Hox gene expression profiles during embryonic development of common sole: Supplementary material

Common sole (<i>Solea solea</i>) aquaculture production is based mostly on wild-caught breeders. Recently, the successful reproduction of first-generation fish that were reared in captivity was accomplished. A consistent good quality and quantity of produced eggs throughout the year, and of next-generation broodstock, is important for reducing the overall cost of production. <i>Hox</i> genes play a pivotal role in normal embryonic development and alterations of their temporal expression level may be important for egg viability. Expression profile analysis of six <i>hox </i>genes (<i>hoxa1a, hoxa2a, hoxa2b, hoxb1a </i>and <i>hoxb1b) </i>involved in early embryonic development and of <i>hoxa13a</i>, which is<i> </i>involved in late stages, was carried out. <a>Results revealed a premature and/or maternal expression of <i>hoxa13a </i>in sole embryos, and the detection of <i>hoxa2a </i>and <i>hoxa2b </i>genes as members of paralog group 2. Principal Component Analysis of <i>hox </i>gene expression in 54 ± 6 hours post fertilization embryos coming from wild-caught broodstock and a first-generation one reared in the hatchery, unveiled that these broodstocks are clearly distinct. In addition, their pairwise comparison revealed significant differences in the expression levels of <i>hoxb1a </i>and <i>hoxb1b</i> genes. </a>Hox gene regulation during embryonic development could give valuable insight into rearing sole broodstocks with different origin in concert, and also into gaining a steady mass production of eggs, either in quality or quantity, all year round.