QTL detection of production traits for the Kuruma prawn Penaeus japonicus (Bate) using AFLP markers

The objective of this study was to use Amplified Fragment Length Polymorphism (AFLP) markers to determine the genetic location and effects of genomic regions controlling weight (WT), total length (TL) and carapace length (CL) in one full-sib Penaeus japonicus family. One hundred and two extreme progeny from an intermediate F2 cross of high (HH) and low (LL) growth parents were used to identify these regions. Two analytical methods were applied in this study. They were interval mapping (IM) and composite interval mapping (CIM). There was no significant marker-trait association in the female map. One region controlling part of the variation for CL and TL was identified in linkage group 1 of the male map by IM, and the same region and one other suggestive QTL marker in linkage group 25 of the male map were detected by CIM. Both regions were located on the end of linkage groups. In order to derive additional markers, the Bulk Segregant Analysis (BSA) technique was applied to these regions to generate further AFLP markers. From 45 markers scored using 11 AFLP primer combinations, one AFLP marker was mapped to the QTL region in linkage group 1 and one in the middle of group 25. The new results supported the findings from the early analyses prior to using BSA. The magnitude of phenotypic variation explained by the joint action of the QTL markers indicated that genetic factors of large effect were involved in the control of the studied characters. This study is the first to identify QTLs for growth traits in a penaeid species.