A microsatellite linkage map of the European sea bass Dicentrarchus labrax L

Abstract

A genetic linkage map of the European sea bass (Dicentrarchus labrax) was constructed from 174 microsatellite markers, including 145 new markers reported in this study. The mapping panel was derived from farmed sea bass from the North Adriatic Sea and consisted of a single family including both parents and 50 full-sib progeny (biparental diploids). A total of 162 microsatellites were mapped in 25 linkage groups. Eleven loci represent type I (coding) markers; 2 loci are located within the peptide Y (linkage group 1) and cytochrome P450 aromatase (linkage group 6) genes. The sex-averaged map spans 814.5 cM of the sea bass genome. The female map covers 905.9 cM, whereas the male map covers only 567.4 cM. The constructed map represents the first linkage map of European sea bass, one of the most important aquaculture species in Europe.

Figure 1.—

Sex-averaged linkage map in Kosambi centimorgans of the European sea bass consisting of 25 linkage groups.

Figure 2.—

Male linkage map in Kosambi centimorgans of the European sea bass consisting of 25 linkage groups.

Figure 3.—

Female linkage map in Kosambi centimorgans of the European sea bass consisting of 25 linkage groups.

Figure 4.—

Haploid karyotype of the European sea bass obtained from a cultured haploid embryo cell. The haploid number is 24. The chromosomes from 1 to 23 have the centromere in the terminal region (telocentric-acrocentric); chromosome 24 has a heteropycnotic short arm, which may vary in length. This heteropycnotic region corresponds to the nucleolar organizer region. Due to the interindividual variability of the length of the short arm of chromosome 24, this chromosome may be classified from submetacentric to acrocentric (Sola et al. 1993).