Construction And Comparisons Of Sea Cucumber(Apostichopus Japonicus) Full-sib Families And Preliminary Construction Of Genetic Linkage Map

Family selection is an important method for selective breeding in aquatic animals.Large-scale family breeding technology of sea cucumber has not been establisheduntil now. In this study, Full-sib sea cucumber families were constructed usingparental sea cucumber from different populations of the germplasm resources. Thenthe growth properties including body length, body breadth, number of papilla line andtotal number of papilla were measured and the anti-bacterial activity were detectedamong the full-sib families. Genetic linkage map of sea cucumber was constructedusing AFLP and SSR markers. The results were listed as follows:1. The oviposition rate reached46.7%by parent-independent ovipositionalstimulants Eleven full-sib sea cucumber families were constructed byparent-independent ovipositional stimulants with artificial insemination using threeparental sea cucumber populations-Japanese cultured sea cucumber (RC), Qingdaowild sea cucumber (QW) and sea cucumber with multiple papilla (DC).Relationship between parental growth characters with fertilization rate, hatching rate,metamorphosis rate and deformity rate were analyzed. It was revealed that there was apositive correlation between maternal parental weight with fertilization rate, hatchingrate and metamorphosis rate. There was a negative correlation between maternalparental weights with deformity rate. Genetic diversity analysis showed that thereexisted a relatively abundant genetic diversity in the total parents. F7has the highestand F3has the lowest polymorphic loci rate of the two parents in total full-sibfamilies. Judged by the genetic distance between the two parents of the same family,parents of F5has the minimum genetic distance and parents of F9and F11has themaximum genetic distance.2. The body weight and body length of each families seeds were measured from3to12months and revealed that the variation of growth characteristics in the familiesincreased along with age growth. The growth properties including body length, body breadth, number of papilla line and total number of papilla were measured andanalyzed using12month old seeds in the11full-sib families. The results showed thattwo families (F10and F11) which were constructed using RC() and DC() had themost significiant growth dominance. Anti-bacterial activity was also detected judgedby the survival rate of the family through artificial infection using Vibrio Splendidus.It was showed that two families (F6and F9) which were constructed using QW()and RC() had the most dominant anti-bacterial activity. There is no relationshipbetween properties dominance and genetic distance of the parents in family pedigreeselective breeding.3. Genetic maps of sea cucumber were constructed using F7full-sib family withmicrosatellite DNA and amplified fragment length polymorphisms (AFLP) markersand two-way pseudo-testcross strategy. The map of female sea cucumber consisted of119markers (11SSR and108AFLP) which were assembled into22linkage groups.The length of these linkage groups ranged from10.2to116.1cM, and the number ofmarkers varied from2to10per group. The average mark interval was24.6cM and amaximum marker interval was67.1cM, and the gonome of the frame was497.26cM.The total length of the map was1108.68cM including the doublets and the triplets.Meanwhile the expected genome length was2304.62cM. The map coverage was48.11%of the estimated genome size.The map of male sea cucumber consisted of85markers (7SSR and78AFLP)which were assembled into9linkage groups. The length of the linkage group rangedfrom3.2to149.2cM, and the number of markers varied from2to18per group. Theaverage mark interval was21.1cM and a maximum marker interval was47.8cM, andthe gonome of the frame was302.41cM. The total length of the map was484.32cMincluding the doublets and the triplets. Meanwhile the expected genome length was891.36cM. The map coverage was54.33%of the estimated genome size.