Genetic diversity and population structure of the Spanish Murciano-Granadina goat breed according to pedigree data

- The Murciano-Granadina goat breed retained a considerable rate of genetic diversity and there is no evidence of bottleneck.
- The adequate use of external animals as parents promoting gene flow and increasing the genetic diversity.
- There was no signal of substructure, but a small number of ancestors contributed with 50% of the intra-breed genetic diversity.

The genetic diversity and population structure of the Spanish Murciano-Granadina goat breed were assessed by pedigree data analysis, which is essential for addressing conservation and improvement breed programs. We analysed 24,444 pedigree data records for the Murciano-Granadina goat breed (797 males and 23,647 females), distributed across 49 herds, for the period from 1992 to 2006. The average generation interval based on the age of the parents at the birth of offspring was 2.77 ± 1.33 years. Although the study did not identify a genetic bottleneck (fa/fe = 1.00), 50% of the genetic variability was provided by only 366 ancestors, which may contribute to future genetic bottlenecks if the current mating policy is maintained. The number of equivalent generations increased from 1995 to 1997, followed by a decrease until 1999, when returned to growth. This oscillation could have been affected by difficulties in recording the genealogical data for young animals. The average values of F and AR for the entire analysed pedigree were 0.180% and 0.03%, respectively. Only 0.74% of the animals were inbred, but a high average (24.68%) was observed. The average GCI was very low (1.64), indicating a small, unbalanced contribution of the founders in the population. The average inbreeding was lower than the AR value during the studied period for the entire population, which indicates low genetic variation between populations but large intra-herd genetic diversity.