Genealogical Analysis of a Closed Herd of Black Hairless Iberian Pigs

Abstract

Livestock breeds are recognized as important components of world biodiversity. The Iberian pig is a swine breed well adapted to the Mediterranean forest ecosystem and provides cured products of high quality. The ancient population of Iberian pigs ( Sus scrofa meridionalis ) was differentiated in several local types, the black hairless pigs representing the fattest genetic type. The conservation program of the Guadyerbas strain has maintained this germplasm isolated since 1945 as a closed population in an experimental herd. The complete pedigree, with 1000 breeding animals descending from 24 founders, has been used to measure along the successive cohorts of breeding animals the effective number of founders, effective number of nonfounders, founder genome equivalents, and expected number of founders' surviving alleles. For the last cohort, the values were 10.34, 1.42, 1.25, and 4.06, respectively. The evolution of inbreeding and coancestry and its components attributable to each founder were also studied. The rate of increase in inbreeding and coancestry was 2.21% per cohort, or 0.906% per year. Finally, the effect of family structure and mating tactics on the evolution of coancestry was also analyzed. The greatest rates of coancestry per cohort were attributable to unbalanced family sizes, and the use of minimum coancestry matings effectively delayed the increase in inbreeding. Análisis Genealógico de una Manada Aislada del Cerdo Ibérico Lampiño NegroResumen: Las razas de ganado son consideradas como un componente importante de la biodiversidad mundial. El cerdo Ibérico es una raza de cerdos bien adaptada al ecosistema forestal del Mediterráneo y provee productos encurtidos de alta calidad. La población ancestral del cerdo Ibérico ( Sus scrofa meridionalis ) era diferenciada en diversos tipos locales, siendo los cerdos lampiños negros los representantes del tipo genético más gordo. El programa de conservación de la variedad Guadyerbas ha mantenido su germoplasma aislado desde 1945 como una población cerrada en una manada experimental. El pedigrí completo con 1000 animales reproductores descendientes de 24 fundadores ha sido usado para medir a lo largo de cohortes sucesivas de animales reproductores el número efectivo de fundadores, el número efectivo de no-fundadores, el genoma fundador equivalente y el número esperado de alelos fundadores sobrevivientes. Para la última cohorte, los valores fueron 10.34, 1.42, 1.25 y 4.06, respectivamente. También estudiamos la evolución de endogamia y codescendencia y sus componentes debidos a cada fundador. La tasa de incremento en endogamia y codescendencia fue del 2.21% por cohorte, o el equivalente a 0.906 % por año. Finalmente, analizamos el efecto de la estructura familiar y las tácticas de apareamiento en la evolución de la codescendencia. Las tasas más grandes de codescendencia por cohorte fueron atribuibles a tamaños familiares desbalanceados y al uso mínimo de apareamientos de codescendientes, retardando efectivamente el incremento de la endogamia.* email toro@inia.es

Genetic diversity, population structure and subdivision of local Balkan pig breeds in Austria, Croatia, Serbia and Bosnia-Herzegovina and its practical value in conservation programs

“…Numerous studies have reported observed heterozygosity values for different populations of the Landrace, Large White, Pietrain and Duroc breeds with values ranging from 0.67 to 0.50 [1,3-5,23]. The economically less important local European breeds often show reduced census and effective population sizes [28,29]. Therefore their diversity measured by genetic markers is significantly decreased and ranges from HO = 0.35 to HO = 0.58 [1,23].…”

Genome-Wide Estimates of Coancestry and Inbreeding in a Closed Herd of Ancient Iberian Pigs

“…Its meat has a high proportion of intramuscular fat with a rich content of unsaturated fatty acids which leads to highly prized products of extraordinary quality [3]. The breed also has an important role in shaping and maintaining the Dehesa, a richly diverse agrosilvopastoral system of great economic and social importance in the southwest of the Iberian Peninsula [4]. Iberian pigs are well adapted to the strong oscillations in feeding and climate conditions, typical of this geographical area, because of their capacity to accumulate fat.…”

“…It is one of the most ancient surviving Iberian strains and currently is the only representative of the black hairless genetic type. The strain has been conserved in an experimental herd as a genetically isolated population since 1944 [4]. Accurate genealogical and performance information for reproductive traits has been recorded since the foundation of the herd and this makes it a genetic resource of exceptional value.…”

The complete mitochondrial genome sequence of the indigenous I pig (Sus scrofa) in Vietnam

“…Animal mtDNA has one control region and codes for 13 protein subunits, 2 rRNAs, and 22 tRNAs [7]. The control region as known as D loop , which regulates both replication and transcription of mtDNA, has used in several previous phylogenetic studies [8,9]. …”