a secondgeneration genetic linkage map for bighead carp aristichthys nobilis based on microsatellite markers bighead carp aristichthys nobilis is an important aquaculture fish worldwide genetic linkage maps for the species were previously reported but map resolution remained to be improved in this study a secondgeneration genetic linkage map was constructed for bighead carp through a pseudotestcross strategy using interspecific hybrids between bighead carp and silver carp of the 754 microsatellites genotyped in two interspecific mapping families with 77 progenies for each family 659 markers were assigned to 24 linkage groups which were equal to the chromosome numbers of the haploid genome the consensus map spanned 19173 cm covering 928 of the estimated bighead carp genome with an average marker interval of 29 cm the length of linkage groups ranged from 522 to 1335 cm with an average of 799 cm the number of markers per linkage group varied from 11 to 55 with an average of 275 per linkage group normality tests on interval distances of the map showed a nonnormal marker distribution however significant correlation was found between the length of linkage group and the number of markers below the 001 significance level twotailed the length of the female map was 112 times that of the male map and the average recombination ratio of female to male was 1101 visual inspection showed that distorted markers gathered in some linkage groups and in certain regions of the male and female maps this welldefined genetic linkage map will provide a basic framework for further genome mapping of quantitative traits comparative mapping and markerassisted breeding in bighead carp