The agribusiness knowledge provider
This article also
available in
PDF
Video
PPT

Tech Forum Alert


Genetic diversity and networks of exchange: a combined approach to assess intra-breed diversity

 
Jean-François Dumasy, Christel Daniaux, Isabelle Donnay and Philippe V Baret
   
       

Background


Cryopreservation of three endangered Belgian sheep breeds required to characterize their intra-breed genetic diversity. It is assumed that the genetic structure of a livestock breed depends mostly on gene flow due to exchanges between herds. To quantify this relation, molecular data and analyses of the exchanges were combined for three endangered Belgian breeds.


Methods


For each breed, between 91 and 225 sheep were genotyped with 19 microsatellites. Genetic differentiations between breeds and among herds within a breed were evaluated and the genetic structure of the breeds was described using Bayesian clustering (Structure). Exchanges of animals between 20, 46 and 95 herds according to breed were identified via semi-directed interviews and were analyzed using the concepts of the network theory to calculate average degrees and shortest path lengths between herds. Correlation between the Reynolds' genetic distances and the shortest path lengths between each pair of herds was assessed by a Mantel test approach.


Results


Genetic differentiation between breeds was high (0.16). Overall Fst values among herds were high in each breed (0.17, 0.11 and 0.10). Use of the Bayesian approach made it possible to identify genetic groups of herds within a breed. Significant correlations between the shortest path lengths and the Reynolds' genetic distances were found in each breed (0.87, 0.33 and 0.41), which demonstrate the influence of exchanges between herds on the genetic diversity. Correlation differences between breeds could be explained by differences in the average degree of the animal exchange networks, which is a measure of the number of exchanges per herd. The two breeds with the highest average degree showed the lowest correlation. Information from the exchange networks was used to assign individuals to the genetic groups when molecular information was incomplete or missing to identify donors for a cryobank.


Conclusions


A fine-scale picture of the population genetic structure at the herd level was obtained for the three breeds. Network analysis made it possible to highlight the influence of exchanges on genetic structure and to complete or replace molecular information in establishing a conservation program.

 


For more of the article, please click here.


Article made possible through the contribution of Jean-François Dumasy, Christel Daniaux, Isabelle Donnay, Philippe V Baret and BioMed Central.

Share this article on FacebookShare this article on TwitterPrint this articleForward this article
Previous
Subscribe To eFeedLink 
Copyright ©2017 eFeedLink. All rights reserved.
Find us on FacebookFind us on Twitter