Genetic variability and population structure of Raeini Cashmere goat breed assessed from pedigree analysis

Pedigree information which collected from 1979 to 2012 were used to study the genetic variability and population structure of Raeini Cashmere goat, taking kids born from 2009 to 2012 into account as reference population. Averages of inbreeding coefficients in whole and inbred populations were computed to be 0.04% and 4.41%, respectively. Considering the reference population, average inbreeding coefficient and average relatedness of 0.14 % and 0.11% were obtained, respectively. Mean of generation interval, computed from four gametic pathways (sire-son, sire-daughter, dam-son and dam-daughter), was 3.72 years, with a longer interval from dam-progeny pathways relative to sire-progeny ones. In the reference population, average equivalent complete generation, as a measure of pedigree completeness, was 1.25. Effective population size was estimated from the individual rate in coancestry and from the individual increase in inbreeding as 332 and 229, respectively. The effective numbers of founders (fe) and the effective numbers of ancestors (fa) were estimated 240 and 137, respectively. Approximately, 50% of total genetic variation was explained by the first 57 influential ancestors, with a maximum individual contribution of 3.94%. The ratio of fe to fa, as measure of bottleneck, was 1.75. The obtained results revealed the evidences for occurrence of bottlenecks in the population, mainly because of unbalanced contribution of breeding animals to gene pool of the studied population of Raeini Cashmere goat.