Microsatellite-Directed Selection of Breeders for the Next Backcross Generation by using a Minimal Number of Loci

摘要

Toestablishaminimalnumberofmarkersfordirectselectionofcandidatemiceusedforthenextmatingtoproducecongenicmice,recombinationfrequenciesof53microsatellitelocionchromosomes(chr.)1and19wereexaminedusing41N2mice:thedonorstrainwasBALB/c,andrecipientstrainwasC57BL/6J(B6J)orC57BL/6N(B6N).Thesemarkerswerespacedat0.1to24.2centimorgans(cM).Amongthe41mice,B6/B6homozygosityrangedfrom18to24animals(mean,20;2standarddeviations,1.36)foragivenlocus.Therewasnodifferenceinrecombinationfrequencybetweenchr.1and19.TherecombinationfrequencyofB6JwashigherthanthatofB6N(P0.05).Variousdensitiesofmarkers,10(5markers/chr.),8(4markers/chr.),and6(3markers/chr.)spacedat12.0to29.3,9.0to45.0,and24.5to53.0cM,respectively,wereselectedfromthe53markers,andhomozygositywascomparedineachmouse.Inmicewithdecreasedhomozygositywhentestedusing53markers,homozygositydiffereddependingonthedensityofthemarkers.Theresultssuggestedthat3markers/chr.aresufficientforselectionofthehighestpercentagesofhomozygositybutarenotsuitabletodefinemicewithlowerpercentagesofhomozygosity.