AFLP linkage map of sea urchin constructed using an interspecific cross between Strongylocentrotus nudus (♀) and S. intermedius (♂)

The interspecific cross between Strongylocentrotus nudus (♀) and S. intermedius (♂) holds significant heterosis in growth and disease resistance. For the purposes of genetic studies and breeding, AFLP linkage maps were constructed for both S. nudus (♀) and S. intermedius (♂) using a hybrid population with a two-way pseudotestcross strategy. Forty-two selective amplification primer combinations produced 897 polymorphic AFLP bands that were polymorphic in either of the parents and segregated in the progeny. Twenty four linkage groups of S. nudus contained 194 AFLP markers, covering a total length of 2988.3 cM, with an average marker spacing of 17.1 cM. In S. intermedius, 199 AFLP markers were mapped in 23 linkage groups, covering a total length of 2614.8 cM, with an average of 15.4 cM between markers. The expected map length and coverage were estimated to be 3827.5 cM and 78.1% for S. nudus and 3307.8 cM and 79.1% for S. intermedius respectively.