A First Sorghum Composite Linkage Map Was Constructed with Heterologous Probes Already

GENOME MAPPING AND QTL ANALYSIS IN BARRAMUNDI (LATES CALCARIFER)

Chun Ming Wang1, Gen Hua Yue1, Loong Chueng Lo1, Zeyuan Zhu1, Felicia Feng1, Grace Lin1, R. Chou2, H.S. Lim2, and L. Orban3 1 Molecular Population Genetics Group, Temasek Life Sciences Lab, 117604 Singapore 2 Agri-Food & Veterinary Authority of Singapore, Singapore 3 Reproductive Geneomics Group, Temasek Life Sciences Lab, 117604 Singapore Email: chunming @tll.org.sg A first generation genetic linkage map of Barramundi (Lates calcarifer), an important farmed marine food fish species, was established with a mapping panel containing three parents (two males and one female) and 93 progenies. Two hundred and forty microsatellite markers were mapped into 24 linkage groups (LGs). Among these markers, 10 were located in ESTs and known genes. The total lengths of the female and male maps were 873.8 cM and 414.5 cM with an average marker spacing of 6.20 cM and 4.70 cM respectively. About 350 new markers including ~100 microsatellites in ESTs and candidate genes will be integrated into the first generation map. Based on the linkage map, we conducted a genome scan for QTL affecting body weight, total and standard length and condition factors in an F1 family containing 380 full- sib individuals from a breeding stock by using 97 microsatellites evenly covering 24 chromosomes. Five significant and 27 suggestive QTL were detected on ten LGs. This study presents the first example of QTL detection for growth-related traits in an F1 family of a marine foodfish species. Verification of the detected QTL was conducted in two F1 families with different genetic backgrounds. Results showed that some QTL were family-specific, and demonstrated that the use of multiple populations held great promise for better understanding the architecture of genetic variation. Construction of a second generation linkage map and a BAC genomic DNA library is underway. QTL and gene mapping for traits related to meat quality and disease resistance will be conducted by using the physical and genetic maps in the near future.

References:

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