QTL mapping in the chicken has been divided into three phases: the development of a linkage map, the search for linkage of quantitative traits with flanking DNA markers, and the identification and isolation of trait-genes. Our overall strategy for identifying and isolating trait-genes is to:
(i) perform low resolution QTL mapping experiments,
(ii) construct a high resolution map of the QTL, and
(iii) isolate and identify the trait-gene either by testing candidate genes or by physically cloning the region containing the QTL and identifying the genes within it.
The aim of this proposal is to develop the tools and resources to make such a strategy a practical reality.
The major objectives of CHICKMAP are: To develop a microsatellite marker map covering the entire chicken genome and optimised for whole genome linkage studies.
To integrate the physical and genetic linkage maps of the chicken. To develop methods to isolate additional markers in targeted areas of the chicken genome.
To develop a chicken-human comparative gene map.
To construct radiation hybrids for genetic and physical mapping. To work in parallel with European national research projects to map and determine the effects of QTL in specific resource populations. A number of low resolution QTL mapping experiments in chicken are underway within the collaborating laboratories, e.g. crosses designed to map QTL for production and disease-resistance traits. The aim is to analyse these in parallel with the EC-funded section of this project. As the tools and resources for QTL mapping are developed they will be made available to all collaborating partners. This will ensure a realistic validation of markers and methodologies in a number of important QTL mapping projects. Identification of candidate genes in a given region of the chicken genome will be a major problem after trait loci have been mapped. There are several direct methods for identifying coding sequences within a physically isolated region, e.g. exon trapping and cDNA screens. However, knowing the homology of a region of interest in the chicken genome with the corresponding region in human, will allow us to access the growing catalogue of genes resulting from the Human Genome Mapping Programme. We will systematically map conserved anchor loci to identify the regions of homology between the chicken and human genomes. Finally, an essential element of progressing from genetic linkage data to the physical isolation of trait-genes is the ability to "walk" along the chromosome by identifying an overlapping set of clones spanning the trait-gene locus. Recently, the development of large insert libraries, human/rodent hybrid cell lines and radiation hybrids has opened up new approaches to this problem. These methods greatly reduce the labour involved in creating physical contigs. In order to employ these new approaches in the chicken, we will develop primary resources of large insert libraries and hybrid cell lines.
Funding SchemeCSC - Cost-sharing contracts
RG20 7NN Newbury
6709 PG Wageningen
LE1 7RH Leicester