Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding

The Maremmano is an autochthonous Italian horse breed, which probably descended from the native horses of the Etruscans (VI century B.C.); the Studbook was acknowledged in 1980, and it includes 12 368 horses born from that year up to 2015. The aim of this study was to evaluate the effect of the sele...

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Main Authors: A. Giontella, C. Pieramati, M. Silvestrelli, F.M. Sarti
Format: Article
Language:English
Published: Elsevier 2019-01-01
Series:Animal
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1751731118001180
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author A. Giontella
C. Pieramati
M. Silvestrelli
F.M. Sarti
author_facet A. Giontella
C. Pieramati
M. Silvestrelli
F.M. Sarti
author_sort A. Giontella
collection DOAJ
description The Maremmano is an autochthonous Italian horse breed, which probably descended from the native horses of the Etruscans (VI century B.C.); the Studbook was acknowledged in 1980, and it includes 12 368 horses born from that year up to 2015. The aim of this study was to evaluate the effect of the selection program on the genetic variability of the Maremmano population; the analysis was performed using both the ‘Endog v 4.8’ program available at http://webs.ucm.es/info/prodanim/html/JP_Web.htm and in-house software on official pedigree data. Four Reference Populations were considered, and the most important one was the population of the 12 368 Maremmano horses officially registered in the National Studbook. The pedigree completeness of this population was very good because it was more than 90% at the third parental generation and more than 70% at the fifth generation; the pedigree traced back to a maximum of 10.50 generations with an average of 3.30 complete generations and 5.70 equivalent complete generations. The average generation interval was 10.65±4.72 years, with stallions used for longer periods than mares. The intervals ranged from 10.15±4.45 (mother–daughter) to 10.99±4.93 (father–daughter). The effective number of founders (fe) was 74 and the effective number of ancestors (fa) was 30 so that the ratio fe/fa was 2.47. The founder genome equivalents (fg) was 13.72 with a ratio fg/fe equal to 0.18. The mean of the genetic conservation index was 5.55±3.37, and it ranged from 0.81 to 21.32. The average inbreeding coefficient was 2.94%, with an increase of 0.1%/year, and the average relatedness coefficient was 5.52%. The effective population size (Ne) computed by an individual increase in inbreeding was 68.1±13.00; the Ne on equivalent generations was 42.00, and this value slightly increased to 42.20 when computed by Log regression on equivalent generations. The analysis confirmed the presence of seven traditional male lines. The percentage of Thoroughbred blood in the foals born in 2015 was 20.30% and has increased 0.21%/year since 1980; in particular, it increased more than twice (0.51%/year) until 1993 and afterwards slightly fluctuated. The pedigree analysis confirmed the completeness of genealogical information and the traditional importance that breeders gave to the male lines; although the genetic diversity of Maremmano seemed to be not endangered by the selection program, some effects on the population structure were found and a more scientific approach to genetic conservation should be incorporated in the selection plans.
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spelling doaj.art-622bc589794748d1bd6ea9c9b89ad2182022-12-21T18:44:20ZengElsevierAnimal1751-73112019-01-011311524Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreedingA. Giontella0C. Pieramati1M. Silvestrelli2F.M. Sarti3Department of Veterinary Medicine – Sportive Horse Research Center, University of Perugia, via S. Costanzo 4, 06123 Perugia, ItalyDepartment of Veterinary Medicine – Sportive Horse Research Center, University of Perugia, via S. Costanzo 4, 06123 Perugia, ItalyDepartment of Veterinary Medicine – Sportive Horse Research Center, University of Perugia, via S. Costanzo 4, 06123 Perugia, ItalyDepartment of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, ItalyThe Maremmano is an autochthonous Italian horse breed, which probably descended from the native horses of the Etruscans (VI century B.C.); the Studbook was acknowledged in 1980, and it includes 12 368 horses born from that year up to 2015. The aim of this study was to evaluate the effect of the selection program on the genetic variability of the Maremmano population; the analysis was performed using both the ‘Endog v 4.8’ program available at http://webs.ucm.es/info/prodanim/html/JP_Web.htm and in-house software on official pedigree data. Four Reference Populations were considered, and the most important one was the population of the 12 368 Maremmano horses officially registered in the National Studbook. The pedigree completeness of this population was very good because it was more than 90% at the third parental generation and more than 70% at the fifth generation; the pedigree traced back to a maximum of 10.50 generations with an average of 3.30 complete generations and 5.70 equivalent complete generations. The average generation interval was 10.65±4.72 years, with stallions used for longer periods than mares. The intervals ranged from 10.15±4.45 (mother–daughter) to 10.99±4.93 (father–daughter). The effective number of founders (fe) was 74 and the effective number of ancestors (fa) was 30 so that the ratio fe/fa was 2.47. The founder genome equivalents (fg) was 13.72 with a ratio fg/fe equal to 0.18. The mean of the genetic conservation index was 5.55±3.37, and it ranged from 0.81 to 21.32. The average inbreeding coefficient was 2.94%, with an increase of 0.1%/year, and the average relatedness coefficient was 5.52%. The effective population size (Ne) computed by an individual increase in inbreeding was 68.1±13.00; the Ne on equivalent generations was 42.00, and this value slightly increased to 42.20 when computed by Log regression on equivalent generations. The analysis confirmed the presence of seven traditional male lines. The percentage of Thoroughbred blood in the foals born in 2015 was 20.30% and has increased 0.21%/year since 1980; in particular, it increased more than twice (0.51%/year) until 1993 and afterwards slightly fluctuated. The pedigree analysis confirmed the completeness of genealogical information and the traditional importance that breeders gave to the male lines; although the genetic diversity of Maremmano seemed to be not endangered by the selection program, some effects on the population structure were found and a more scientific approach to genetic conservation should be incorporated in the selection plans.http://www.sciencedirect.com/science/article/pii/S1751731118001180maremmano horsefounders analysisgenetic diversityeffective population sizeselection program
spellingShingle A. Giontella
C. Pieramati
M. Silvestrelli
F.M. Sarti
Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding
Animal
maremmano horse
founders analysis
genetic diversity
effective population size
selection program
title Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding
title_full Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding
title_fullStr Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding
title_full_unstemmed Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding
title_short Analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis: structure, genetic variability and inbreeding
title_sort analysis of founders and performance test effects on an autochthonous horse population through pedigree analysis structure genetic variability and inbreeding
topic maremmano horse
founders analysis
genetic diversity
effective population size
selection program
url http://www.sciencedirect.com/science/article/pii/S1751731118001180
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AT cpieramati analysisoffoundersandperformancetesteffectsonanautochthonoushorsepopulationthroughpedigreeanalysisstructuregeneticvariabilityandinbreeding
AT msilvestrelli analysisoffoundersandperformancetesteffectsonanautochthonoushorsepopulationthroughpedigreeanalysisstructuregeneticvariabilityandinbreeding
AT fmsarti analysisoffoundersandperformancetesteffectsonanautochthonoushorsepopulationthroughpedigreeanalysisstructuregeneticvariabilityandinbreeding