Linkage analysis of resistance to Streptococcus iniae infection in Japanese flounder (Paralichthys olivaceus)

Streptococcal disease (streptococcosis) caused by Streptococcus iniae is a serious bacterial disease in Japanese flounder (Paralichthys olivaceus). Developing streptococcosis-resistant Japanese flounder will reduce the number of outbreaks of this disease as well as reduce the need for medicines and vaccines. Genetic linkage analysis is an effective method for identifying quantitative trait loci (QTL) associated with resistance to a disease. In this study, 159 microsatellite markers selected from genetic linkage maps of Japanese flounder and F1 progeny from crosses between disease-resistant and disease-susceptible parents were used for detection of QTL associated with resistance to this disease. Some loci associated with disease resistance were found in the JF-7, JF-10, JF-11 and JF-17 linkage groups. These QTL regions are candidates for disease resistance against streptococcal infection.