Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/1995
Publication Date: N/A
Interpretive Summary: Genetic maps are powerful tools for dissecting the underlying genes that influence traits of economic importance. Therefore, a prerequisite for genetic analysis of trait is the existence of a genetic map for that species. Furthermore, for a genetic map to be useful, it must be fairly saturated and contain genetic markers that can be easily applied. We have developed a genetic map of the chicken that includes 273 genetic markers. To increase the usefulness of our map, we have concentrated on placing genetic markers of high utility known as microsatellites. Based on our current estimates, there is at least one marker of high utility for every region of the chicken genome. When we applied our genetic markers of high utility to other diverse chicken populations, we found that approximately 66 percent of the markers could be used, on average, in any one population. Thus, our present genetic map with markers of high utility can be useful to many chicken populations (e.g., commercial breeding flocks). Ultimately, this genetic map will provide the tool necessary to make breeding quicker, more accurate, and more economical.
Technical Abstract: Microsatellites are tandem duplications with a simple motif of one to six bases as the repeat unit. Microsatellites provide an excellent opportunity for developing genetic markers of high utility because the number of repeats is highly polymorphic, and the assay to score microsatellite polymorphisms is quick and reliable since the procedure is based on the polymerase chain reaction (PCR). We have identified 404 microsatellite containing clones of which 219 were suitable as microsatellite markers. Primers for 151 of these microsatellites were developed and used to detect polymorphisms in DNA samples extracted from the parents of two reference populations and three resource populations. 60%, 39%, 46%, 49% and 61% of the microsatellites exhibited length polymorphisms in the East Lansing reference population, the Compton reference population, resource population #1 (resistance genes to Marek's disease), resource population #2 (genes involved in abdominal fat), and resource population #3 (genes involved in production traits), respectively. The 91 microsatellites that were polymorphic in the East Lansing reference population were genotyped and 86 genetic markers were eventually mapped. In addition, 11 new random amplified polymorphic DNA (RAPD) markers and 24 new markers based on the chicken CR1 element were mapped. The addition of these markers increases the total number of markers on the East Lansing genetic map to 273 of which 243 markers are resolved into 32 linkage groups. The map coverage within linkage groups is 1402 cM with an average spacing of 6.7 cM between loci. The utility of the genetic map is greatly enhanced by adding 86 microsatellite markers. Based on our current map, about 2550 cM of the chicken genome is within 20 cM of at least one microsatellite marker.