Screening of experimental zebrafish lineages. + and – represented wild-type allele and mutant allele, respectively; +/+ represented homozygous wild-type genotype; -/- represented homozygous mutant genotype; +/- represented heterozygous genotype, only individuals with homozygous mutant genotype (-/-) expressed the mutant phenotype, i.e. imb partial deletion. For avoiding the influence of the mutant allele to traits of individuals with heterozygous genotypes, only families with homozygous genotypes (+/+ or -/-) were chosen for this study.