AU Zekarias, B
   Ter Huurne, AAHM
   Landman, WJM
   Rebel, JMJ
   Pol, JMA
   Gruys, E<br>
TI Immunological basis of differences in disease resistance in the chicken<br>

SO VETERINARY RESEARCH<br>

AB Genetic resistance to diseases is a multigenic trait governed mainly by the immune system and its interactions with many physiologic and environmental factors. In the adaptive immunity, T cell and B cell responses, the specific recognition of antigens and interactions between antigen presenting cells, T cells and B cells are crucial. It occurs through a network of mediator proteins such as the molecules of the major histocompatibility complex (MHC), T cell receptors, immunoglobulins and secreted proteins such as the cytokines and antibodies. The diversity of these proteins that mainly is due to an intrinsic polymorphism of the genes causes phenotypic variation in disease resistance. The well-known linkage of MHC polymorphism and Marek's disease resistance difference represents a classic model revealing immunological factors in resistance differences and diversity of mediator molecules. The molecular bases in any resistance variation to infectious pathogens are vaguely understood. This paper presents a review of the major immune mediators involved in resistance and susceptibility to infectious diseases and their functional mechanisms in the chicken. The genetic interaction of disease resistance with production traits and the environment is mentioned.<br>
PY 2002 
PD MAR?APR 
VL 33 
IS 2 
BP 109 
EP 125 
<p>
AU Weigend, S
   Romanov, MN<br>
TI Current strategies for the assessment and evaluation of genetic diversity in chicken resources<br>

SO WORLDS POULTRY SCIENCE JOURNAL<br>

AB Chicken genetic resources comprise a wide range of breeds and populations including red jungle fowl (the assumed progenitor of all domestic breeds), native and fancy breeds, middle level food producers, industrial stocks and specialised lines. Based on the suggestion that the more distant a breed or population is the more likely it is to carry unique genetic features, the assessment of genetic distances by means of molecular marker information may provide useful information for initial evaluation of chicken genetic resources. During the last two decades several molecular marker classes have become available. Variable numbers of tandem repeat loci, in particular microsatellites, have been successfully used in chicken diversity studies. Genetic diversity measures using the highly polymorphic variable number of tandem repeat loci yield reliable and accurate information for the study of genetic relationships between chicken populations. First results of the European project on chicken biodiversity (AVIANDIV) obtained from microsatellite typing in DNA pools of 51 diverse chicken breeds showed that jungle fowl populations, traditional unselected breeds and broiler lines appear to be widely heterogeneous populations that may include a large portion of the genetic diversity of the tested breeds. In contrast, highly selected strains (layers and experimental lines) are characterised by a lower polymorphism. They behave as outliers from the set of breeds sampled. Single nucleotide polymorphism is a new and very promising molecular marker system which offers opportunities to assess the genetic diversity in farm animal species differently by investigating the mode and extent of changes in certain positions in the genome.<br>

PY 2001 
PD SEP 
VL 57 
IS 3 
BP 275 
EP 288 
<p>
AU Pisenti, JM
   TI Avian genetic resources at risk: An assessment and proposal for conservation of genetic stocks in the USA and Canada
SO AVIAN AND POULTRY BIOLOGY REVIEWS
PY 2001
VL 12
IS 1?2
BP 1
EP +
PG 97
UT ISI:000168212000002
ER

PT J
AU Delany, ME at al.<br>

TI Conservation of poultry genetic research resources: Consideration of the past, present and future<br>

SO POULTRY AND AVIAN BIOLOGY REVIEWS<br>

AB Well?defined genetic populations of poultry, principally the chicken, turkey and Japanese quail, have held important roles in both basic and applied research. The recent elimination of a number of unique avian genetic research stocks and the imperiled?status of entire research collections as well as specific lines within relatively?stable collections, has alarmed biologists who value and utilize such stocks. Unfortunately, despite recommendations by numerous scientists (e.g. Crawford, 1990a; Bitgood, 1993), committees and workshops (e.g. McGuire and Qualset, 1984) and councils (e.g. Council for Agricultural Science and Technology, 1984), no formal plan exists for the conservation of poultry genetic research resources. This review focuses on the development and use of poultry genetic resources for research; in particular we focus on the available genetic models and highlight their contribution to agriculture, basic biology and biomedicine. The current status of poultry genetic resources in North America is reviewed. A proposal for a North American Avian Genetic Resources System (NAAGRS) is outlined. The proposal, drafted by members of the Avian Genetic Resources Task Force (AGRTF), formulates general guidelines and options for the conservation of poultry genetic research stocks to guarantee the future and long-term availability of these valuable, irreplaceable resources.<br>

PY 1998 
VL 9 
IS 1 
BP 25 
EP 42