Breeding new strains of tilapia: development of an artificial center of origin and linkage map based on AFLP and microsatellite loci

Based on ideas from plant breeding and the opportunities offered by molecul ar biology, a program was initiated in 1995 to derive genetically superior tilapia from a synthetic stock (artificial center of origin, AGO) produced by inter-crossing dye groups of fish: Oreochromis niloticus [wild-type (On) and red (ROn) strains], O. aureus (Oa), O, mossambicus (Om), and Sarothero don galilaeus (Sg). Three-way cross families (3WC) and four-way cross famil ies (4WC) have been produced, so that all four species are represented in t he AGO. A genomic map has been created for each of the parents in an Om X ( Oa X ROn) family using microsatellite and AFLP (amplified fragment length p olymorphism) DNA markers. nle female (Om) parent had a total of 78 segregat ing markers (17 microsntellites, 61 AFLPs). Of these, 61 (13 microsatellite s, 49 AFLPs) were linked in 14 linkage groups covering a total of 514 centi morgans (cM). The first generation (F-1) hybrid male parent had a total of 229 segregating markers (62 microsatellites, 167 AFLPS), of which 214 (60 m icrosatellites, 154 AFLPs) were linked in 24 linkage groups covering a tota l of 1632 cM. The construction of these maps is a key Step in a molecular m arker-assisted breeding program to detect quantitative trait loci (QTL) for cold and salinity tolerance and carcass quality in tilapia. (C) 2000 Elsev ier Science B.V. All rights reserved.