversity (rate of inbreeding) as the breed in question. It may be thought of as the size of the gene pool of the breed. Below an effective population size of 100 (inbreeding rate of 0.50% per generation) the rate of loss of genetic diversity in a breed/population increases dramatically (Food & Agriculture Organisation of the United Nations, Monitoring animal genetic resources and criteria for prioritization of breeds, 1992). An effective population size of below 50 (inbreeding rate of 1.0% per generation) indicates the future of the breed many be considered to be at risk (Food & Agriculture Organisation of the United Nations, Breeding strategies for sustainable management of animal genetic resources, 2010). Where the rate of inbreeding is negative (implying increasing genetic diversity in the breed), effective population size is denoted n/a. Estimated effective population size = n/a NB - this estimate is made using the rate of inbreeding over the whole period 1980-2014 5
Table 2: a breakdown of census statistics, sire and dam usage and indicators of the rate of loss of genetic diversity over 5 year periods (1980-4, 1985-9, 1990-4, 1995-9, 2000-4, 2005-9, 2010-14). Rate of inbreeding and estimated effective population size for each 5-year block can be compared with the trend in observed inbreeding in Figure 2. Table 2: by 5-year blocks, the mean number of registrations; for sires the total number used, maximum, mean, median, mode, standard deviation and skewness (indicative of the size of the tail on the distribution) of number of progeny per sire; for dams the total number used, maximum, mean, median, mode, standard deviation and skewness of number of progeny per dam; rate of inbreeding per generation (as a decimal, multiply by 100 to obtain as a percentage); mean generation interval; and estimated effective population size. years 1980-1984 1985-1989 1990-1994 1995-1999 2000-2004 2005-2009 2010-2014 mean #registrations 704.6 1203.2 1354.4 1349 1025.2 1010 935.6 Total #sires 390 437 340 337 290 293 321 Max #progeny 120 345 235 232 140 224 154 Mean #progeny 9.0103 13.753 19.915 20.012 17.672 17.232 14.564 Median #progeny 4 6 10 9 11 9 10 Mode #progeny 1 2 8 7 1 1 1 SD #progeny 14.189 24.809 27.277 30.469 20.081 23.641 17.101 Skew #progeny 3.9138 7.3292 3.8088 3.7705 2.4087 3.7993 3.2343 Total #dams 837 1008 766 753 571 574 567 Max #progeny 28 40 43 43 42 35 33 Mean #progeny 4.1983 5.9623 8.8277 8.9562 8.9755 8.7962 8.2451 Median #progeny 3 5 8 7 8 8 7 Mode #progeny 1 3 8 7 8 7 1 SD #progeny 3.5711 4.8769 6.1012 6.1631 6.5322 6.0877 6.0239 Skew #progeny 2.1185 2.1736 1.7425 1.6155 1.5283 1.1932 1.159 Rate of inbreeding 0.024476-0.01351 0.012916-0.00918-0.00265-0.00809-0.00894 Generation interval 3.6706 3.5487 4.1114 4.112 4.2515 3.8726 3.5687 Effective pop size 20.428 n/a 38.71 n/a n/a n/a n/a 6
Figure 3: a histogram ( tally distribution) of number of progeny per sire and dam over each of the seven 5-year blocks above. A longer tail on the distribution of progeny per sire is indicative of popular sires (few sires with a very large number of offspring, known to be a major contributor to a high rate of inbreeding). Figure 3: Distribution of progeny per sire (blue) and per dam (red) over 5-year blocks (1980-4 top, 2010-14 bottom). Vertical axis is a logarithmic scale. 7
Comments As with most breeds, the rate of inbreeding was at its highest in this breed in the 1980s and early 1990s. However, since the mid-1990s the rate of inbreeding has slowed and even declined slightly, implying maintenance and even some replenishment of genetic diversity (possibly through the use of imported animals). It appears that the extensive use of popular dogs as sires has eased a little (the tail of the blue distribution shortening in figure 3). It should be noted that, while animals imported from overseas may appear completely unrelated, this is not always the case. Often the pedigree available to the Kennel Club is limited in the number of generations, hampering the ability to detect true, albeit distant, relationships. 8