tailieunhanh - Báo cáo sinh học: "Exploring the assumptions underlying genetic variation in host nematode resistance"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Exploring the assumptions underlying genetic variation in host nematode resistance | Genet. Sel. Evol. 40 2008 241-264 INRA EDP Sciences 2008 DOI gse 2008001 Available online at Original article Exploring the assumptions underlying genetic variation in host nematode resistance Open Access publication Andrea Beate DOESCHL-WILSON1 Dimitrios VAGENAS2 Ilias KYRIAZAKIS2 3 Stephen Christopher BISHOP4 1 Sustainable Livestock Systems Scottish Agricultural College West Mains Road Edinburgh EH9 3JG UK 2 Animal Health and Nutrition Department Scottish Agricultural College West Mains Road Edinburgh EH9 3JG UK 3 Faculty of Veterinary Medicine University of Thessaly Trikalon 224 43100 Karditsa Greece 4 Roslin Institute and Royal Dick School of Veterinary Studies Roslin BioCentre Midlothian EH25 9PS UK Received 18 July 2007 accepted 21 December 2007 Abstract - The wide range of genetic parameter estimates for production traits and nematode resistance in sheep obtained from field studies gives rise to much speculation. Using a mathematical model describing host - parasite interactions in a genetically heterogeneous lamb population we investigated the consequence of i genetic relationships between underlying growth and immunological traits on estimated genetic parameters for performance and nematode resistance and ii alterations in resource allocation on these parameter estimates. Altering genetic correlations between underlying growth and immunological traits had large impacts on estimated genetic parameters for production and resistance traits. Extreme parameter values observed from field studies could only be reproduced by assuming genetic relationships between the underlying input traits. Altering preferences in the resource allocation had less pronounced effects on the genetic parameters for the same traits. Effects were stronger when allocation shifted towards growth in which case worm burden and faecal egg counts increased and genetic correlations between these resistance traits and body weight became stronger. Our study has .